A HANDBOOK TO THE MINERALOGY CORNWALL AND DEVON T R U R : PRINTED BY HEARD AND SONS, BOSCAWEN STREET. HANDBOOK MINERALOGY OF CORNWALL AND DEVON, WITH INSTRUCTIONS FOE THEIR DISCRIMINATION, AND COPIOUS TABLES OF LOCALITIES, J. H. COLLINS, F.G.S., VN LECTURER AND ASSISTANT SECRETARY TO THE MINERS' ASSOCIATION OF CORNWALL AND DEVON; SECRETARY TO THE KOYAL CORNWALL POLYTECHNIC SOCIETY; ASSOCIATE OF THE KOYAL GEOLOGICAL SOCIETY OF CORNWALL, AND OF THE ROYAL INSTITUTION OF CORNWALL, &C., &C. TRURO: HEARD AND SONS. LONDON: LONGMANS, GREEN, READER, AND DYER. 1871. SCIENCES ROBERT WERE FOX, F.R.S., THE DISCOVERER OP THB ELECTRICITY OF MINERAL LODES IN CORNWALL, AND OF MANY CORNISH MINERALS, (WHOSE OBSERVATIONS EXTEND OVER MORE THAN HALF A CENTURY), THIS HANDBOOK TO THE MINERALOGY OF CORNWALL AND DEVON IS DEDICATED, BY HIS SINCERE ADMIRER AND MOST OBEDIENT SERVANT, THE AUTHOR. 229974 PREFACE. This Handbook is the product of the few hours of brief leisure of a busy life. It is intended primarily as a Work of Reference for the Student, the Mine Agent, and the Working Miner : that such a work has been much needed will be conceded by all. The Author cannot hope to have altogether escaped errors ; and no doubt omissions and faults are not wanting. The faults are his own ; but he trusts there are also some excellencies, since he has received valuable assistance from those who have been well acquainted with the subject for many years. His thanks are especially due to Robert Were Fox, Esq., F.R.S.; Robert Hunt, Esq., F.R.S ; Professor Warington W. Smyth, F.R.S.; Wm. Jory Henwood, Esq., F.R.S.; Professor A. H. Church; Richard Pearce, Esq., F.G.S.; and many other gentle- men, who have favoured him with information as to localities, &c. FALMOUTH, September, 1871. LIST OF WORKS CONSULTED. EEPOKTS OF THE KOYAL GEOLOGICAL SOCIETY or CORNWALL, Yols. I. to VII. REPORTS OF THE ROYAL INSTITUTION OF CORNWALL, 1838-1870. REPORTS OF THE ROYAL CORNWALL POLYTECHNIC SOCIETY, 1833-1870. TRANSACTIONS OF THE DEVONSHIRE ASSOCIATION. A MANUAL OF MINERALOGY, TRURO, 1828? AN ELEMENTARY INTRODUCTION TO THE KNOWLEDGE OF MINERALOGY, by WM. PHILLIPS, 1823. A MANUAL OF MINERALOGY, by BROOKE and MILLER, 1852. MANUAL OF THE MINERALOGY OF GREAT BRITAIN AND IRELAND, by R. P. GREG and W. G. LETTSOM, 1854. A MANUAL OF MINERALOGY, by J. NICOL, 1849. A GLOSSARY OF MINERALOGY, by H. W. BRISTOW, 1861. THE MINERALOGIST'S DIRECTORY, by T. M. HALL, A SYSTEM OF MINERALOGY, by J. D. DANA, 1868. JOURNAL OF THE CHEMICAL SOCIETY, CHEMICAL NEWS. GEOLOGICAL MAGAZINE. PHILOSOPHICAL MAGAZINE, &c., &c. LIST OF ABBREVIATIONS OCCASIONALLY EMPLOYED. B., etc., for Blowpipe and other "dry " reactions. Comp. ,, Chemical Composition. Loc. ,, Localities. Obs. ,, Observations. OF Oxidizing Flame. RF Eeducing Flame. Co. Nitrate of Cobalt (in Solution.) Sol. Soluble. Insol. ,, Insoluble. HC1. Hydrochloric Acid. H 2 SO 4 Sulphuric Acid. HNO 3 Nitric Acid. KHO Caustic Potash (in Solution.) Fus. Fusibility. C. Charcoal. Micro ,, Microcosmic Salt. Soda Carbonate of Soda. H. Hardness. G. ,, Specific Gravity. CONTENTS. PART I. 'PAGE. DEDICATION y. PREFACE vii. LIST OF "WORKS CONSULTED viii. LIST OF ABBREVIATIONS ix. TABLE OF CONTENTS x. ERRATA xi. CHAPTER I. INTRODUCTORY 1 CHAPTER II. DETERMINATIVE TABLE I. REACTIONS IN MATRASS 3 II. REACTIONS IN OPEN TUBE III. REACTIONS ON CHARCOAL WITHOUT FLUXES 5 IV. REACTIONS WITH COBALT 6 Y. REACTIONS ON CHARCOAL WITH FLUXES 6 VI. REACTIONS WITH BORAX BEAD 6 VII. REACTIONS WITH MICROCOSMIC SALT 8 VIII. FLAME COLORATIONS 10 IX. REACTIONS WITH SOLVENTS 10 X. GROUP I. PULVERULENT 12 II. FOLIACEOUS 13 III. CAPILLARY 14 IV. SAPID 15 V MALLEABLE 16 VI. PLASTIC 16 VII. COLOUR AND STREAK BLUE 16 VIII. COLOUR AND STREAK GREEN ... 17 IX. COLOUR AND STREAK RED, YELLOW, OR BROWN 18 X. COLOUR VARIOUS, STREAK DARK, H. BELOW 5 20 XI. COLOUR VARIOUS, STREAK DARK, H. 5-6 22 XII. COLOUR VARIOUS, STREAK LIGHT, H. BELOW 5 23 XIII. COLOUR VARIOUS, STREAK LIGHT, H. 5-6 25 XIV. COLOUR VARIOUS, H. 6 AND UPWARDS 26 XV. COLOUR VARIOUS, COMBUSTIBLE OR VOLATILE CHAPTER III. DESCRIPTIVE NOMENCLATURE OF CORNISH MINERALS TABLE OF THE ELEMENTS CHAPTER IV. SYSTEMATIC SYSTEM I. CHEMICAL II. ECONOMICAL III. MIXED IV. CRYSTALLOGRAPHIC CHAPTER V. DISTRIBUTIVE LIST OF MINES, &c., CORNWALL LIST OF MINES, &c., DEVON ^ CHAPTER VI. PARAGENETIC .... PART II. ALPHABETICAL LIST OF MINERALS IN CORNWALL AND DEVON PLATES, WITH DESCRIPTIONS ADDENDA LIST OF SUBSCRIBERS ... ERRATA. P. 12, Pt. II., col. 2, Loc., line 10. For Carharrack read Carharrack, St. Just. P. 34, Pt. II., col. 1, Loc., line 18. For Tin read Cassiterit*. P. 71, Pt. II., col. 1, line 23. For Kerargyrite read Kerat*. A HAND-BOOK TO THE MINERALOGY OF CORNWALL AND DEVON, PART I. CHAPTER I. INTRODUCTORY. A perfect definition is proverbially a very difficult, if not impossible, thing to produce. The definition of a mineral is no exception, but one of the best runs as follows: "A mineral is any natural, homogeneous body, inorganically produced." This definition is defective, inasmuch as it excludes coal, as well as bog iron ore and some other substances, usually described as minerals j but if the third character be not too rigidly applied it is tolerably correct. The student having obtained a new specimen is naturally desirous to know what its properties are. He will then desire to determine whether any similar mineral has been described before. Next he will wish to know how to arrange it with his other specimens, as well as where it has occurred before ; and, finally, he will endeavour to ascertain the conditions of its occurrence. A division of the Science of Mineralogy into the following five sections (as defined on p. 70, Part II.) would therefore seem to be tolerably natural. SECTION 1. Determinative. 2. Descriptive. 3. Systematic. ,, 4. Distributive. ,, 5. Paragenetic. In this "Handbook" only a very brief outline of these various branches can be given. Such an outline may, however, prove sufficient for many miners and amateurs, and it may also serve as a convenient introduction to larger and more complete works for those who desire to pursue the subject. For special and detailed instruction in the use of the blowpipe the author would recommend "An Introduction to the Use of the Mouth-Blowpipe," by T. Scheerer and H. F. Blandford (Williams and Norgate, 1864), or the large work of Professors Plattner and Muspratt, published by Messrs. Churchill. A list of the apparatus used for the experiments described in this Handbook is appended. Those marked thus, (*), are essential ; for the others an ingenious student will usually be able to devise substitutes. * 1. Blowpipe (Dr. Black's form is convenient and cheap). * 2. An oil-lamp with flat wick, or a thick candle. 3. A spirit lamp. * 4. Several pieces of charcoal. * 5. Small glass tabes, open, and sealed at one end. * 6. Borax. * 7. Carbonate of soda. * 8. Microcosmic salt. * 9. Solution of nitrate of cobalt. 10. A small mortar of porcelain, or, much better, of agate or jasper; 2 CHAPTER XL DETEEMINATIYE. 11. Brass forceps, with, platinum points. 12. Small steel-faced hammer and anvil. 13. Three-sided file, finely cut, for trying the hardness of minerals, cutting glass tubes, &c. * 14. A magnet. * 15. A pocket magnifying glass. 16. Several watch-glasses. 17. Several test tubes. 18. Potassic bisulphate. 19. Boric acid. 20. Fluor spar. 21. Gypsum. 22. Oxide of copper. 23. Metallic lead, tin, copper, and iron, in thin plate or foil, and fine wire. 24. Bone ash- 25. Test papers litmus or turmeric, and Brazil wood. 26. Distilled water. 27. Sulphuric acid. * 28. Nitric acid. * 29. Hydrochloric acid. * 30. Ammonia in solution. 31. Caustic potash in solution. * 32. Thin platinum wire. 33. Platinum foil. 34. Scale of hardness. 35. Scale of fusibility. 36. Penknife. 37. Contact goniometer. CHAPTER II. DETEKMINATIVE. To determine the nature of an unknown mineral specimen it will be advisable to adopt a system, and to adhere closely to it, for some time at least. Supposing such a specimen to be placed in the hands of the student he should examine it carefully, noting down the results of his examination according to the instruc- tions contained in this chapter. A large number of minerals occur, at least occasionally, in more or less regular geometrical forms termed "crystals." These have been grouped into six systems of crystallization," for convenience of study (see "Crystallography," p. 38, Part II.) It is no part of the purpose of this work to explain the sub- science of crystallography;* but a great deal may be learnt by a careful comparison of the specimen under examination with the figures on Plates I. to X., with their explanations. If amorphous, or occurring in imitative forms, it should also be noted. A portion of the specimen should now be powdered for examination according to the tables I. to X. While doing so a good opportunity is afforded for noticing its cleavage and fracture, and determining its " Hardness " and other PHYSICAL CHAKACTERS. Its peculiar OPTICAL CHARACTERS, as colour, lustre, &c., should be at the same time carefully noted, after which the student may proceed to test its CHEMICAL CHARACTERS with the aid of the tables given. These observations may very well be made in the order indicated below. Most of the terms used are specially explained in another part of the work. * Those who wish to follow up this delightful part of the subject will do well to procure Nicol's "Manual of Mineralogy," Naumann's "Elemente der Mineralogie," or some similar work. CHAPTER II. DETEEMINATIVE. 1. FORM !?' } See Crystallography, p. 38. 2. PHYSICAL CHARACTERS other than form Cleavage, see p. 34. Franglbility or Tenacity, } See p * 48 ' Hardness, see p. 54. Specific Gravity, see p. 94. Magnetism, see p. 66. Electricity, see p. 42. 3. OPTICAL CHARACTERS Colour, see p. 35. Streak, see p. 98. Lustre, see p. 65. Diaphaneity, see p. 41. Phosphorence, see p. 77. Fluorescence, see p. 47. Refractive Power. Polarization. 4. CHEMICAL CHARACTERS Fusibility, see p. 49. Solubility, see p. 94. Taste, see p. 100. Odour, see p. 72. Adhesion to tongue. Touch, see p. 102. 5. BLOWPIPE REACTIONS, see p. 18. The specimen to be examined by the aid of the following tables should be selected as free as possible from foreign matter and reduced to a coarse powder, in a mortar or otherwise. It should then be subjected to the experiment? detailed on p. 18, Part II. , and the results compared with the following tables, which are applicable to substances of artificial production, as well as to minerals. TABLE I. REACTIONS IN MATRASS. BXP 1. Heat a small portion in a matrass (see p. 18). A. The substance turns black, and gives off pungent odours and much moisture. Organic matter is indicated. B. The substance changes colour, but no moisture or sublimate is evolved a. From white, yellow, grey, or brown, to black. The carbonates of iron, manganese, and some other substances behave thus. Carbonate of iron (Chalybite) becomes strongly magnetic ; peroxide of iron (Hematite) is black while hot, but dark reddish-brown when cold. b. From orange-red to brown while hot, again orange-red on cooling. Potassic bichromate and some other chromates and bichromates behave thus. c. From yellow or pink to reddish-brown while hot, yellow when cold, fusible with a strong heat ; oxide of lead is probable. d. From yellow to deep orange-red while hot, lemon-yellow when cold. Chromate of potash or some other chromate is probable. e. White or pale yellow to a stronger yellow while hot, losing colour again on cooling. Oxide of zinc or oxide of tin is indicated. f. White to deep orange or reddish-brown while hot, yellow when cold, fusible at a white heat. Oxide of bismuth is probable. Many other substances change colour on heating, but most of them give off moisture or a sublimate at the same time, and are therefore included in other parts of this table. O. The assay decrepitates, some anhydrous substance is indicated. When the powder is very fine this reaction is not often observed. Among minerals CHAPTER II. DETERMINATIVE. WOLFRAM and BLENDE often decrepitate strongly; of artificial substances CHLORATE OF POTASH and NITRATE OF LEAD are good examples. D. Water is given off, and deposited on the sides of the tube. a. The assay melts at first, gives off much water, and finally re-solidifies. Salts containing water of crystallization are indicated. Among minerals Melanterite and Kalinite (alum) are good examples. b. Gives off moisture without melting or swelling up. Many hydrates or hydrous carbonates behave thus. Those of the heavy metals often become much darker at the same time. Among minerals Malachite, Chessylite, and Kaolin are good examples. The first two turn nearly black ; the third remains white. c. The quantity of water may be inconsiderable, and given off at a low temperature. This is often water of absorption, taken up by the substance from the air. In all cases the moisture should be tested with " test paper." If acid, some volatile acid, such as SULPHURIC or NITRIC, is indicated. If alkaline, AMMONIA is present. E. The assay fuses more or less readily, but gives off little or no water. In such cases, while strongly heated, a fragment of charcoal should be dropped in. A deflagration will indicate a NITRATE, PER-NITRATE, CHLORATE, or PER-CHLORATE. This reaction is rarely to be expected when exainining a mineral substance. F. Gases and vapours other than steam are given off. (These will rarely be observed in this experiment with mineral substances.) a. The gas re-lights a glowing splint of wood. Oxygen is indicated from CHLORATES, NITRATES, PEROXIDES, &c. The former are often fusible; peroxides will be usually infusible. b. An odour of burning sulphur is noticed. Sulphurous anhydride, from SULPHATES and other bodies containing sulphur. c. The gas is brownish or reddish. NITRATES and NITRITES are indicated. d. The gas is colourless and without odour, but if conducted into "lime- water" renders it turbid. Carbonic anhydride fromCARBo e.g., CALCITE, ARAGONJTE, DOLOMITE, &c., among mineral substances. e. The gas is without colour and has but little odour, but burns with a blue flame. Carbonic oxide from OXALATES and similar salts. f. The gas burns with a rose-coloured flame. Cyanogen from CYANIDES, FERRO-CYANIDES, &c. g. The gas has an odour like that of rotten eggs, and blackens "lead- paper." Sulphuretted hydrogen from SULPHIDES, &c. h. Strong pungent odour, and turns reddened litmus paper blue* A mmonia f rom ammoniacal salts and nitrogenous organic compounds. G. A " sublimate " is deposited. fa. Sublimes after fusion, substance very heavy. MEBCURIC CHLORIDE is probable. b. Sublimes without fusion ; substance heavy ; yellow while hot. MERCUROUS CHLORIDE is probable. c. Sublimes without fusion ; not heavy. AMMONIC CHLORIDE is -J probable. d. Sublimes without fusion ; substance rather heavy ; sublimate crys- talline. ARSENIC ANHYDRIDE, Arsenolite, if altogether volatile, or some METALLIC ARSENIDE, if mostly non-volatile. e. Sublimes after fusion ; substance very light. Benzoic 'or some other organic acid is probable. ( a. Fuses at first to a yellow liquid. OXIDE of ANTIMONY is probable, b. Red or reddish-yellow while hot, yellow when cold. SULPHIDE of ARSENIC is indicated. (Orpiment and Realgar among mineral sub- J stances, as well as many sulpharsenides.) c. Original substance red, and sublimate red when rubbed. Iodide of Mercury is probable. d. Sublimate easily melts to reddish-brown drops. SULPHUR or some SULPHIDE is indicated. CHAPTER II. DETEEMINATIVE. - g /-a. Turns red when rubbed. SULPHIDE of MERCURY is indicated, from o -g ) CINNABAR and other mercuric minerals. ^ rt s ) k R ema i ns black when rubbed. SULPHIDE of ANTIMONY, from ANTI- M 02 V MONITE and other minerals containing antimony. ^ sq j a. Runs into drops when rubbed. MERCURY is shewn to be present. b. Remains as an opaque crust. ARSENIC is probable, from many 2 JK 3 I minerals containing ARSENIC. PQ^- 02 V In cases where a sublimate or a gas is given off, some additional information, or more precise results, may be obtained by making experiment 2. Whenever, by the foregoing table, ammonia, arsenic, mercury, or antimony are thought to be indicated, more distinct reactions may be obtained by mixing the assay with a little " Black Flux," and heating in a fresh matrass. TABLE II. REACTIONS IN OPEN TUBE. EXP. 2. Heat a fresh portion of the substance under examination in a tube, open at both ends, and held in an inclined position. (This experiment may be omitted in all cases where no change was effected by the first experiment.) A. A white sublimate is formed. This may be fa. OXIDE of ANTIMONY, from ANTIMONITE, &c. | b. OXIDE of ARSENIC, from ARSENIDES. This sublimate will be in brilliant crystals. c. OXIDE of BISMUTH, from BISMITE, BISMUTHINITE, &c. This would be yellow or reddish-brown while hot. d. CHLORIDE of LEAD. This is readily fusible. e. OXIDE of LEAD. Yellow while hot ; fusible at a red heat. f. SULPHATE of LEAD, from Galena, &c. g. CHLORIDES of MERCURY, from Salts of Mercury, h. SELENITE of LEAD, from the very rare ISelenide. i. OXIDE of MOLYBDENA, from minerals containing Molybdena. This sublimate is in pale yellow shining crystals. IJ. OXIDE of TELLURIUM, from the very rare metallic TELLURIDES. n f (3 These are precisely as in the first experiment, with the addition of 5 3 I molybdic anhydride, which sublimes in pale yellow crystals. ^ P3 Z* t* I B. Gases or vapours may be evolved a. SULPHUREOUS, from metallic Sulphides. b. Resembling GARLIC (alliaceous), from compounds containing Arsenic. c. Resembling DECAYING HORSE RADISH. From Selenides a red sub- limate of Selenium is often deposited. TABLE III. REACTIONS ON CHARCOAL WITHOUT FLUXES. EXP. 3. Make a small cavity on the surface of a piece of charcoal, place a portion of the substance to be examined in it, direct the tip of the flame of a candle or oil-lamp upon it by means of the blowpipe, using first the " oxidizing flame," afterwards the "reducing flame." A. The substance melts, and is mostly absorbed by the charcoal without depositing an "incrustation." Many alkaline salts behave thus, but few minerals. B. An incrustation is deposited on the charcoal, especially when the reducing flame is used. Sometimes a small metallic bead will be produced from the assay at the same time. Those most likely to be met with are the following : 6 CHAPTER II. DETEKMINATIVE. a. White. Garlic odour. AESENIC is indicated. Ex. NATIVE AKSENIC, SMALTITE, &c. b. White. Little or no odour. Brittle metallic globules in RF. ANTIMONY is indicated. c. White. Yellow while hot ; malleable bead. Ex. TIN. d. White. Yellow while hot ; no bead. Ex. ZlNC. e. Yellow. Soft malleable bead. Ex. LEAD. f. Yellow or orange. Soft brittle bead. Ex. BISMUTH. g. Reddish-brown. Easily volatilized ; no bead. Ex. CADMIUM. h. Dark red. Very bright white malleable bead. Ex. SILVER. These reactions are often somewhat obscured by the presence of several together. C. A white, or nearly white, residue is left on the charcoal. This may, perhaps, indicate Barium, Strontium, Lime, Magnesia, Alumina, Zinc, Silica. Proceed to Exp. IV., Table IV. D. A dark coloured residue is left. This indicates the presence of some heavy metal. Proceed to Exps. as in Tables V., VI., VII. E. The tip of the flame is seen to be tinged red, yellow, blue, green, &c. Examine by Exp., Table VIII. TABLE IV. REACTIONS WITH COBALT SOLUTION. EXP. 4. "When a white residue is left from Exp. 3, either Baryta, Strontia, Lime, Magnesia, Oxide of Zinc, Alumina, or Silica is probably present. In such cases moisten with a drop of a solution of Nitrate of Cobalt (Co), and heat strongly again. A. If it appears intensely luminous, Strontium, Lime, Magnesia, or Oxide of Zinc are probably present. B. If as it cools, it turns a. Blue. ALUMINA is present ; SILICA, if only pale blue. b. Green. ZINC is present. c. Pink or red. MAGNESIA is present. TABLE V. REACTIONS ON CHARCOAL WITH FLUXES. EXP. 5. When a dark coloured residue is left from Exp. 3, mix a little dry carbonate of soda with the assay and heat in the "Reducing Flame" (RF). See p. 18, Part II. a. Yellow malleable bead = GOLD. b. Red malleable bead = COPPER. c. White malleable bead, dull as it cools, white incrustation = TIN. d. White malleable bead, very bright, dark red incrustation = SILVER. e. Grey malleable bead, yellow incrustation = LEAD. f. Grey brittle bead, yellow incrustation = BISMUTH. g. White brittle bead, white incrustation = ANTIMONY. h. White incrustation, easily volatilized, with garlic odour, no bead = ARSENIC. i. White incrustation, no odour, no bead, green when treated with Co = ZINC. j. Reddish-brown incrustation, no bead = CADMIUM. TABLE VI. REACTIONS WITH BORAX BEAD. EXP. 6. Make a "borax bead" and examine a portion of the assay (after roasting if any sublimate was yielded by EXPS. 1 and 2), as in EXP. 6, p. 18, Part II. (Substances printed in italics are very rare.) A. Oxidising Flame. A. COLOURLESS BEADS. ( Silica, Alumina, Binoxide of Tin, Baryta, \ when highly saturated ; U OT I Strontia, Lime, Magnesia, Oxide of Silver, Vopaque (white) by flam- AND -I ^ ucina - Tellurous A nhydride. ) ing. COLD ' Titanic Anhydride, Tungstic Anhydride, \ I Molybdic Anhydride, Oxides of Zinc, Cad- )when feebly saturated. Lead, Bismuth and Antimony. CHAPTER II. DETEEMINATIYE. b. YELLOW BEADS. ' Titanic Anhydride, Tungstio Anhydride, 1^ MgUy attted ; Oxides of Zinced Cadmium. fluTyb/flating? ' Oxides of Lead, Bismuth, and Anti- ) when highly saturated ; TT J mony. j on cooling colourless. j Sesquioxides of Cerium, Iron, and ) when feebly saturated; Uranium. ) on cooling colourless. Sesquioxide of Chromium ; when fully saturated ; when cold, I yellowish-green. L Vanadic Anhydride-, when cold, pale green. c. RED TO BROWN BEADS. f Sesquioxide of Cerium ; on cooling yellow, enamel-like by flaming. I Sesquioxide of Iron ; on cooling yellow. Sesquioxide of Uranium ; on cooling yellow, enamel-yellow by HOT. { flaming. Sesquioxide of Chromium ; on coolieg yellowish-green. I Sesquioxide of Iron, containing Manganese ; on cooling yellowish- ^red. Oxide of Nickel (reddish -brown to brown); violet while hot. COLD. ^ Sesquioxide of Manganese (violet-red); violet while hot. Oxide of Nickel, containing Cobalt ; violet while hot. d. VIOLET BEADS (AMETHYST-COLOURED). >wn to brov violet -red. )wnish. ( Oxide of Nickel ; on cooling reddish-brown to brown. HOT. s Sesquioxide of Manganese ; on cooling violet-red. V. Oxide of Nickel, containing Cobalt ; on cooling brownis e. BLUE BEADS. HOT. -{ Oxide of Cobalt ; retains its colour on cooling. COLD i Oxide of Copper (when highly saturated greenish-blue); green ' \ while hot. f. GREEN BEADS. ( Oxide of Copper; when cold, blue or greenish -blue. ""I on cooling the colour Sesquioxide of Iron, containing Cobalt or changes, according to HOT. \ Copper. I the proportion in which Oxide of Copper, containing Iron or (the various oxides are I Nickel. present, to light-green L j blue, or yellow. ( Sesquioxide of Chromium, yellowish-green ; yellow to red while COLD. < hot. (, Vanadic A nhydride, greenish ; yellow while hot. B. Reducing Flame, a. COLOURLESS BEADS. f Silica, Alumina, Binoxide of Tin. Sesquioxide of Manganese ; sometimes, on cooling, pale rose COLD coloured ' Oxides of Silver, Zinc, Cadmium, Lead, ") with strong blowing; I Bismuth, Antimony, Nickel, Tellurous An- With feeble blowing {hydride. ) grey. TT ( Oxide of Copper ; when highly saturated ; on cooling opaque and I red. CHAPTER II. DETERMINATIVE. b. YELLOW TO BROWN BEADS. f Titanic Anhydride (yellow to brown); when highly saturated 1 enamel-blue by flaming. HOT. -I Tungstic Anhydride (yellow to dark yellow); when cold brownish. I Molybdic Anhydride (brown to opaque). t. Vanadic Anhydride (brownish); green when cold. c. BLUE BEADS. HOT. -{ Oxide of Cobalt ; retains its colour on cooling. d. GREEN BEADS. HOT C Sesquioxide of Iron (yellowish-green); especially when cold. Sesquioxide of Uranium (yellowish-green); when highly saturated black by naming. Sesquioxide of Chromium (light to dark emerald-green). HOT. -{ Vanadic Anhydride ; brownish while hot. e. GREY AND CLOUDY BEADS. ^ colourless. COLD, f <**f o^^er,Z^ C Cadmium, Lead,) | Bismuth, Antimony, Nickel. /co f. RED AND OPAQUE BEADS. COLD. -{ Oxide of Copper, when highly saturated ; colourless while hot. TABLE VII. REACTIONS WITH MICROCOSMIC SALT. Substances printed in italics are very rare. A. Oxidising Flame, a. COLOURLESS BEADS. ( Silica ; soluble only in minute quantity. ! Alumina, Binoxide of Tin ; soluble with difficulty. 1 when highly saturated Baryta, Strontia, Lime, Magnesia. >become opaque by flam- J ing. Tungsten, Antimony ; Oxides of Zinc, \ if not too highly satu- Cadmium, Lead, Bismuth, Titanium. f rated. b. YELLOW BEADS. Anhydrides of Tungsten^ Antimony, of Zin< TT J Oxide of Silver, yellowish ; when cold opalescent. ] Sesquioxide of Iron. ) when feebly saturated ; ,, Cerium. j on cooling colourless. Uranium ; when cold yellowish-green. Vanadic Anhydride, deep yellow ; when cold of a lighter shade. COLD, -( Oxide of Nickel; while hot reddish. c. RED BEADS. ) when highly saturated ; Ti-., J ,, Cerium. J when cold yellow. LOT. <^ ^.^ ^^.^ _.,... when cold yellow. reddish ; when cold emerald-green. CHAPTER II. DETERMINATIVE. 9 d. VIOLET BEADS. HOT. -{ Oxide of Manganese, brownish -violet ; on cooling pale reddish- violet, e. BLUE BEADS. HOT. -{ Oxide of Cobalt ; when cold of the same colour. COLD. -{ Oxide of Copper ; green while hot. f. GREEN BEADS. f ^ on cooling the colour Sesquioxide of Iron, containing Cobalt or changes, according to Copper. I the proportion in which Oxide of Copper, containing Iron or (the various oxides are HOT. -{ Nickel. | present, to light green, J blue, or yellow. Oxide of Copper ; when cold blue or greenish-blue. 1 Molybdic Anhydride, yellowish-green ; when cold of a lighter t shade. COLD I Sesquioxide of Uranium, yellowish-green ; while hot yellow. ' t Sesquioxide of Chromium, emerald-green ; while hot reddish. B. Reducing- Flame. a. COLOUELESS BEADS. C Silica ; but slightly soluble. Alumina, Binoxide of Tin ; soluble with difficulty. 'J when highly saturated J Baryta, Strontia, Lime, Magnesia. Vbecome opaque by flam- j ing. Oxides of Manganese, Cerium. COLD. | Oxides of Silver, Zinc, Cadmium, Lead,^ I Bismuth. Antimonious anhydride. > with continued blowing. Oxide of Nickel, if the exp. be made on I Charcoal. J b. YELLOW TO RED BEADS. C Sesquioxide of Iron ; on cooling greenish, then reddish. Titanic Anhydride, yellow ; on cooling violet. HOT. s Vanadic Anhydride, brownish; when cold emerald-green. Titanic Anhydride, containing Iron. ) yellow ; when cold L Tungstic Anhydride, J blood-red. c. VIOLET BEADS. COLD. { Titanic Anhydride ; yellow while hot. d. BLUE BEADS. p f Oxide of Cobalt ; of the same colour when hot. yOLD. ^ Tungstic Anhydride ; while hot brownish. e. GREEN BEADS. Sesquioxide of Uranium ; while hot less bright. Molybdic Anhydride ; while hot of a dirty green colour. Vanadic Anhydride ; while hot brownish. _ Sesquioxide of Chromium ; while hot reddish f. GREY AND CLOUDY BEADS. {~ -, . T , 1 takes place quickest on Oxides of Silver, Zinc Cadmium, Lead, I Ch ^ continued Bismuth, Antimony, Nickel. /blowing colourless. g. KED AND OPAQUE BEADS. COLD. { Oxide of Copper, when highly saturated, or with Tin on Charcoal. B 10 CHAPIER II. DETERMINATIVE. TABLE VIII. FLAME COLOURATIONS. BX.P. 8. A fragment of the substance under examination is held by platinum-pointed forceps, and the tip of the oxidising flame is directed on it a piece of platinum wire with a little of the powder sticking to it will usually uffice. (Note Substances containing easily reduceable metals, as tin or lead, or substances which yield sublimates by Exp. 1, should not be thus treated, as the platinum forceps would be spoiled. The experiment may, however, be made by using charcoal, or a fragment of narrow glass tube, &c., as the support.) A. The flame is tinged strongly yellow. Sodium in some form is indicated. B. Blue. a. Chloride of Copper (ATACAMITE) colours the flame at first intensely blue, afterwards greenish. b. Bromide of Copper. This is very rare. c. Arsenic. This is a pale blue. d. Antimony. This gives a pale greenish-blue. e. Lead. Bright blue. f. Selenium. Intense blue. These substances are easily distinguished from each other by Exps. 1, 2, 3. 0. Green. a. Baryta and its compounds. Yellowish -green. b. Molybdenum and its compounds. Yellowish-green, c. Copper and its compounds, except the chloride. d. Telluric anhydride. This is very rare. e. Phosphorus and compounds. Pale bluish-green. f. Boric Acid or Anhydride. D. Red. a. Lithia. Very intense crimson, b. Strontia. Crimson. c. Lime. Brick red. E. Violet. Potash, This tint is often overpowered by the presence of the yellow flame of soda, but it may always be detected by looking through a piece of deep blue glass, which completely absorbs the yellow- without interfering with the violet rays. Many of the above flame colourations are well brought out by the appli- cation of a drop of hydrochloric acid, applied to the powder before heating. For phosphorus and phosphates sulphuric acid affords the most delicate reactions. TABLE IX. REACTIONS WITH SOLVENTS. A. Water. Very few minerals are soluble in water. Those that occur in Cornwall and Devon are : Melanterite, Johannite, Goslarite, Cyanosite, Kalinite, Halite. A large number of artificial products are soluble in water, including nearly all nitrates, acetates, and oxalates, chlorides (except those of lead, mercury, and silver), many sulphates, the carbonates and oxides of the alkalies, &c. B. Hydrochloric acid, dilute or concentrated, gently warmed if necessary, a. With effervescence. CHAPTER II. DETEEMINATIYE. 11 1. The gas evolved has little or no smell, and if conducted into "lime water" yields a white precipitate. The carbonates of lime, magnesia, manganese, iron, and most other carbonates behave thus. 2. The gas evolved has a strong sulphureous odour. Many sulphite* and hypo-sulphites behave thus. 3. Odour resembling that of rotten eggs. Many sulphides, b. Without effervescence. Silicates containing only a small proportion of silica, silicates of the alkalies, &c. These usually leave a gelatinous or slimy deposit of silica undissolved. C. Nitric Acid ; dilute or concentrated ; warmed if necessary. Substances having a metallic lustre should be treated with nitric acid, when they will often be dissolved or decomposed; red nitrous fumes being at the same time given off from the acid. D. Aqua Regia, concentrated and warmed, in cases where nitric acid and hydrochloric acid have both failed. Gold, Platinum, and many other substances, which are scarcely, or not at all, acted upon by HC1 or HNO 3 , are readily decomposed by Aqua Regia. E. Special solvents. a. Sulphuric Acid. Not often necessary, but useful for some few minerals. b. Ammonia. Chloride of Silver and Chloride of Copper are readily soluble in ammonia. c. Caustic Potash. Opal and some other minerals are partially or completely dissolved in Potash. d. Hydrofluoric Acid. Useful for the solution of silica and all silicates. The substance having been brought into solution will be in a fit state for examination according to the methods described in all works on qualitative analysis. Valuable information may, however, be often obtained from the colour of the solution. Thus, if it be BLUE, Copper is probably present. GKEEN, Nickel, Iron, or Manganese. PINK, Cobalt or Manganese. YELLOW or BROWN, Gold, Iron, Platinum, or Chromium. A good deal of information may also be gained by observing the colour, appearance, &c., of the substance when powdered. Thus if it be A. BLACK, and comparatively heavy, one or more of the oxides of Manga- nese, Copper, Iron, Nickel, or Cobalt ; or of the sulphides of Mercury, Silver, Copper, Bismuth, Lead, Antimony, Iron, Cobalt, Nickel, &c., may be present. B. BLACK, and very light, Carbon in some form. C. BROWN, Peroxide of Iron, or Sulphide of Tin, &c. D. RED, some oxides of Mercury, Lead, Iron, Copper, &c.; Sulphides of Mercury or Arsenic ; Iodide of Mercury ; Chromate of Potash, Ferridcyanide of Iron, Perchloride of Platinum, &c. , may be present. E. YELLOW, Chromates of Potassium, Sodium, Ammonium, Barium, Stron- tium, Calcium, Bismuth, Lead, &c.; Sulphides of Cadmium, Arsenic, Tin, &c.; Oxides of Lead, Tin, Bismuth ; Ferrocyanide of Potassium ; Iodide of Lead, &c. F. GREEN, Oxide of Mercury ; many salts of Iron, Copper, Nickel, Chro- mium ; Manganates of Potash and Soda, &c. G. BLUE, Salts of Copper ; anhydrous Salts of Cobalt, Phosphate of Iron, Prussian Blue, Ultramarine, &c. H. WHITE or COLOURLESS. Absence of either of the above in any con- siderable quantity; probable presence of silica or silicates, or most salts or oxides of the alkalies or alkaline earths, or of Zinc ; Chlorides of Mercury, Silver, Lead ; Carbonates of Lead, Bismuth ; very many organic substances, &c. The foregoing tables, I. to IX., form a suitable method for the "preliminary examination " of all substances, previous to their detailed analysis, whether natural or artificial, inorganic or organic. 12 CHAPTER II. DETERMINATIVE. It is seldom, however, that the nature of a substance is altogether unknown, and with the limited number of minerals in the district under consideration, a great deal of time may often be saved by using the following scheme, in which the minerals are grouped solely in accordance with their most evident characters, and those the least likely to be misunderstood. Sometimes a mineral appears in two or more groups, so as to afford a greater chance of its recognition ; nevertheless, to ensure success, the characters of a specimen should be compared with those of the groups in their order. TABLE X. MINERALS OF CORNWALL AND DEVON, ARRANGED IN GROUPS FOR CONVENIENCE OF IDENTIFICATION. GKOUP I. PULVERULENT. (Occurring in soft earthy masses, or as a powdery coating on other minerals.) Name. Colour. Behaviour on Charcoal B. B. In Borax Bead. Remarks. Black Sulpliuret Black. Easily reduced to a _ Very rare indeed. of Silver. bright white bead of See Argentite, silver. p. 9. Condurrite, Do. Easily reduced to a bead Green OF, red Very rare & local. of copper, with strong & opaque RF. See Domeykite, alliaceous odour. p. 42. Melaconite. Do. Easily reduced to a bead Do. Not uncommon in of copper, without alli- copper mines. aceous odour. Asbolane. Do. Infusible. Blue, both OF Very rare & local. and RF. Wad. Do. Do. Amethystine Local, but not OF, colourless RF. very rare. Pyrolusite. Do. Do. Do. Anhydrous, only the outer coating pulverulent. Red Ochre. Red. Do. Reddish-yellow Common in some OF, bottle- distsrict. See green RF. Hematite, p. 55. Umber. Brown. Do. Do. Do. See Limonite. p. 63. Yellow Ochre. Yellow. Do. Do. Do. do. Blue Iron Earth Blue. Fusible to a magnetic Do. Local & rare. See mass. Vivianite, p. 104. Pitticite. Yellow to Do. Do. Rather rare and brown. very local. Plumbic Ochre. Yellow. Easily reduced to a bead Very rare. of lead. Bismite. Do. Easily reduced to a bead Very rare. of bismuth. Cervantite. Do. Easily reduced to a brit- Not uncommon ; tle bead of antimony. but local. Wolframite. Do. Infusible and not re- Occurs as a coat- ducible. ing on Wolfram. Local and rare. Zippseite. Yellow or Do. Green bead OF Local and rare. grnsh-yel. and RF. Langite. Blue or Easily reduced to a bead Green OF, red Local and rather greenish. of copper. & opaque RF. rare. Annabergite. Green. Fusible, with strong al- Local and very liaceous odour. rare. Chlorite. Dark green Generally fusible to a Reddish-yellow Compact, massive or blue. magnetic mass. OF, bottle- very common. green RF. (Peach.) Kaolin. White. Infusible; blue with Co. Local ; very com- mon. Magnesite. Do. Infusible ; pink with Co. Very doubtful as ! Sol. eff. with a Cornish or De- von species. Meeolite. Do. j Fusible to a white ena- Very rare and mel ; blue with Co. local. CHAPTER II. DETERMINATIVE. 13 GROUP II. FOLIACEOUS. (Occurring in thin leaves or scales ; or may be easily split up into such with a penknife.) Name. Colour. Behaviour on Charcoal B. B. n Borax Bead. Remarks. Gilbertite. White or Infusible; blue with _ Local; chiefly in yellowish Co. china clay dis- tricts. Talc. VVhite or Infusible ; pink with Local ; with ser- Gypsum. greenish. White, yel- Co. Infusible ; fusible to a pentine. Local and rare ; lowish, or brownish clear bead with Fluor Spar. more often crys- tals with very easy cleav. than in thin plates. Goethite. Yellow or Infusible; hydrous. Reddish-yellow More often in dark brown. OF, bottle- coloured crys- green RF. tals. Hematite. Red,brown Infusible ; anhydrous. Do. Do. black. Brookite. Brown. Do. Yel. hot, violet cold RF. Exceedingly local and rare. Molybdenite. Lead grey. Infusible ; anhydrous ; Rare and local. turns flame greenish. Graphite. Do. Infusible ; anhydrous. Do. Marmolite. Green. Infusible ; pink with Local ; with com- Co. mon serpentine. Muscovite. Brown. Difficulty fusible (about Often occurs in 4); blue with Co. granite. cSchiller Spar. Yellow to Difficulty fusible. Occurs imbedded brown. in serpentine. Chlorite. Green. Difficulty fusible to a Reddish-yellow Very local in the magnetic mass. OF, bottle- foliated condi- green RF. tion. Lepidolite. White or Fusible ; tinges flame The white mica in peach. red if moistened with H 2 S0 4 . granite is chiefly Lepidolite. Lepidomelane. Brown or Fusible to a magnetic Reddish-yellow The dark mica in black. mass. OF, bottle- granite is chiefly green RF. Lepidomelane. Covellite. Dark blue. Fusible ; easily reduced Green OF, red Very rare. to a bead of copper. and opaque RF. Chalcophyllite. Green. Do. Do. Rare and local. Torbernite. Do. Fusible ; reduced with Do. Do. difficulty to a bead of copper on addition of soda. Autunite. Yellow. Fusible. Very rare & local. Vivianite. Green, blue Fusible to a magnetic Reddish-yellow Rare and local. or brown. mass. OF, bottle- green RF. Erythrite. Pink. Fusible ; strong allia- Blue, both OF Very rare & local. ceous odour. and RF. Copper. Red. Fusible; malleable. Occasionally found in thin leaves in the joints of serpen- tine and other rocks. Gold. Yellow. Fusible ; malleable. Very rare ; in stream works. 14 CHAPTER II. DETEEMINATIVE. GROUP III. -CAPILLARY. (Occurring in soft or flexible fibres.) Name. Colour. Behaviour on Char coal B. B. ' In Borax Bead Solubility. Remarks. Araenolite. White. Readily fusible Slightly Very rare. strong arsenica sol. in odour, and white water. coating. Goslarite. Do. Readily fusible at Soluble in Do. first, then infusi- water. ble ; green with Co. Kalinite. Do. Readily fusible at Soluble in Rare & local. first, then infusi- water. ble ; blue with Co. Mesolite. Do. Fusible to a white Soluble in A doubtful enamel; blue with HC1. species. Co. Natrolite. Do. Fusible ; blue with Slowly sol. Extremely Co. in HC1. rare. Tavistockite. Do. Do. . Do. Do. Asbestos. Do. Do. Insol. in Local, rather acids. rare. Actinolite. Green. Fusible. Do. Local. Silver. White, of- ten tar- Malleable, fusible to a bead of Silver - Soluble in HN0 3 . Very rare. nished. Cerussite. Do. Fusible ; easily re- Sol. eff. Local, not rare duced to Lead. HC1. Melanterite. Pale green. Fusible at first, then infusible. Reddish -yel- low OF, bot- Soluble in water. Local, rather rare, a pro- tle green duct of de- Aragonite. White to red or Infusible, alkaline after heating. RF. Sol. eff. in HC1. composition. Very rare and local. Gypsum. White to Infusible ; fusible Insol. in Rare. brown. with Fluor Spar to acids. a white bead. Chrysotile. White to Infusible ; pink Occurs with grey, with Co. serpentine in narrow veins Prehnite. Pale green. Fusible ; blue with Insol. in Very rare. Co. acids. Annabergite. Green. Fusible ; arsenical Green,sol. Do. odours. inHN0 3 . Atacamite. Do. Fusible ; bright Green OF, Soluble in Do. blue flame ; bead red and ammonia. of Cu. opaque RF. Olivenite. Greenish- Fusible, strong ar- Do. Sol. HC1. Rather rare grey. senical odour ; now. green flame. Connellite. Blue. Fusible, blue flame; Do. HN0 3 . Very rare. bead of Cu. Pyromorphite Green. Fusible ; crystal- Do. Not uncom. lizes on cooling ; in lead mines with soda a bead in small hex- of lead. ag. prisms, rarely acicu- lar. Mimetite. Yellow to Fusible ; strong ar- Do. Do. brown. senical odour ; bead of lead. Cervantite. Yellow. ?usible ; much Sol. HC1. Local, but not white fume. very rare. CHAPTER II. DETEKMINATIVE. 15 GROUP III. CAPILLARY (Continued). Name. Colour. Behaviour on Char- T _ [>__ T> j coal B. B. In Borax Bead Solubility Remarks. Erythrite. Pink. Fusible ; strong Blue, both HN0 3 . Rare. arsenical odours. flames. Chalcotrichite Red. Easily reduced to Green OF, Do. Rare & local a bead of copper. dark red in this form. and opaque See Cuprite, RF. p. 39. Millerite. Yellow and Fusible ; sulphure- Do. Rare. metallic. ous odour, brittle bead. Bismuthinite. Yellow or Fusible ; sulphure- Do. Do. grey, and ous odour : bead metallic. of Bismuth. Antimonite. Grey and Fusible ; much HC1. Local, not rare metallic. white fume. Jamesonite. Do. Fusible ; much Sol. in Do. white fume, and bead of lead. part. Wittichenite. Grey. Fusible ; bead of Green OF, HN0 3 . A doubtful copper. dark red species. RF. Vivianite. Green to Fusible to a mag- Reddish -yel- Do. Rare. brown. netic mass. low OF, bot- tle green RF. Tourmaline. Very dark Do. Do. Insol. Very common green, but not usu- brown, or ally acicular. black. Manganite. Greyish- Infusible. Amethystine HC1. Rare. black, me- OF, colour- tallic. less RF. Pyrolusite. Do. Do. Do. Do. Local but com- mon, usually acicular. Sulphur. Yellow. Combustible, blue Insol. Very rare in flame. Corn. orDev. GROUP IV. SAPID. (Soluble in water, and consequently having a distinct taste.) Name. Colour. Taste. Special Experiments. Remarks. Halite. White or Taste of com- Precipitates Mtrate of A doubtful Corn- brownish mon salt. Silver. ish or Devon species. Goslarite. White. Nauseous, me- With Co. green. Very rare. tallic. Arsenolite. Do. Sweetish. Alliaceous odour on Very rare ; en- charcoal. tirely volatile. Kalinite. Do. Sweetish, as- Blue with Co. Very rare. tringent. Melanterite. Pale green. Nauseous, like With borax, iron reac- Local, but not un- ink. tions. common. Cyanosite. Johannite. Blue or greenish. Green. Very nauseous, On charcoal a bead of metallic. Copper. Bitter, astrin- With borax, Uranium Not uncommon in copper mines. Very rare. 16 CHAPTER II. DETEEMINATIYE. GROUP V. MALLEABLE. (May be beaten out into thin plates without breaking under the hammer.) Name. Colour. Special Experiments. Remarks. Gold. Yellow. Insoluble in HC1 or HN0 3 ; Very rare. yellow solution in Aqua Regia. Silver. White, often Soluble in HN0 3 ; precipi- Rare. tarnished. tated by HC1 as a white curd, which is sol. in am. Copper. Argentite. Red. Lead-grey. Green solution in H]ST0 3 . On charcoal a bead of Common. Rare ; only imperfectly Silver. malleable. Chalcocite. Do. On charcoal a bead of Common ; only imperfectly Copper. malleable. Bismuth. Reddish-white. Fusible on charcoal, a red- Rather rare ; only imper- Molybdenite. Lead-grey. dish-yellow coating. Infusible, tinges flame fectly malleable. Flexible, usually folia- green. ceous ; rare. Kerargyrite. Greyish. Fusible, yields a bead of Rare. silver ; sol. in ammonia. GKOUP VI. PLASTIC. (May be moulded by the fingers, at least when wet.) Name. Colour. Special Experiments. Remarks. Kaolin. Chloropal. Glauconite. Smectite. Saponite. White. Yellowish-green Green. Brownish. Greyish or yell. Infusible ; blue with Co. Infusible ; turns black and magnetic. Fusible to a dark magnetic glass. Infusible, or fusible to a dark magnetic glass. Difficultly fusible. Very common. Not uncommon ; associated with china clay. A doubtful Cornish or Devon species. Falls to powder if placed in water ; a very doubt- ful species. See Steatite, p. 86. GROUP VII. BOTH COLOUR AND STREAK BLUE. Name. Behaviour on Charcoal. Solubility. Remarks. Chessylite. Readily yields a bead of copper. Soluble withe/. in HC1. Not uncommon in small quantities in cop. mines. Clinoclase. Strong alliaceous odours, and yields a bead of cop- Soluble, except the arsenic, in Rare ; may be best known by the form of its crys- per, more readily on addi- HN0 3 . tals. tion of soda. Liroconite. Do. Do. Do. Connellite. Yields a bead of copper ; strong sulphureous odour ; Not readily so- luble in acids. Exceedingly rare ; only a few specimens known. bright blue flame. Langite. Yields a bead of copper, Do. Rare ; occurs as a powdery with sulphureous odour. coating, or crystalline, on killas of copper lodes. CHAPTER II. DETEEMINATIVE. 17 GROUP VII (Continued). Name. Behaviour on Charcoal. Solubility. Remarks. Demidoffite. Infusible ; with soda yields Slowly decom- Extremely rare. a bead of copper. posed by HC1 leaving gela- tinous silica. Linarite. Fusible ; yields a small Insoluble in Extremely rare ; the streak grain of copper, and depo- acids. is very pale blue. sits a yellow coating of oxide of lead. Chlorite. Fusible to a magnetic bead. Do. Usually earthy or folia- ceous, and often more or less green. Blue Iron Earth. Do. Soluble in HC1. Pulverulent; rare. GROUP VIII. BOTH COLOUR AND STREAK GREEN. Name. Behaviour on Charcoal. Solubility. Remarks. Atacamite. Easily reduced to a bead Soluble in ammo- Very rare and local. of copper ; colours flame nia, colouring it strongly blue. strongly blue. Brochantite. Easily reduced to copper ; Soluble in HC1. Rare and local. sulphureous odour. Malachite. Reduced to copper with- Soluble with effer- Common in cop. mines ; Chrysocolla. out fluxes. Reduced to copper only by addition of fluxes. vescence in HC1. Slowly decomposed by HC1, leaving gelatinous silica. streak very pale green. Rare in copper mines ; not uncommon in the Lizard district ; streak very pale green. Olivenite. Fuses readily, sometimes deflagrates ; gives off al- Soluble, except ar- senic anhydride, Local, but not very rare. liaceous fumes, and de- in HJSTO 3 ; soluble posits an abundant in HC1, forming a white incrustation on green solution. the cool part of the sup- port ; with soda yields a bead of copper. Chalcophyllite. Do. Do. Rare ; best known by the form of its crystals. Clinoclase. Do. Do. Rare and local ; best dis- tinguished from Oli- venite by the form of its crystals ; more of- ten blue than green. Liroconite. Do. Do. Rare ; only green occa- sionally ; best distin- guished by the form of its crystals. Cornwallite. Do. Do. Very rare ; never in crystals. Erinite. Do. Do. ' Very rare ; occurs in mammillated crusts. Bayldonite. Fuses readily, gives off al- Soluble in warm Very rare ; occurs in liaceous odours, and de- HN0 3 , but not minute mammillary posits a yellow coating near the assay ; leaves a readily ; the solu- tion yields a white concretions ; grass- green to blackish- hard white alloy of cop- per and lead. ppt. of PbS0 4 on addition of sul- greeo. phuric acid. 18 CHAPTER II. DETERMINATIVE. GROUP VIII. (Continued.) Name. Behaviour on Charcoal. Solubility. Remarks. Chenevixite. Fuses readily to a black Readily soluble in Very rare ; occurs in magnetic scoria; gives HNO 3 or HC1, small compact masses, off arsenical fumes ; with fluxes yields a grain of forming a green solution. imbedded in quartz. copper. Libethenite. Fuses to a dark bead of Readily soluble in Rare and local. metallic appearance ; in HNOg, soluble RF with soda yields a also in HC1 or am- bead of copper, but not monia ; decom- readily. posed by KHO. Lunnite. Do. Do. Only one British speci- men known. Torbernite. Fuses to a dark mass, Soluble in HN0 3 . Local, but not rare, usu- which crystallizes on ally in very thin crys- cooling ; with soda talline plates. yields a bead of copper. Pyromorphite. Fuses readily, crystallizes Soluble in HNO S , Not uncommon in lead on cooling ; with soda the solution yields mines; usually occurs yields a bead of lead, and a white ppt. on in minute hexagonal coats the support yel. addition of H 2 prisms of a green S0 4 . colour ; streak often uncoloured. Pharmacosi- Fuses readily to a black Soluble in HN0 3 Rare and local ; usually derite. magnetic mass, giving orHCL occurs in minute green- off arsenical odours ; ish cubes, variously with borax yields iron modified. reactions. Scorodite. Do. Do. Very rare and local ; usually occurs in slen- der prisms of a pale bluish-green colour ; streak nearly colorless. Vivianite. Fuses readily to a dark Do. Local, but sometimes magnetic mass, which not uncommon ; very yields iron reactions variable in colour, but with borax. powder always blue after a little exposure. Cronstedtite. Fuses to a magnetic mass ; with borax yields iron Slowly decomposed by HC1, leaving Very rare and local. reactions. gelatinous silica. Annabergite. Fuses readily, giving off Soluble in HC1 or Local and rare. strong alliaceous odours HNOq, forming a with borax yields nickel : clear green solu- reactions. tion. Chlorite. Fusible to a magnetic bead Insoluble in acids. Com., but usually earthy. GROUP IX. COLOUR AND STREAK KED, YELLOW, OR BROWN. Name. Hard- ness. Streak. Behaviour on Char- coal. Solubility. Remarks. Cervantite. Bleinierite. Soft. 2-0-4-0 Yellow. Do. Volatile OF; re- duced to a bead of antimony RF. Fuses readily to a grey brittle glo- bule with sulphu- reous odour. Sol. in HC1, sometimes re-precip. on addition of water. Sol. in strong HC1, giving offH 2 S, Local, but not very rare. Do. CHAPTER II. DETEKMINATIVE. 19 GROUP IX. (Continued.) Name. Hard- ness. Streak. Behaviour on Char- coal. Solubility. Remarks. Pharmacosi- 2-5 Pale brown Fuses readily to a Sol. in HC1 Rare & local, derite. to green. dark magnetic mass, giving off al or HN0 3 . usually in small green- liaceous odours ish cubes. with borax yields iron reactions. Pitticite. 2-3 Yellow or Do. Sol. in HC1. Local, but brownish. sometimes not very rare A product of the decomp. of other mi- nerals in old works; never crystallized. Goethite. 5-5-5 Do. Infusible ; with Slowly sol. in Loc., but not borax yields iron HC1. rare ; occurs reactions. usually in dark brown bril. crystls. Limonite. Do. Yellow or brown. Do. Do. Very com., oft. radiated but never in crystals ;yel. ochre is soft. Anatase. 5-5-6 Pale brown. Infusible ; with Slowly sol. in Very rare & borax yields tita- concentrat. local. nium reactions. H 2 S0 4 ; in- sol. in HC1 or HN0 3 . Rutile. Do. Do. Do. Do. Do. Brookite. Do. Do. Do. Do. Do. Titanite. 5-5-5 Greyish or Very slightly fusi- Decomposed Do. brownish. ble. by HC1. Olivenite. 3 Pale brown to green. Fuses readily, and gives off alliace- ous odours ; with Sol. in HC1, & all except arsenic an- Local but not very rare. soda yields a bead hydide in of copper. HN0 3 . Hisingerite. 3-5-4 Yellow to Fuses to a dark Soluble, ex- Local & rare. brown. magnetic bead, but not readily. cept silica, in HC1. Pyromorphite. Do. Pale brown. Fuses readily to a Sol.inHN0 3 , Not uncom. bead which crys- precip. by in lead mines tallizes on cool- H 2 S0 4 . cob?, usually ing ; Avith soda green, streak yields a bead of pale green. lead. Autunite. 1-2-5 Yellow. Fuses readily to a Sol.inHN0 3 , Local & very dark mass with forming a rare; usually crystalline surface yellow solu- as yellow tion. scales. Blende. 3-5-4 Pale brown. Infusible ; decrepi- tates strongly ; Very slowly soluble in Very com,, and widely support often slightly coated H 2 S0 4 , giv- ing oft' H 2 S. diffused. Avith Avhite. Wolfram. 5-5-5 Dark brown. Infusible, or diffi- Slowly de- Loc., but not culty fusible ; de- crepitates strong- composed byHCl, de- rare; usually imbedded in ly. positing yel. quartz or tungstic an- chlorite. hydride. 20 CHAPTER II. DETEKMINATIVE. GEOUP IX. (Continued.) Name. Hard- ness. Streak. Behaviour on Char- coal. Solubility. Remarks. Retinite. 1-2-5 Pale brown. Burns with a bright flame. Partly sol. in alcohol or In England found only ether ; insol. at Bovey in acids. Tracey. Cuprite. 3-5-4 Red or dark brown. Easily reduced to a bead of copper. Sol, in HN0 3 , forming a Common. green solu- tion. Hematite. 5-5-6-5 Do. Infusible ; magne- Slowly sol. in Do. tic ; with borax HC1. gives iron reac- 1 tions. Erythrite. 1-5-2-5 Pink. Fusible readily ; Sol. in HC1 or Local & rare. gives off alliace- HN0 3 . ous odours ; with borax yields co- balt reactions. Pyrargyrite. 2-2-5 Dark red. Fuses readily to a Decomp. by Do. dark bead ; after HNOg, pre long roasting; cipitatedon yields a bead of; addition of silver. HC1. GROUP X. COLOUR VARIOUS, STREAK BLACK OR VERY DARK, H. BELOW 5. (Easily scratched with a knife.) Name. Colour. Streak. Sp. Gr. Behaviour on Charcoal. Solubility. Remarks. Antimonite. Lead-grey. Black. 4-5-4-7 Readily fusible; Soluble in Common, volatile ; sulphu- wannHCl, but local. reous odour ; gives off white coating. H 2 S. Jamesonite. Do. Do. 5-5-5-8 Readily fusible ; Soluble in Common, sulph. odour ; HN0 8 ,pre- but local. yellow coating ; cipitated bead of lead. by H 2 SO 4 . Antimony. Tin-white. Grey and 6-6-6-8 Readily fusible & Soluble in A doubtful shining. volatile ; white Aqua Reg. British coating. species. Arsenic. Dark grey- Do. 5-9-6-0 Readily fusible & Soluble in Do. ish. volatile; strong HC1. alliaceous odour. Berthierite. Grey or brown. Dark grey or black. 4-4-3 Readily fusible to a dark magnetic Sol.inHCl, giving off Local, but probably slag ; white coat- H 2 S. not very ing ; sulphureous rare. odour. Argentite. Lead-grey. Black, 6-9-7-4 Readily fusible& Soluble in Local and shining. reduced to a bead HNO s ,pre- rare; mal- of silver. ciptd. by leable. HC1, color- less solutn. Stephanite. Black. Black. 6-2-6-3 Readily fusible; white coating on As Argen- tite, color- Local and rare; brit- support ; bead of less solu- tle. silver if treated tion. with soda. CHAPTER IL DETERMINATIVE. 21 GROUP X. (Continued.) Name. Colour. Streak. Sp. Gr. Behaviour on Charcoal. Solubility. Remarks. Polybasite. Black. Black. 6-0-6-2 Readily fusible; As Argen- A doubtful white coating ; tite, green British bead of Ag. with soda. solution. species. Chalcocite. Lead-grey. Greyish- black. 5-5-5-8 Keadily fusible; bead of copper ; Decompsd. by Htf0 3 , Common, but local. sulph. odour. green solu- tion. CoveUite. Dark blue. Black. 3-8-4-6 Keadily fusible; As Chalco- Local and combustible in cite. rare. part ; bead of per ; sulphure- ous odour. Erubescite. Purplish, mottled, or Do. 4-4-4-5 As Chalcocite, but requires ad- Do. Local, but not un- variegated. dition of borax common. for reduction ; slag gives iron reactions. Chalcopy- Yellow or Greenish- 3-5-4 As Erubescite ; Do. Common. rite. variegated. black. but less easily reduced to cop- per ; fused mass is magnetic. Domeykite Greyish or Black and 4-5-7'5 Fuses readily ; Partially Local and (Condur- brownish- shining. yields strong al- soluble in rare. rite). black. liaceous odour & abundant white HNO ? ,grn. solution. coating ; reduced to a bead of cop. Tennantite. Lead - grey to iron- Dark red- dish-brown 4-3-4-5 Fuses readily ; strong alliaceous As Domey- kite. Local and rather black. odour ; white rare, oc- coating ; bead of curs usu- cop. with fluxes. ally in minute tetrahed. crystals. Fahlerz. Grey to Dark red- 4-5-5-2 Fuses readily ; Very much Local, but iron-black dish-brown white coating ; as Tennan- not very often iri- or black. usually no allia- tite. rare. descent. ceous odour ; bd. cop. with fluxes. Bournonite. Lead-grey. Greyish- 57-5-9 Fuses readily ; Partially Local, but black. sulphureous sol. in hot not very odour ; yellow i HNO^ ; a rare ;very coating; bead of white ppt. brilliant. cop. with fluxes. on addi- tion of H 2 S0 4 . Stannite. Greyish or Black. 4-3-4-6 Fuses readily to Decompsd. Local, but black. a brittle magne- by hot not rare. tic bead; white HN0 3 ,grn. coating ; sulphu- solution. reous odour. Wittiche- Tin -white Do. 4-3-5 Fuses readily ; Soluble in A doubtful nite. to steel- dark yellow coat- hotHN0 3 ; British grey. ing ; sulphure- white ppt. species. ous odour ; bead if diluted of copper with with much difficulty. water. 22 CHAPTER II. DETEEMINATIYE. GKOUP X. (Continued.) Name. Colour. Streak. Sp. Gr. Behaviour on Charcoal. Solubility. Remarks. Bismuthi- Lead- grey, Black. 6-4-6-6 Fuses readily ; Decompsd. Local and nite. often a dark yellow coat- by hot rare ; ge- yellow tar- ing ; sulphure- HNOspre- nerally in nish. ous odour ; brit- cipitated brilliant tle bead of bis- by water. needles. muth. Galena. Lead-grey. Do 7-2-77 Fuses readily ; Decompsd. Common. sulph. odour ; by hot bead of lead. HN0 3 . 1'entlandite Bronze-yel- Dark 4-6 Fuses readily to Soluble in Local and low or brown. a dark brittle HNC-3, rare. brownish. magnetic mass ; forming a with borax yields greenish- iron reactions ; yellow so- sulph. odour. lution. Wolfram. Dark grey- Do. 7-7-6 Infusible, or fusi- Decompsd. Local, but ish, or ble with great by Aqua not rare brownish - difficulty ; decre- Regia, de- usually ; black. pitates strongly. positing more than yel. tungs- tic anhyd. 5-0. Manganite. Greyish- Dark 4-2--1-4 Infusible ; Mn Soluble in Local and black. brown or reactions with warmHCl. rath, rare black. borax. Pyrolusite. Bluish- Black. 4-7-5-0 Do. Soluble in Local, but black. warm HC1, rather giving off common ; H 2 S. soils the fingers. GROUP XI. COLOUR VARIOUS; STREAK BLACK OR VERY DARK; H. FROM 5 TO 6. (Scratched with a knife, but not easily.) Name. Colour. Streak. Sp. Gr. Behaviour on Charcoal. Borax Bead. Remarks. Chromite. Brownish- Brown. 4-4-4-5 Infusible. Green both Local and black. flames. rare, in grains imbedded in serp. Cobaltite. Tin - white Greyish- 6-6-3 Fusible to a dark Blue, both Local and or red- black. brittle magnetic flames. rare. dish. bead ; alliaceous and sulphureous fumes. Smaltite. Greyish- Black. 6-4-7-7 Fusible to a dark Do. Not un- black. brittle magnetic common. bead ; alliaceous odour and white coating. Mispickel. Tin -white Do. 6-6-3 Fuses readily to Reddish- Common to steel- a dark brittle yellow OF, in tin grey. magnetic bead; bottle- mines. alliaceous and green RF. sulph. odours ; white coating. CHAPTER II. DETEKMINATIVE. 23 GEOUP XL (Continued.) Name. Colour. Streak. Sp. Gr. Behaviour on Charcoal. Borax Bead. Remarks. Leucopyrite Tin -white, Black or 6 '9-7 '4 Fuses readily to As Mispic- Not un- often a greyish. , a magnetic bead ; kel. common brown strong alliace- in tin tarnish. ous odours. mines. Magnetite. Dark brown Black. 4-9-5-2 Infusible. Do. Local and or black. rather rare, of ten strongly magnetic. Ilmenite. Steel - grey or black. Brown to 4 -6-5-0 black. | Do. Yellow OF, brown RF. Local, but not very rare. Psilomelane Greyish- Brownish- 5-6 Do. Amethyst- Local, not black. black and ine OF, uncom. shining. colourless RF. Niccolite. Copper-red Brownish- 6-6-7-3 Fuses easily to a Variable ; Local and black. brittle globule ; reactions rare. strong alliace- for nickel ous odours. and iron. Wolfram. Dark grey- Dark brown 7-7-6 Infusible, or fusi- Reddish- Local, but ish or ble with great yellow OF, not rare. brownish- difficulty ; decre- darker on black. pitates strongly, cooling. and separates in- to thin scales. GROUP XII. COLOUR VARIOUS; STREAK WHITE OR VERY LIGHT; H. BELOW 5. (Easily scratched with a knife.) Name. Sp. Gr. Behaviour on Charcoal. Solubility. Remarks. Anglesite. 6-1-6-4 Fuses easily ; sulphure- Infusible in acids. Local and rare. ous odour ; bead of lead. Cerussite. 6-4-6-5 Easily reduced to a Soluble with effer- Local, but not bead of lead. vescence in HC1 very rare, usu- or HN0 3 . ally acicular. Cromfordite. 6-6-3 Fuses easily to a white Partly soluble with Only one Cornish globule, which crys- effervescence in specimen known tallizes on cooling ; in HN0 3 . to have occurred RF a bead of lead and Mimetite. 7-7-3 white coating. Fuses easily ; strong alliaceous odour and Partly soluble in HN0 3 . Local, but not un- common in lead bead of lead. mines. Pyromorphite. 6-5-71 Fuses easily ; crystal- Do. Not uncommon lizes on cooling ; with in lead mines. borax yields a bead of lead, but not easily. Bismuth. 9-6-9*8 Very readily fusible ; Soluble in HN0 3 ; Local, but not coats support yellow. precipitated on addition of water. very rare. 24 CHAPTER II.DETEEMINATIYE. GEOUP XII. (Continued.) Name. Sp. Gr. Behaviour on Charcoal. Solubility. Remarks. Agnesite. 6-9-7 Very readily fusible ; Soluble (with effer- Local and very yellow coating ; grey ves.?) in HN0 3 ; rare. brittle bead of bis- precip. on addi- muth. tion of water. Valentinite. 5-5-5-6 Fusible and volatile ; Soluble in Aqua Local and rare. white coating, no al- Regia, re-precip. liaceous odour. on addition of water if concen- trated. Senarmontite. 5-2-5-3 Do. Do. Do. Olivenite. 3-9-4 Readily fusible ; strong Soluble in HN0 3 Local, but not alliaceous odour, white coating ; bead except As 2 3 . very rare ; streak usually very of copper if treated light green. with soda. Pharmacoside- 2-9-3 Readily fusible ; allia- Mostly soluble in Local and rare ; rite. ceous odour, white occurs usually in coating; brittle mag- minute cubes of netic slag which gives iron reactions. a green colour. Scorodite. 3-1-3-3 Much like the preced- Do. Local and rare ; ing. occurs usually in very light green prisms. Vivianite. 2-6-2-7 Fuses readily to a dark Do. Local, but not magnetic bead ; with very rare; streak borax yields iron reac- soon becomes tions. blue, though white at first. Wavellite. 2-3-2-4 Fuses to a white opaque Soluble in HC1 and Local, but not mass which turns blue HN0 3 . very rare, usual- when treated with Co. ly in radiated masses. Natrolite. 2-2-2-3 Fuses readily, colours Decomposed by Very rare. flame yellow, white HC1, leaving gela- residue, blue with Co. tinous silica. Stilbite. 2-2-2 Do. Do. Do. Asbestos. 2-9-3-4 Fusible, but not readi- Insoluble in HC1. Not uncommon in ly ; usually turns blue some districts. with Co. Schiller Spar. 2-6-2-8 Fusible, but not readi- Decomposed by Not uncommon in ly ; pinkish if treated with Co. H 2 S0 4 , less readi- ly by HC1. serpentine. Serpentine. 2-4-2-6 Do. Do. Very common in some districts. Agalmatolite. 2-4-2-9 Infusible ; blue with Co. Decomposed by Local, but not warm H 2 SC>4 ; very rare. scarcely acted upon by HC1. Chiastolite. 2-9-3-4 Do. Insoluble in HC1 or A doubtful Corn- HN0 3 . ish species. Pinite. 27-2-9 Infusible, or fusible Slightly acted on Local, but not with great difficulty; by HC1. uncommon. blue with Co. Allophane. 1-8-1-9 Do. Decomposed by Local and rare. HC1. Schrotterite. 1-9-21 Infusible, or fusible Decomposed by A doubtful Corn- with great difficulty ; HC1. ish species. blue with Co. Steatite. 2-2-2-8 Infusible ; pink or red Scarcely affected Local, but not with Co. by HC1, decom- uncommon. Talc. 2-6-2-8 Do. posed by H 2 S0 4 . Do, Do. CHAPTER II. DETEEMINATIVE. 25 GROUP XII. (Continued. ) Name. Sp. Gr. Behaviour on Charcoal. Solubility. Remarks. Magnesite. 2-8-3-1 Infusible ; pink with Soluble with effer- A doubtful Corn- Co. vescence in HCL ish species. Blende. 3-9-4-2 Infusible ; decrepitates Soluble in strong Very common. strongly ; sulphureous HC1 or HX0 3 ; odours, often white gives off H a S. coating, which turns green with Co. Calamine. 4-4-5 Infusible ; green with Soluble with effer- Local and rare. Co. vescence in HC1. Calcite. 2-5-2-8 Infusible ; glows with a Soluble with effer- Not uncommon. bright light ; becomes vescence in dilute alkaline. HC1. Aragonite. 27-3-0 As Calcite, but falls to Do. Very rare and powder at a low tem- local. perature. Dolomite. 2-8-31 Infusible; becomes al- Do. Not uncommon. kaline. Chalybite. 37-3-9 Infusible, but turns Slowly soluble in Very common. black and magnetic. HC1, with efferves- cence. Barytes. 3-4-7 Fusible at about 3 ; Insoluble in HC1 Local, but not tinges flame yellow- until after heat- very rare. ish-green. ing in RF. Celestite. 3-8-4 Fusible at about 3 to a Do. Local and rare. white mass ; if mois- tened with HC1 co- lours flame bright red. Chrysocolla. 2-2-2-3 Infusible ; with soda Soluble in HC1, Local, but not effervesces and yields leaving gelati- very rare. a bead of copper. nous silica. Chloropal. 17-2-1 Fusible with difficulty Decomposed by Do. or infusible ; turns HC1, leaving ge- black and magnetic. latinous silica. Churchite. 3-0-3-1 Infusible ; becomes Very rare. opaque. GROUP XIII. COLOURS VARIOUS ; STREAK WHITE OR VERY LIGHT ; H. FROM 5 TO 6. (Scratched with a knife, but not easily.) Name. Sp. Gr. Matrass. On Charcoal. Solubility. Remarks. Natrolite. 2-2-2-3 Yields water. Fuses readily ; Decomp. by Very rare. colours flame yel- HC1, leaving low, white resi- gelatinous due; blue with silica. Co. Analcite. 2-0-2-3 Do. Do. Do. Of very doubtful occurrence. Childrenite. 3-2 Do. Infusible ; with Slowly sol. in Local and rare. boraxyieldsiron HC1. reactions. Porcellanite. 2-6-2-8 Do. Fuses with some Slightly act- Of very doubtful difficulty ; blue ed upon by occurrence. with Co. HC1. CHAPTER II. DETERMINATIVE. GROUP XIII. (Continued.) Name. Sp. Gr. Matrass. On Charcoal. Solubility. Remarks. Babingtonite. 3-3-3-5 Anhydrous. Fusible ; alkaline Insoluble in Local, but not reaction after HC1 or very rare. heating ; with HN0 3 , borax iron reac- tions. Amphibole. 2-9-3-4 Do. Often fusible to Do. Not uncommon; a dark magnetic often green and mass. radiated. Pyroxene. 3-2-8-5 Do. Do. Do. Local, but not very rare. Orthoclase. 2-6 Do. Fusible with diffi- Do. Common in gra- culty, or infusi- nite ; cleavages ble. at right angles. Albite. 2-6-2-7 Do. Fusible ; colours Do. Probably not un- flame strongly common in gra- yellow. nite ; cleavage inclined. Scapolite. 2-6-2-8 Do. Fusible ; blue Do, Local and rare. with Co. Saussurite. 2-7-3-4 Do. Fusible with dif- Do. Local, but not ficulty, or infu- rare. sible. Apatite. 3-2-3-3 Do. Fuses with dif- Slowly sol. in Local and rare. ficulty, or infu- HC1 or sible. HN0 3 . Titanite. 3-4-3-6 Do. Do. Decomposed Do. by HC1 or HN0 3 . Scheelite. 5-9-6-2 Do. Do. Soluble, ex- Do. cept yellow tungstic an- hydride, in HC1. Rhodonite. 3-4-3-7 Do. Do. Soluble, ex- Local, but not cept silica, rare. in HC1. OROUP XIV. COLOURS VARIOUS ; H. = 6 AND UPWARDS. (Cannot be scraiched with a knife.) Name. Hard- ness. Sp. Gr. Common Colours of Cornish or Devonshire specimens. Remarks. Quartz. Calcedony. Jasper. 7 6-7 6-7 2-5-2-8 2-6 2-63 Often colourless, or white and opaque ; sometimes tinged pur- ple (A methyst), yellow (False Topaz), or brown ; rarely green. Often bluish or yellow- ish ; sometimes white and opaque on the outside, and nearly black within. Usually red, brown, or black, sometimes dark green. Very common ; best known hy its hardness, want of cleavage, and insolubility in all acids except HF ; often crystallized in hexagonal prisms. Much less common than quartz ; usually botryoidal or stalac- titic ; never crystallized ; usu- ally translucent, but not transparent. Not very rare ; never crystal- lized ; nearly or quite opaque. CHAPTER II. DETERMINATIVE. GROUP XIV. (Continued.) Name. Hard- ness. Sp. Gr. Common Colours of Cornish or Devonshire specimens. Remarks. Saussurite. 6 2-7-3-4 Usually greenish or Local, but not very rare ; in reddish. Britain not known out of the Lizard district. Orthoclase. 6 2-5-2-6 Usually pale flesh- Very common in granite ; best coloured ; pink or red known by its perfect rectan- sometimes. gular cleavages. Albite. 6-7 2-6-27 Usually white or cream- Less common than Orthoclase ; coloured. cleavages make angles of 93o 36' and 86 24'. Amphibole. 5-6 2-9-3-4 Usually dark green. Common in a massive condition ; rarely crystallized ; fusible more or less readily. Pyroxene. 4-6 3-2-3-3 Mostly dark green or Usually massive ; much less nearly black. common than Amphibole : re- ported from St. Just, but it is doubtful whether the typical variety has occurred in Corn- wall or Devon. Hypersthene. 4-6 3-2-3-6 Mostly dark brown. Reported from the Lizard dis^ trict, but it is doubtful whether true Hypersthene has been found there. Opal. 5'5-6-S 1-9-2-3 Mostly of light colours. Local and rather rare ; never crystallized ; yields water in matrass, and is partially solu- ble in KHO. Isopyre. 5'5-6-5 29-3-0 Usually dark brown or Local and rare ; not known, to nearly black. crystallize ; somewhat vitreous in appearance. Rhodonite. 5-6 3-4-3-7 Usually -pink or rose- Local, but not very rare, in a red. massive condition ; fusible with a strong heat, and yields manganese reactions. Tourmaline. 7-7-5 2-9-3-3 Usually black, dark Common ; usually in indistinct brown, or dark green. prisms, or radiated masses. Garnet. 6-5-7-5 3-1-4-3 Usually brown or Local and somewhat rare ; oc- brownish-yellow. curs in crystals like Figs. 3, 5, 19, 25, 26. Axinite. 6-5-7 3-3-3 Brownish. Best known by its unsymme- trical, sharp-edged, brilliant, tabular crystals ; local and somewhat rare. Anatase. 5-5-6 3-8-4 Mostly brownish ; lus- Local and rare ; best known by tre semi-metallic. the form of its crystals, see Figs. 72, 73, 234 ; with borax yields titanium reactions. Brookite. 5-5-6 4-4*2 Brownish ; thin plates Local and very rare ; crystals reddish ; lustre semi- like Fig. 147 ; with borax like metallic. Anatase. Rutile. 5-5-6 4-2-4-8 Brownish or reddish ; Local and very rare, or doubt- lustre semi-metallic. ful ; with borax like Ana- tase. Cassiterite. 6-7 6-8-7 Greyish, brownish, or Common ; easily known by its black ; lustre semi- hardness and high specific metallic. gravity. Pyrites. 6-6-5 4-8-5-1 Yellow ; lustre metallic. Common ; often occurs in cubes or pentagonal dodecahedrons. Marcasite. 6-6-5 4-8-5-1 Do. Not so common as Pyrites, best distinguished by the different form of its crystals. Braunite. 6-6-5 4-7-4-8 Black or dark-grey ; Very doubtful as a British spe- lustre metallic. cies ; with borax yields man- ganese reactions. 28 CHAPTER II. DETEEMINATIVE. GROUP XIV. (Continued.) Name. Hard- ness. Sp. Gr. Common Colours of Cornish and Devonshire specimens. Remarks. Chondrodite. 6-6-5 31-3-3 _ Very rare, if not doubtful ; occurs in small, highly modi- fied imbedded crystals. Topaz. 8 3-4-3-6 Colourless, or slightly tinted with blue, Local and very rare ; in longi- tudinally striated prisms, with green, or yellow. Cassiterite, Apatite, Fluor, or Quartz. Beryl. 7-5-8-0 2-6-2-8 Colourless, or slightly tinted with green or Local and very rare, as hex- agonal prisms, imbedded in blue. Granite. Prehnite. 6-7 2-9-3 Usually pale green. Local and very rare ; fusible with effervescence at about 3. Epidote. 6-5 3-3-5 Usually green or brown. Local and very rare : fusible more or less readily ; occurs imbedded in Quartz or on Hornblende rock. Andalusite. 7-7-5 2-9-3-4 Usually dull white or Local and very rare ; occurs in Staurolite. 7-7-5 3-4-3-8 greyish. Usually reddish-brown square prisms. Local and very rare, if not or black. doubtful. GROUP XV. COLOUR VARIOUS; COMBUSTIBLE OR VOLATILE. (If heated on Charcoal, burn away or pass off in vapour.) NOTE. Many sulphides take fire momentarily, but they always leave a considerable quantity of incombustible mutter. Name. Colour. Sp. Gr. Solubility. Remarks. Bitumen. Dark brown or 1-1-2 Partly soluble Local and rare ; usually black. in ether or more or less plastic. alcohol. Retinite. Brown or yellow- 1-1-2 Do. Local, not very rare ; brit- ish-brown. tle ; found only at Bovey Tracey. Arsenic.' Dark steel grey. 5-9-6-0 Soluble in HC1. A doubtful species. Arsenolite. White, or pale yel- 3-6-3-7 Do. Local and rare ; completely low. volatile. Graphite. Lead-grey or black. 1-8-2-0 Insoluble in acids. Local and rare ; burns away slowly without flame. Sulphur. Yellow. 2-2-1 Do. Local and very rare ; burns with sulphureous odour. Pigotite. Brown. Partly soluble Local, but probably not in HC1. 1 very rare. CHAPTER III. DESCKIPTIVE. 29 CHAPTER III. DESCRIPTIVE. A full description of a mineral would involve a knowledge of all its properties, as well as the conditions of its occurrence and the mode of its formation. In this sense no mineral has yet been described ; perhaps never will be. In the second part of this work I have endeavoured to indicate by the type in which the name is printed the comparative abundance or rarity of the minerals described. Thus, very common minerals, as PYRITES ; minerals which are less common, as CALCITE ; and those which may be regarded as rare, as OLIVENITE, are at once indicated by their type. A further distinction had been intended for the very rare ones, as TOPAZ, but by an oversight this was neglected until too late. The characters of the minerals are then given, as far as possible in the following order: Synonyms, Frangibility, Streak, Form, Diaphaneity, Phosphorescence, Cleavage, Lustre, Hardness, Structure, Colour, Specific Gravity. The best marked varieties are then described (Var.}, after which the chief blowpipe and chemical reactions are indicated (B., etc.). The chemical composi- tion (Comp.) is next given, together with all the analyses of specimens from Cornwall or Devon which the author has been able to procure. In most cases formulae of several kinds are added in accordance with a theoretical composition. The atomic weight and symbols used in the f ormulse are given in a " Table of the Elements," which closes this chapter. The localities (Loc.) are then stated as fully as possible, and certainly much more so than in any work previously issued. Especial care has been taken to avoid errors in this respect ; and it is believed that although there may be many omissions, very few of the localities stated are erroneous. In the West of Cornwall many are given from the author's personal knowledge. Next, a general indication of the extent of the distribution of the species is given ; then, often some simple means of distin- guishing it from minerals which it somewhat resembles, and mention is made of the minerals or rocks with which it is especially associated. A table of the angles of the crystals, with reference to the figures in Plates 1 to 10, is then given, for which the author is mostly indebted to Messrs. Greg and Lettsom's Manual of the Mineralogy of Great Britain and Ireland, with occasional aid from Brooke and Miller, Dana, and Nicol. In future discoveries of minerals the author would suggest to the discoverers that they should particularly observe the minerals with which the specimens are associated, and, if first seen in situ, that they should carefully observe the position of the crystals, with reference to the "foot-wall," " hanging- wall," or "back" of the lode, or the "joints" of the quarry. In some instances the names given to minerals have reference, either to some supposed peculiarity of the species, or of its mode of occurrence. I therefore give a list of those which occur in the district under consideration, with short remarks upon each. NOMENCLATURE OF MINERALS OCCURRING IN CORNWALL OR DEVONSHIRE. (NAMES OF VARIETIES IN ITALICS.) Actinolite. Gr. Actinotos, radiated ; lithos, a stone. AGALMATOLITE. (Gr. Agalma, an image ; lithos, a stone.) Figure-Stone. So called because it is carved into figures by the Chinese. Agate. Named from its occurrence near the river Achates, in Sicily. AGNESITE. So called because it was found at St. Agnes, Cornwall. ALBITE. (Lat. Alba, white.) First described by Wallerius, in 1747. 30 CHAPTER III. DESCEIPTIVE. ALLOPHANE. (Gr. Allos, different; phaino, I appear.) First described by Stromeyer, in 1816. Amethyst. (Gr. A, priv.; methystos, drunkard.) From its supposed virtue of preventing intoxication. Amianthus. (Gr. A, priv.; miaino, to soil.) In allusion to the method of cleaning fabrics made of this mineral by fire. AMPHIBOLE. (Gr. Amphibolos, doubtful or ambiguous.) In allusion to the resemblance of the different varieties, or sub-species, to those of Pyroxene. First described as a variety of Schorl, by Wallerius, 1747. ANALCITE. (Gr. A, priv.; alkimos, strong; lithos, a stone.) Discovered! by Dolomieu, at Etna, in 1784 ; named by Gallitzin, in 1801, in allusion to its feeble electric properties. ANATASE. (Gr. Anatasis, stretching forth.) First described by Rome de 1'Isle, in 1783, as a variety of Schorl ; named Anatase by Hauy, in 1801, in allusion to the frequent lengthened form of the pyramids. ANDALUSITE. First described (a specimen from Forez) in the "Journal de Physique," in 1789; named Andalusite, by Delameth, in the same journal, 1798, from its frequent occurrence in Andalusia. ANGLESITE. First described by Monnet, in 1779 ; named by Beudant, in 1832, from its occurrence in the Isle of Anglesea. ANNABERGITE. First described by Cronstedt, in 1758 ; named by Brooke and Miller, in 1852, from its occurrence at Annaberg. ANTHRACITE. Gr. Anthrax, carbon. ANTIMONITE. First described by Basil Valentine (who proved it to contain sulphur) in 1430 ; named Antimonite, by Haidinger, in 1845. ANTIMONY. Described Vet-Academineus, Stockholm, 1748. APATITE. (Gr. Apatao, I deceive.) First mentioned as a variety of Aqua- marine, by Brunnick, in 1770, and as a variety of Chrysolite, by Rome de l'Isle r 1772 ; named by Karsten, in the year 1800, in allusion to its great resemblance to many other minerals. ARAGONITE. First described by Davila, 1767 ; defined, separated from Calcite, on account of its crystallization, and named by Hauy, in 1801, from its occurrence in Aragon. ARGENTITE. (Lat. Argentum, silver.) First described by Agricola, 1529 ; named by Haidinger, in 1845. ARSENIC. Gr. Arsenikon, masculine.) In allusion to its very strong and well-defined properties. ARSENOLITE. First described by Wallerius, in 1747 ; named and defined by Dana, in 1854. Asbestos. Gr. A, priv.; sbestos, combustible. ASBOLANE. (Gr. Asbolaino, I soil like soot.) First observed in 1529 ; named by Breithaupt, in 1847. ATACAMITE. First described by Rochefoucauld, Baume, and Fourcroy, in 1786 ; named by Blumenbach, in allusion to its occurrence in the desert of Atacama, in 1805. Augite. Gr. Auge, lustre. AUTUNITE. Described as a variety of Uranite, before 1819, by several authors ; named by Brooke and Miller, in 1852, in allusion to its occurrence at Autun. AXINITE. (Gr. Axine, an axe.) First described as a species of Schorl, by Schruber, in 1781 ; named by Hauy, in 1779, in allusion to the common form of its crystals. Babel Quartz. Named, in allusion to the successive stories of which it is built up, after the Tower of Babel. BABINGTONITE. First described by Levy, in 1824, and na,med after Dr. Babington. BARYTES. (Gr. Barus, heavy.) First described by Licetus, in 1640; named Barytite by Delameth, in 1797, in allusion to its high sp. gr. BAYLDONITE. First described and named after Dr. Bayldon, by Professor Church, in 1865. Found as yet only in Cornwall. BERAUNITE. Named by Breithaupt, in 1841, from Beraun, in Bohemia. BERTHIERITE. Described by Berthier, in 1827, and named Haidingerite ; named by Haidinger, in the same year, after Berthier. BERYL. Described by Theophrastus and other ancient writers; defined by Vauquelin, in 1800. CHAPTER III. DESCRIPTIVE. 31 BISMITE. Separated from Bismuthite by Dana, 1868. BISMUTH. Described by Agricola, 1546. BISMUTHINITE. First described by Cronstedt, 1758 ; named Bismutbine, by Beudant, 1832 ; named Bismuthinite, by Dana, 1868. BITUMEN. Mentioned by Pliny. BLEINIERITE. Named Blei-Niere, by Karsten, 1800, thus signifying Lead- Kidney-ite. Dana proposes to name it after Bindheim, its first analyst. BLENDE. Described by Agricola, in 1546 ; named Bldnde, by Wallerius, in BOURNONITE. First described by Rashleigh, 1797, having been discovered in Cornwall ; named after its discoverer, Comte de Bournon, by Jameson, in 1816. BRAUNITE. First described and named after M. Braun, of Gotha, by Haidinger, in 1826. BROCHANTITE. Named and described by Levy, in 1824, after Brochant de Villiers. Found in Cornwall about the year 1864. BROOKITE. First described by Soret, 1822 ; named by Levy, in 1825, after the British mineralogist, H. J. Brooke. CALAMINE. First described by Agricola, in 1546 ; separated from the Silicate of Zinc, and named Smithsonite, by Beudant, 1832. Calc.edony. Named Chalcedonius, by Agricola, in 1546. CALCITE. Named Kalchstein (Limestone), by Agricola, in 1545 ;* Calcite, by Haidinger, 1845. CASSITERITE. (Gr. Kassiteros, tin.) Named Cassiterit, by Beudant, in 1832. CELESTITE. First described by Schutz, in 1791 ; named from Ccelestis, celestial from a faint shade of blue often present, by "Werner, 1798. CERUSSITE. Named Ceruse, by Beudant, in 1832, from the Cerussa (artificial Carbonate of Lead) of Pliny and Agricola. CERVANTITE. Defined and named, by Dana, in 1854, from Cervantes, in 'Galicia, Spain. CHALYBITE. (Gr. Chalybs, iron.) Named by Glocker, in 1847. CHENEVIXITE. Named by Adam, after the celebrated chemist, Chenevix, who published its first analysis. Found only in Cornwall. CHESSYLITE. Described by Wallerius, in 1747 ; named by Brooke and Miller, in 1852, from its chief locality, Chessy, in France. CHILDRENITE. Named by Levy, in 1823, after the celebrated mineralogist Children. CHLORITE. (Gr. Chloros, green.) Name very ancient. CHLOROPAL. Named by Bernhardi and Brandes, in 1822. CHONDRODITE. (Gr. Chondros, a grain.) First described and named by d'Ohsson, in 1817. CHROMITE. (Chrome-Stone.) First described by Vauquelin, in 1800; named thus by Haidinger, in 1845. CHRYSOCOLLA. (Gr. Chrysos, golden; colle, glue.) Named thus by Agricola, in 1546. CHURCHITE. Named by C. G. Williams, in 1865, after its first analyst, Prof. A. H. Church ; discovered by Mr. Tailing, of Lostwithiel, about 1865, and not yet found out of Cornwall. CLINOCLASE. (Gr. Klino, to incline, and klao, to cleave.) First described by Klaproth, in 1801, in allusion to its inclined cleavages. Named thus by Breithaupt, in 1830. COBALTITE. (Ger. Kobold, a mine-demon.) First described by Cronstedt, in 1758; named Cobaltine, by Beudant, in 1832. CONNELLITE. First described by Rashleigh, in 1802; named by Dana, in 1850, after its first analyst, Connell. Not hitherto found out of Cornwall. COPPER. (Lat. Cuprum.) A corruption of Cyprium, whence it was anciently brought. CORNWALLITE. First described and named by Zippe, in 1845, from its occurrence in Cornwall. Not found elsewhere. COVELLITE. Described by Breithaupt, in 1817 ; named by Beudant, after its discoverer, Covelli, in 1832. CROMFORDITE. Described as Hornblei, by Karsten, in 1800 ; named by Greg and Lettsom, in 1858, from its occurrence at Cromford, in Derbyshire. CRONSTEDTITE. First described and named by Steinmann, in 1821, after the Swedish mineralogist, Cronstedt CUPRITE. (Lat. Cuprum.) Named thus by Haidinger, in 1845. CYANOSITE. (Gr. Kuanos, blue.) Named Cyanose, by Beudant, in 1832. CHAPTER III. DESCEIPTIVE. DEMIDOFFITE. Named after Demidoff, by Nordensk, in 1856. Dana regards it as a variety of Chrysocolla. DIALLOGITE. Named Dialogite, by Jasche, in 1817. DOLOMITE. Named Dolomie by Saussure, in 17%, after the celebrated Dolomieu, who first called attention to some of its peculiar properties, in 1791. DOMEYKITE. First described by Zinken, in 1837 ; named by Haidinger, in 1845, after the celebrated mineralogist, Domeyko. EPIDOTE. Described by de 1'Isle, in 1783, as a variety of Schorl; named Epidote, by Hauy, in 1801. ERINITE. Named by Haidinger, in 1828, from its supposed occurrence in Ireland, but shewn by Professor Church to be a Cornish species. ERUBESCITE. First described by Henckel, in 1725 ; named Erubescite, by Dana, in 1850. ERYTHRITE. (Gr. Eruthros, red.) First described by Briickmann, in 1727; named Erythrine, by Beudant, in 1832. FAHLERZ. (Ger. Fahl, ash-coloured; erz, ore.) First described by "Wallerius, in 1747, and named by him Falerts. felspar. (Ger. Feldspath, rock-spar.) A very ancient name. FLUELLITE. First described and named from the presence of Fluorine, by Levy, in 1824. Not found out of Cornwall. FLUOR. (Lat. Fluere, to flow.) First described and the name applied by Agricola, in 1529, in allusion to its value as a flux. GALENA. (Gr. Galeo, I shine.) First named and described by Agricola, in 1546. GARNET. (Fr. Grenat, a grain.) Described as a variety of Anthrax, by Theophrastus ; named Granat, by Wallerius, in 1747. GILBERTITE. Named and described, by Thomson, Min. I., p. 236. GLAUOONITE. (Gr. Glaucos, bluish -green.) First described and named, by Keferstem, in 1828. GOLD. A very ancient name. GOSLARITE. First described by Agricola, in 1546 ; named by Haidinger, from its first known locality, Goslar, in 1847. GRAPHITE. (Gr. Grapho, I write.) Described by Bromell, in 1739; named Graphite, by "Werner, in 1789. GYPSUM. (Gr. Gypsos, lime.) Described by Herodotus and Theophrastus. (325 B.C.) Named Gypsum, by Agricola, in 1546. HALITE. Named by Glocker, in 1847. HEMATITE. (Gr. Raima, blood.) Described by Theophrastus (325 B.C.), and named Aimatites. HISINGERITE. First described and named by Berzelius, in 1828. HYPERSTHENE. (Gr. Hyper, above, or excess ; sthenos, strength.) First described as Labrador Hornblende, by Werner, in 1789 ; named by Hauy, in 1803. ILMENITE. First described and named Menachanite, by Wm. McGregor, in 1791 ; named Ilmenite, by Kupfer, in 1827 ; re-named Menaccanite, by Dana, in 1868. ISOPYRE. (Gr. Isos, equal, and Pyr, fire.) First described and named by Turner, in 1827. JAMESONITE. First described by Jameson, in 1820; named after him, by Haidinger, in 1823. JASPER. A very ancient name. JOHANNITE. Discovered, by John, in 1821 ; named after him, by Haidinger, in 1830. KALINITE. Known as alum for a very long period ; named by Dana, in 1868. KAOLIN. Described by Werner, in 1780 ; the name is Chinese. KERATE. (Gr. Keras, a horn. ) Described by Gesner, in 1565 ; named by Haidinger, in allusion to its horny nature, in 1845. LANGITE. First described by Maskelyne, and named after Dr. Lang, in 1864. LEPIDOLITE. (Gr. Lepis, a scale.) First described by Yon Born, in 1791 ; named by Klaproth, in 1794. LEPIDOMELANE. (Gr. Lepis, and melas, black.) Described and named by Hausmann, in 1840. LEUCOPYRITE. (Gr. Leucos, white, and pyrites.) First described by Jameson, in 1820 ; named by Shepard, in 1835. LIBETHENITE. Described by Leonhardt, in 1812 ; named by Breithaupt, in allusion to its chief locality, Libethen, in 1823. CHAPTER III DESCEIPTIYK 33 LlMONiTB. Described very anciently. Separated from Hematite and named, by Beudant, in 1832, from Leimon, a meadow; more particularly applicable to Bog Iron Ore. LINARITE. First described, and named from its first locality, Linares, in Spain, by Brooke, in 1822. LIROCONITE. (Gr, Leiros, pale, and konis, dust.) First described by Bournon, in 1801 ; named by Mohs, in allusion to its pale streak, in 1822. LUNNITE. First described by Klaproth, in 180 L ; named by Bernhardi, in 1844. MAGNESITE. Described by Werner, in 1803 ; named by Karsten, in 1808. MAGNETITE. So named, from its magnetic properties, by Haidinger, in 1845. The mineral was known by the ancients. MALACHITE. (Gr. Malakos, soft.) Included with Chrysocolla by Theo- phrastus; named Molochit, by Agricola, in 1546; Malachit, by Wallerius, in 1747. MANGANITE* First described by De Lisle, in 1783 ; named Manganite, by Haidinger, in 1827, in allusion to the manganese contained in it. MARCASITE. This name, which is of Moorish origin, was formerly applied to ordinary crystallized Pyrites. The present species was distinguished, and the name restricted, by Haidinger, in 1845. MELACONITE. (Gr. Melas> black, and konis, powder.) First described by Werner, in 1789 ; named by J. N. Hust, in 1841. MELANTERITE. (Gr, Melas, black.) Known to the ancients by the name Melanteria. Name adopted by Beudant, in 1832. MESOLITE. First described by Fuchs and Gehlen, in 1816. MILLERITE. First described by Werner, in 1789 ; named by Haidinger, in 1845, in honour of Dr. Miller, the eminent crystallographer. MIMETITE. (Gr. Mimetes, imitator.) First described by Wallerius, in 1748 ; named Mimitese, by Beudant, in 1832, on account of the resemblance of its crystals to those of Pyromorphite ; named Mimetit, by Haidinger, in 1844* MISPICKEL. Described by Agrioola, in 1546, as Mist-puckel; Mispickel, by Wallerius, in 1747. Name Arsenopyrite proposed by Dana, in 1868. MOLYBDENITE. Included with Graphite by Wallerius, in 1747; named Molybdaena by the discoverer of its metallic base, Hielm, in 1782; Molybdenite, by Brongniart, in 1807. MUSCOVITE. Named by Dana, in 1850, in allusion to its common occurrence in some parts of Russia (Muscovy). NATROLITE, First described by Cronstedt, in 1758. Named by Klaproth, in 1803, in allusion to the soda (natron) contained in it, NICCOLITE. First described by Hiarne, in 1694; named Nickeline, by Beudant, in 1832, in allusion to its contained metal ; named Niccolite, by Dana, in 1868. OLIVENITE. Discovered in Cornwall ; first described by Klaproth, in 1786 ; named Olivenerz, by Werner, in 1789, in allusion to its olive-green colour ; named Olivenite, by Jameson, in 18 SO 2 Pbo" Celestite . .. SrSO 4 Barytes BaSO 4 Hydrous. Gypsum CaSO 4 + 2H 2 O Cyanosite CuSO 4 + 5H 2 O Melanterite FeSO 4 + 7H 2 O Goslarite ZnSO 4 + 7H 2 O Johannite USO 4 + H 2 O (somewhat uncertain.) Kalinite (JA1JK)SO 4 + 6H 2 O Linarite PbSO 4 + CuH 2 O 2 Langite CuSO 4 + 3CuH 2 O 2 + 2H 2 O Brochantite 2CuSO 4 + 5CuH 2 O 2 ARSENIATES AND PHOSPHATES. Anhydrous* Mimetite 3(Fb 3 As 2 O 4 ) + PbCl 2 Pyromorphite 3(Pb 3 P 2 O 4 ) + PbCl 2 Apatite : a. Chloroapatite 3(Ca 3 P 2 O 4 ) + CaCl 2 b. Fluorapatite . 3(Ca 3 P 2 O 4 ) + CaF 2 Hydrous. Olivenite Cu 3 As 2 O 8 + CuH 2 O 2 Clinoclase Cu 3 As 2 O 8 + 3CuH 2 O 2 Cornwallite a, ... Cu 3 As 2 O 8 + 2CuH 2 O 2 + H 2 O b. ... Cu 3 As 2 O 8 + 2CuH 2 O 2 + 3H 2 O Erinite Cu 3 As 2 O 8 + 2CuH 2 O 2 CLalcophyllite a. Cu 3 As 2 O 8 + 5CuH 2 O 2 + 7H 2 O b. Cu 3 As 2 O 8 + 5CuH 2 O 2 + 9H 2 O c. Cu 3 As 2 O 8 + 5CuH 2 O 2 + A1 2 H 2 O 6 + 16H 2 O d. Cu 3 As 2 O 8 + 5CuHoO 2 + A1 2 H 2 O 6 + 17H 2 O Liroconite 2(Cu 3 As 2 O 8 ) + 2CuH 2 O 2 + A1 2 H 2 O 6 + 19H 2 O Chenevixite Cu 3 As 2 O 8 + Fe 3 As 2 O 8 + CuH 2 O 2 + FeH 2 O 2 + 4H 2 O Bayldonite Cu 2 PbAs 2 O 8 + CutL,O 2 + 2H 2 O Annabergite Ni 3 As 2 O 8 + 8H 2 O Erythrite Co 3 As 2 O 8 + 8H 2 O Pharmacosiderite. Fe 3 As 2 O 8 + 8H 2 O Scorodite Fe 3 As 2 O 8 + 4H 2 O Pitticite Fe 2 As 2 8 + H 2 SO 4 CHAPTER IV. SYSTEMATIC. 41 II. ECONOMICAL. (Adopted at the Museum of Practical Geology, Jermyn-street, London.) DIVISION I. NON-METALLIC MINERALS. CLASS I. CARBON AND BORON. Group 1. Carbon and its Com- Group 3. Inflammable Salts. pounds. Group 4. Boron and its Ccm~ Graphite. pounds. Anthracite. Group 2. Hydrocarbons. Bitumen. Eetinite. CLASS 2. SULPHUR AND SELENIUM. Group 1. Sulphur and its Com- Group 2. Selenium and its Com- pounds, pounds. Sulphur. CLASS 3. HALOIDS AND SALTS. Group 1. Ammonia. Group 6. (Cont.) Group 2. Potash. Scheelite. Group 3. Soda. Fluor. Halite. Group 7. Magnesia. Group 4. Baryta. Magnesite Barytes. Group 8. Alumina* Group 5. Strontia. Kalinite. Celestite. Wavellite Group 6. Lime* Tavistockite Calcite. Childrenite Aragonite. Group 8. Ceria. Dolomite. Churchite Apatite. Group $.Zirconia. Gypsum. Group 16. Yttria. CLASS 4. EARTHS. (Silica, Alumina, and Magnesia, with their hydrates.) Group 1. Silica. Group 2. A lumina. Quartz Group 3. Magnesia. Jasper Calcedony Opal CLASS 5. SILICATES AND ALUMINATES. The groups here are mostly chemical, the Felspars, Zeolites, and Garnets being made into distinct groups. DIVISION II.-METALLIC MINERALS. CLASS 1. MINERALS CONTAINING METALS THAT ARE BRITTLE AND FUSIBLE ONLY WITH DIFFICULTY. Group 1. Titanium. Group 8. Uranium. Anatase Zippaeite Rutile Pitchblende Brookite Johannite Ilmenite Autunite Titanite Torbernite Group 2. Tantalum. Group 9. Manganese. Group 3, Niobium and Pelopium. Psilomelane Group 4. Tungsten. "Wad Wolframite Pyrolusite Scheelite Manganite "Wolfram Braunite Group 5. Molybdenum. Diallogite Molybdenite Rhodonite Group 6. Vanadium. Group 7. Chromium. Chromite 42 CHAPTER IV. SYSTEMATIC. CLASS 2. MINERALS CONTAINING METALS THAT ARE BRITTLE, EASILY FUSIBLE, AND VOLATILE. Group 1. A rsenic. Group 2. f Cont. ) Arsenic Ceryantite Arsenolite Antimonite Leucopyrite Jamesonite Condurrite Group 3. Tellurium. Smaltite Group 4. Bismuth. Group 2. Antimony. Bismuth Antimony Bismite Senarmontite Bismuthinite Valentinite Wittichenite Stibiconite CLASS 3. MINERALS CONTAINING METALS THAT ARE MALLEABLE ; NOT EEDUCIBLE BY HEAT ALONE. Group I. Zinc. Group 6. Cobalt. Calamine Asbolane Blende Cobaltite Goslarite Smaltite Group 2. Cadmium. Erythrite Group 3. Tin. Group 7. Nickel. Cassiterite Annabergite Stannite Millerite Group 4. Lead. Niccolite Plumbic Ochre Pentlandite Cerussite Group 8. Copper. Galena Copper Anglesite Cuprite Cromfordite Melaconite Pyromorphite Malachite Mimetite Chessylite Bleinierite Lunnite Jamesonite Libethenite Bournonite Chalcocite Linarite Covellite Group 5. Iron. Erubescite Magnetite Chalcopyrite Hematite f ahlerz Goethite Tennantite Limonite Bournonite Chalybite Brochantite Vivianite Cyanosite Pyrrhotite Atacamite Pyrites ChrysocpUa Marcasite Torbernite Mispickel Condurrite Leucopyrite Cornwallite Melanterite Clinoclase Cronstedtite Olivenite Chloropal Liroconite Pharmacosiderite Chalcophyllite Scorodite Pitticite CLASS 4. MINERALS CONTAINING NOBLE METALS ; REDUCIBLE BY HEAT ALONE. Group 1. Mercury. Group 3. Gold. Gold >Group 2. Silver. Group 4. Platinum. Silver Group 5. Palladium. Kerate Group 6. Rhodium. Argentine Group 7. Iridium. Stephanite Group 8. Osmium. Polybasite Group 9. Lanthanium. Pyrargyrite Group 10. Columbium. CHAPTER IV. SYSTEMATIC. 43 III. MIXED. (System of Weiss and Nicol.) ORDER I. OXIDISED STONES. Fam. 1. Quartz. Fam. !.( Cont. ) Quartz Pyroxene Jasper Hypersthene Calcedony Khodonite Opal Babingtonite Fam. "2. Felspar* Isopyre Orthoclase Fam. 8. Clay. Albite Kaolin * Fam. 3. Scapolite. Smectite Prehnite Allophane Fam. 4. Haloid Stones, Schrotterite Wavellite Agalmatolite Fam. 5.- Zeolite. Steatite Natrolite Fam. 9. Garnet. Stilbite Garnet Analcite Epidote Fam. 6. Mica. Axinite Muscovite Andalusite Lepidolite Staurolite Lepidomelane Fam. 10. Gems. Chlorite Topaz Talc Beryl Schiller-spar Tourmaline Serpentine Chondrodite Cronstedtite Fam. 11. Metallic Stones. Fam. 7. Hornblende. Chloropal Amphibole ORDER 2. SALINE STONES. Fam. l.Calc Spar. Fam. 3. (Cont.) Calcite Celestite Aragonite Fam. 4. Gypsum. Dolomite Gypsum Magnesite Fam. 5. Rock Salt. Fam. 2. - Fluor Spar. Halite Fluor Kalinite Fluellite Melanterite Apatite Goslarite Childrenite Cyanosite Fam. 3. Heavy Spar. Johannite Barytes ORDER 3. SALINE ORES. Fam. 1. Sparry Iron Ores. Fam. 2. (Cont.) Chalybite Brochantite Diallogite Langite Calamine Vivianite Pitticite Torbernite Fam. 2. Copper Salts. Autunite Chrysocolla Erythrite Chessylite Annabergite Malachite Fam. 3. Lead Salts, Chalcophyllite Cerussite Erinite Anglesite Liroconite Linarite Olivenite Cromfordite Clinoclase Pyromprphite Lunnite Mimetite Libethenite Bleinierite Atacamite Kerate Pharmacosiderite Scheelite Scorodite 44 CHAPTER IV. SYSTEMATIC. ORDER 4. OXIDISED ORES. Fam. 1. Oxidised Iron Ores. Magnetite Chromite Ilmenite Hematite Limonite Goethite Fam. 2. Tin Ore. Cassiterite Wolfram Titanite Brookite Anatase Kutile Pitchblende Fam. 3. Manganese Ores. Pyrolusite ORDER 5.- Fam. S.-(Cont.) Manganite Braunite Psilomelane Wad Asbolane Bismite Wolframite Zippaeite Plumbic Ochre Fam. 4. Red Copper Ores. Cuprite Fam. 5. While Antimony Ores. Valentin ite Senarmontite Arsenolite NATIVE METALS. Fam. 1. Fam. \.(Cont.) Gold , Bismuth Silver Antimony Copper Arsenic ORDER 6. SULPHURETTED METALS. Fam. I. Pyrites. Pyrites Marcasite Pyrrhotite Leucopyrite Mispickel Cobaltite Smaltite Niccolite Millerite Pentlandite Chalcopyrite Erubescite Condurrite Fam. 2. Lead Glance, Galena Argentite Chalcocite Covellite Molybdenite Fam. 1. Sulphur. Sulphur Fam. 2. Diamond, Fam. 3. Coals. Graphite Anthracite Fam. 3. Grey Antimony Ore. Antimonite Jamesonite Berthierite Bismuthinite Fam, 4. Grey Copper Ore. Fahlerz Tennantite Bournonite Stephanite Polybasite Stannite Wittichenite Fam. 5. Blende. Blende Fam. Q.Ruby Blende. Pyrargyrite ORDER 7. INFLAMMABLE. Fam. 3.(Cont.) Lignite Fam. 4. Mineral Resins. Bitumen Retinite IV. ARRANGEMENT ACCORDING TO CRYSTALLINE FORM. Analcite Argentite Arsenolite Bismite (?) Blende Chromite Cobaltit* Copper Cuprite Erubescite Fahlerz Fluor Galena Garnet 1. CUBIC. Gold Halite Kalinite Kerate Magnetite Pentlandite Pyrites Senarmontite Silver Smaltite Stannite (?) Tennantite Pharmacosiderite Wolframite (?) CHAPTER IV. SYSTEMATIC. 45 2. PYRAMIDAL. Anatase Chalcopyrite Scapolite Rutile Braunite Cromfordite Scheelite Torbernite Cassiterite 3. RHOMBIC. Andalusite Anglesite Cerussite Lepidomelane Cervantite Libethenite Pyrolusite Scorodite Antimonite Chalcocite Liroconite (?) Stephanite Aragonite Childrenite Lunnite (?) Staurolite Atacamite Chondrodite Manganite Stilbite Autunite Erinite (?) Marcasite Sulphur Barytes Berth ierite Fluellite Mispickel Gilbertite Natrolite Tavistockite (?) Topaz Bismuthinite Goethite Olivenite Valentinite Bournonite Goslarite Pinite Wavellite Brochantite Jamesonite Polybasite (?) Wittichenite Brookite Langite Porcellanite (?) Wolfram Celestite Lepidolite Prehnite 4. OBLIQUE. Amphibole Clinoclase Johannite Pyroxene Annabergite Epidote Linarite Rhodonite Beraunite Erythrite Malachite Schiller Spar Chessylite Gypsum Melanterite Titanite Churchite Hypersthene Orfchoclase Vivianite 5. ANORTHIC. Albite Axrnite Babingtonite Mesolite? Cyanosite Saussurite ? 6. HEXAGONAL. Antimony Chalybite Hematite Niccolite Apatite Chlorite Ilmenite Pyrargyrite Arsenic Beryl Connellite Magnesite Covellite Millerite Pyromorphite Pyrrhotite Bismuth Cronstedtite Mimetite Quartz Calamine Diallogite Molybdenite Talc Calcite Dolomite Muscovite (?) Tourmaline Chalcophyllite Graphite 7. -AMORPHOUS. Agalmatolite Chloropal Kaolin Retinite Agnesite Chrysocolla Limonite Schrotterite Allophane Cornwallite Melaconite Serpentine Asbolane Demidoffite Opal Smectite Bayldonite Domeykite Pigotite Steatite Bitumen Glauconite Pitchblende Stibiconite Bleinierite Hisingerite Pitticite Wad Calcedony Isopyre Plumbic Ochre Zippseite Chenevixite Jasper Psilomelane CHAPTER V. DISTRIBUTIVE. Of the large number of minerals which have been found in the district treated of in this Handbook, some, as the various forms of Quartz, occur almost everywhere ; others, such as Pyrites, are found wherever mining is carried on ; others, again, occur only in small quantities or are limited to certain areas. Thus, ores of Iron, chiefly Hematite or Limonite, are to be found in the parish and neighbourhood of St. Just, in the parishes of Constantine, Ladock, 46 CHAPTER V.DISTBIBUTIVE. and Perranzabuloe, at Huel Ruby, Retire, and Restormel ; at Ilsington, Brixham, and other places, while small quantities of the same, and closely related minerals, are to be met with in most mines. Manganese ores are by no means so widely distributed, for they are almost entirely unknown in the West of Cornwall, although found in abundance near Launceston, near Tavistock, Brent Tor. at Upton Pyne, and many other places ill Devonshire. Among the rarer " metallic minerals " several of the arseniates of copper have only been noticed in Gwennap. Ilmenite or Titaniferous Iron Ore is only to be found in or near St. Keverne ; Anatase and Brookite occur in very small quantities only at Virtuous Lady Mine, near Tavistock, Delabole, Tintagel, and in a quarry near St. Austell. The distinguishing material of these minerals, however, Titanic Acid, is very widely distributed through our Cornish rocks, as shewn by Mr. J. A. Phillips's recent analyses, so that additional localities for them may perhaps occur ere long. Chromite has been found in small quantity, but only in the Lizard district. Among the "non-metallic" minerals, Garnet only occurs near a junction of granite and greenstone, the localities being tolerably numerous, although the mineral is never abundant. Topaz occurs only in granite, but in localities as widely separated as St. Michael's Mount and Lundy Island. Beryl has been found in some of the same localities, but is still more rare. Barytes has occurred only at one locality west of Truro, viz., at the Gwennap Mines, with copper ores. It has also occurred in tolerable quantity at Herodsfoot, at Huel Mary Ann, with lead ores, and at Babbicombe Bay, and other localities in Devon, with Calcite. The Zeolites are found only at St. Just, in a narrow strip of greenstone, which forms the precipitous coast, and at Stenna Gwynn, and very sparingly even in these localities. Wavellite has only been certainly found near Barn- staple, although found there 87 years ago. Graphite has occurred in small nodules in elvan courses at Kerjiliack, near Penryn ; at Tuckingmill ; near Grampound ; and at Bpscastle. Retinite has occurred only in the Lignites of Bovey Tracey ; Mineral Pitch only in the copper mines in Gwennap, Illogan, and neighbouring parishes, and perhaps at Chudleigh, in Devon. A list of mines and mineralogical localities in the two counties, with the minerals which have been noticed, is given below. The more common minerals are only mentioned when particularly fine, or remarkable for their situation. Of the rarer minerals every locality known to the author has been set down. Mines at work in January, 1871, are indicated by small capitals, and the material chiefly raised is indicated in a separate column. "When a mineral is very characteristic of a given locality, or occurs in a very fine condition, its name is printed in small capitals. LIST OF MINES AND MINERALOGICAL LOCALITIES, TOPOGRAPHICALLY ARRANGED. CORNWALL. HUNDRED OF PEN WITH. (West Division.} Parish. Locality. Pr Mme8 f ! More remarkable Minerals. Scilly. Sennen. Do. St. Levan. Land's End. Nangisel Cov.e. Tol Pedn Pen- with. Flints on the beaches and high lands (DelaBeche, Rep. Dev. Corn.) Schorl occasionally in the granite, sometimes replacing Mica (Statham, Geologist, voL II., p. 23. Schorl, fractured flints in elevated positions. Amethyst, Pinite ; occasionally fine crystals of Orthoclase in the Granite. Pinite. CHAPTER V. DISTRIBUTIVE. 47 LIST OP MINES, &c. CORNWALL, PENWITH, West Division (Cont.) Parish. Locality. Produce of Mines. More remarkable Minerals St. Burian. Boscawen Cliffs. _ Axinite, Rock Crystal. Do. Penberth. WOOD-TIN. Do. Lamorna Cove. Axinite, Epidote, Pinite, Topaz. Do. Rose-moddress. Garnet. Do. Cam Silver. Epidote. St. Just. BALLESWIDDEN Tin. Bismuthinite, Bismuth, Litho- marge; fine crystals of Ortho- clase, and Mica in the Granite. Do. Bellon, Huel. Amethyst, Mica. Do. BOSCASWELL or Tin and Calcedony, Cassiterite. BOSCASWELL Copper. DOWNS. Do. BOSCEAN. Tin. Fine imbedded crystals of red- Boscreagen. dish-brown and white Ortho- clase. Do. BOSOKN. Tin. Occasionally fine crystals of Cas- siterite. Do. Boshase Moor. Stream Tin. Do. BOSWEDDAN and Tin. Beryl (Huel Castle). HUEL CASTLE. Do. BOTALLACK and Tin and Actinolite, Amethyst, Apatite, CARN YOUTH, Copper. Aragonite, Atacamite, Augite, with HUEL COCK Axinite, Bismuth, Bismuthinite and the Cliffs to BOTALLACKITE, Calcite, Chal- the north. cocite, Cobaltite, Cyanosite, Di- allogite, Dolomite, Epidote, Ery- thrite, Fahlerz? Fluor, Garnet, Goethite, Goslarite, Jasper, Ke- rate, Magnetite, Malachite, Man- ganite, Mesolite, Mispickel, Na- trolite, Opal, Pitchblende, Phar- macosiderite, Prehnite, Pyrrho- tite, Silver, Smaltite, (Steatite, Stannite, Stilbite, Tallingite, Tourmaline, Tremolite, Vivian- ite, &c. Do. Cape Cornwall. Schorl, Hornblende, Actinolite. Do. CAPE CORNWALL Tin. Dolomite, Garnet, Jasper. MINE. Do. Carne, Huel. Axinite, ISOPYRE, Prehnite, Na- trolite, Stilbite. Do. Carn Bosavern. LEPIDOMELANE. Do. Do. Chycornish Carn. Crowns Rock. Garnet. GARNET, MAGNETITE, Actinolite, APATITE, AXINITE, Epidote, Na- trolite, Prehnite, &c. Do. Cunning, Huel. Mica, Cassiterite. Do. Diamond, Huel. ROCK CRYSTAL. Do. LEVANT. Tin and Amethyst, Aragonite, Bismuth, Copper. Bismite, Chalcocite, Dolomite, Fahlerz? Hornblende, Kerate, Pharmacosiderite, SILVER. Do. LEVANT, NORTH. Tin. Cassiterite. Do. Little Bounds. Chlorite, Schorl. 48 CHAPTER V. DISTRIBUTIVE. LIST OF MINES, &c. CORNWALL, PENWITH, West Division (Cont. ) Parish. Locality. Produce of Mines. More remarkable Minerals. St. Just (CW.) OWLES, HUEL & Tin. Actinolite, Apatite, Calcite, Cha- Huel Edward. lybite, Diallogite, Pharmacosi- derite (Huel Owles); Aragonite, Autunite, Chrysocolla, Mala- chite, Pitchblende, Torbernite, VIVIANITE, Zippaeite (Huel Ed- ward). Do. Pendeen Consols Tin and Cassiterite. Copper. Do. Pendeen Cove Steatite, in small veins in slate. (south of). Do. Parknoweth. Cassiterite, Chlorite, Schorl, Vi- vianite. Do. Roscommon Cliff Asbolane, Axinite, Erythrite, Se- lenite, Tourmaline. Do. SPEARNE CON- Tin. SOLS. Do. SPEARN MOOR. Tin and Fluor, Rock Crystal. Copper. Do. Stennack, Huel. Jasper. Do. St. JUST AMAL- Tin. Cassiterite. GAMATED. Do. Tregarva Moor. Cassiterite, Gold (in ancient stream works). Do. Trewellard Cliff. Axinite, Pinite, Rock Crystal. Sancreed. Mulvra Hill. Pinite ; fine crystals of Orthoclase Paul. Wherry Mine. Tin. Cassiterite, Cobaltite. Morvah. Garden Mine. Tin. Do. Morvah United. Chlorite, Felspar, Fluor, Hema- tite, Mica, Schorl. Madron. Chalybite, Sphserosiderite. Gulval. DING DONG. Tin. Chlorite, Fluor, Jasper, Chalco- cite, Schorl. Ludgvan. Vorlas. Flint. Do. Darlington, Huel Mispickel, Pyrites, Schorl, Cas- siterite. Do. Darlington, West Huel. Argentite, Galena (argentiferous), NATIVE SILVER. Zennor. CARNELLOW. Copper and Tin. Occasional fine crystals of Cassi- terite. Towednack. GIEW CONSOLS. Tin. Cassiterite, Schorl. Do. Union, Huel. Cassiterite, Chlorite, Mica, Schorl. CORNWALL, PENWITH, East Division. Parish. Localities. Produce of Mines. More remarkable Minerals. Lelant. Do. Do. Do. Consolidated Ms. KITTY, HUEL. MARGARET, HUEL MARGARET, WEST HUEL. Tin. Tin. Tin. Cassiterite, Felspar, Mica, Schorl. Cassiterite, Mica. Cassiterite. Cassiterite. CHAPTER V. DISTRIBUTIVE. 49 LIST OF MINES, &c. CORNWALL, PENWITH, East Division (Cont.) Parish. Locality. Produce of Mines. More remarkable Minerals. Lelant ( Cont. ) MARY, HUEL. Tin. Blende, Calamine, Chlorite, Mis- pickel, Molybdenite. Do. Poldice, West. Actinolite, Cassiterite, Horn- blende. Do. PROVIDENCE, Tin. EAST. Do. PROVIDENCE Tin and Calcedony, Cassiterite, CHALCO- MINES. Copper. CITE, Chalcotrichite, Chlorite, Clinoclase, Copper, Connellite, Liroconite, Mispickel, Pitch- blende, Pyrites, SCHORL, Tor- bernite. Do. Ditto (Including Cassiterite, Chalcocite, Chessy- Huel Speed.) lite, Cuprite, Felspar, Mala- chite, Melaconite, Pyrites, Schorl. (Huel Speed.} Do. PROVIDENCE, Tin. SOUTH Do. Reeth, Huel. Cassiterite, Chalcocite, Chlorite, Felspar, Mica, Schorl. Do. TREVARRACK UTD Tin. Cassiterite, Schorl. St. Ives. Balnoon. Cassiterite, Felspar, Mica, Schorl. Do. FANNY ADELA Tin. Cassiterite. (Hawke's Point). Do. Mellanoweth. Anglesite. Do. PENCROM, HUEL. Tin. Cassiterite. Do, EOSEWALL HILL Tin. Cassiterite. and RANSOM UNITED. Do. ST. IVES CONSO- Tin and Actinolite, BISMUTH, Cassiterite, LIDATED. Copper. CHALCOClTE(very fine,recently), Chalcopyrite, Chalcotrichite, Chlorite, Cyanosite, Felspar, Fluor, Hematite, Isopyre ? Limonite, Mica, Schorl. Do. ST. IVES, WEST. Tin. Cassiterite. Do. TRELYON CONSLS. Tin and Cassiterite. (Huel Venture.) Copper. Do. Trenwith, Huel. Chalcocite, Cuprite, Erythrite, Hematite, Hornblende, Mela- conite, Pitchblende, Torbernite. Do. St. Michael's Mt. Apatite, Beryl, Cassiterite, Fluor, Garnet, Orthoclase, Lepidolite, Pinite, Rock Crystal, Stannite, TOPAZ, Tourmaline, Wolfram, Zippseite. St. Hilary. GREAT WESTERN Tin and Cassiterite. MINES. Copper. Do. Prosper, Huel MFLANTERITE. Do. Marazion Mines. Blende, Chalcopyrite, Felspar, Hornblende, Limonite, Melaco- nite, Pyrites, Tourmaline. Do. Cuddan Point. ACTINOLITE. Perranuthnoe. The Grebe. Actinolite. Do. Mount Mine? Argentite. St. Erth. Bell, Huel. Anglesite, Pyromorphite. 50 CHAPTER V. DISTEIBUTIYE. LIST OF MINES, &c. CORNWALL, PENWITH, East Division (Cont.) Parish. Locality. Produce of Mines. More remarkable Minerals. St.Erth(CW.) Elizabeth, Huel. Blende, Chalcopyrite, Chlorite, Galena, Melaconite, Pyrites. Do. Gilbert, Huel. Cassiterite. Do. Godolphin, West. Actinolite, Blende, Chalcocite, Galena, Malachite, Melaconite. Do. TEEVEN. Tin. Do. MELLANEAB. Copper. Chalcopyrite. Phillack. Alfred, Huel. Bayldonite? Calcite, Cerussite, Calcedony, Chalcocite, Chalco- pyrite, Erubescite, Kerate, Ma- lachite, Mimetite, PYBOMOE- PHITE (the finest ever found in Cornwall), Rock Crystal, Silver. Do. Ann, Huel? Argentite, Kerate. Do. Kayle, Huel. Chlorite, Chalcopyrite, Galena, Melaconite. Do. Boiling Well. Galena. Gwithian. Silver Valley. Kerate, Silver. Gwinear. Carsize Consols. Blende, Cassiterite, Chalcopyrite, Mispickel. Do. Duffield Mine. Chalcocite, Chalcopyrite, Limo- nite, Melaconite, Pyrites. Do. Gwinear, Huel. Cassiterite, Molybdenite. Do. Herland, Huel. AEGENTITE, Bismite, Bismuth, Bismuthinite, Cassiterite, Chal- copyrite, KEEATE, Limonite, Melaconite, Mispickel, Pyrargy- rite, Rock Crystal, Silver, Smal- tite, Wolfram. Do. Providence, Huel. Cassiterite, Chalcocite, Chalco- pyrite, Melaconite. Do. Prince Geo. Mine. Chrysocolla, Malachite. Do. Relistian. Cassiterite, Chalcocite, Chalco- Do. Kelistian, East. pyrite, Melaconite, Pyrites. Chlorite, Tennantite. Do. Rosewarne. Tin & Cop. Cassiterite, Chalcopyrite, Opal. Do. ROSEWAENE, CNLS Tin & Cop. Cassiterite. Do. ROSEWAENE, EST. Tin & Cop. Cassiterite. Do. Rosewarne, New. Cassiterite, Chlorite, Dolomite, Jasper, Semi-Opal. Do. ROSEWAENE UTD. Copper. Chalcopyrite. Do. Tremayne, Huel. Cassiterite, Silver. Do. Trevascus, Huel. Actinolite, Axinite, Bitumen, Blende, Calcedony, Chalybite, Dolomite, Fahlerz, Fluor, Galena, Mispickel, Tennantite. Do. Unity, Huel. Copper and Tin. Actinelite, Amethyst, Asbolane, Bitumen, Blende, Cassiterite, Chalcopyrite, Chalcophyllite, Chessylite, Chlorite, Chryso- colla, Clinoclase, Connellite, Copper, Cuprite, Erythrite, Fluor, Galena, Jasper, Liroco- nite, Malachite, Marcasite, Mi- metite, Mispickel, Molybdenite, Olivenite, Petroleum, Pharma- cosiderite, Pyrites, Scorodite, Tennantite, Torbernite. CHAPTER V.- DISTRIBUTIVE. 51 LIST OF MINES, &c. CORNWALL, PENWITH, East Division (Cont. ) Parish. Locality. Produce of Mines. More remarkable Minerals. Crowan. CKENVER and Tin and Cassiterite, Chalcocite, Chalco- HUEL ABRAHAM Copper. pyrite. Do. MILLET, HUEL. Copper. Chalcopyrite. Do. Strawberry, Huel Blende, Chalcopyrite, Melaco- nite, Pyrites. Camborne. CAMBORNE VEAN Tin and Axinite, Chalcocite, Erubescite, Copper. Fluor, Hornblende. Do. CARN CAMBORNE. Mispickel. Do. CONDURROW, Tin and Cassiterite. SOUTH. Copper. Do. Crofty, Huel. Blende, Galena, Hornblende. Do. DOLCOATH. Tin and Amethyst, Argentite, Arsenic ? Copper. BISMUTH, Bismuthinite,Blende, CASSITERITE, Chalybite, Chalco- cite, Chalcopyrite, Chlorite, Copper, Cobaltite, Cuprite, Dolomite, Erubescite, Eryth- rite, Fluor, Galena, Hematite, Hornblende, Kerate, Langite, Limonite, LITHOMARGE, Mala- chite, Melaconite, Mispickel, Orthoelase, Pitticite, Pitch- blende, Pyrargyrite, Pyrites, ROCK CRYSTAL, Schorl, Silver, Smaltite, Tennantite, Wolfram. Do. Dolcoath, North. Kerate, Silver. Do. GRENVILLE, EAST Copper. Chalcopyrite. Do. GREN VILLE, HUEL Copper. Chalcopyrite. Do. PENDARVESUTD. Tin. Condurrite, Copper, Cassiterite, Fahlerz. Do. ROSKEAR, NRTH. Tin and Actinolite, Blende, Chalcopyrite, Copper. Chlorite, Dolomite, Galena, Haytorite, Jasper, Opal, Prase, Rock Crystal. Do. SETON, HUEL. Copper. Chalcopyrite. Do. STRAY PARK. Copper Cassiterite. and Tin. Illogan. AGAR, HUEL. Copper. Chalcopyrite. Do. BASSET, HUEL. Copper. Argentite, Autunite, Chalcocite, Chalcopyrite, Copper, Cuprite, Galena, Malachite, Silver. Do. BASSET, WEST. Copper and Tin. Chalcopyrite, Cuprite. Do. Basset, South. Argentite, Autunite, Chessylite, Chalcocite, Copper, Fahlerz, Malachite, Rock Crystal, Jo- hannite ? Do. CARN BREA. Copper and Tin. Agate, Cassiterite, Chalybite, Chalcocite, Chlorite, Coudur- rite, Copper, Covellite, Cuprite, Erubescite, Fluor, Goethite, Hematite, Limonite, Mica, Marcasite, Mispickel, Pharma- cosiderite, Pyrites, Rock Crys- tal, Stannite, Tennantite, Wol- fram, Smectite? 52 CHAPTER V. DISTRIBUTIVE. LIST OF MINES, &c. CORNWALL, PENWITH, East Division (Cont.) Parish. Locality. Produce of Mines. More remarkable Minerals. Illogan (Gont.) CAEN BBEA, STH. Tin and Chalcopyrite, Cassiterite. Copper. , Do. COOK'S KITCHEN. Tin and Bitumen, Chalcocite, Chlorite, Copper. Erubescite, Fahlerz, LITHO- MARGE, LONCHIDITE, Marcasite, Mispickel, Pyrites, Schorl, Stea- tite? Tennantite. Do. CROFTY, NORTH Copper Chalcopyrite. HUEL. and Tin. Do. Crofty,EastHuel Actinolite, Axinite, Bitumen, Blende, Rock Crystal. Do. CROFTY, SOUTH Tin and Chalybite, Stannite. HUEL. Copper. Do. DOLCOATH (STH.) Copper. Chalcopyrite. & CARNARTHEN CONSOLS. Do. Druid, Huel. Chondrodite? Condurrite, Goe- thite, Lithomarge, Limonite. Do. EMILY HENRIET- Copper. Chalcopyrite. TA, HUEL. Do. FRANCES, SOUTH Copper. Chalcopyrite, Chalcotrichite, HUEL. Cuprite, Cyanosite, Libethe- nite, Lithomarge. Do. FRANCES, WEST Copper. Chalcopyrite, Cuprite. HUEL. Do. Garth Mine. Cassiterite, WOOD TIN. Do. POOL, EAST. Copper, Tin, & Wolfram. Amethyst, Blende, CALCEDONY, CHALCOPYRITE, Chalcocite, Cha- lybite, CHLOROPHANE, Copper, Cuprite, Erythrite, Felspar, Ga- lena, Leu copy rite, Langite, Ma- lachite, Silver ? Smaltite, ROCK CRYSTAL, WOLFRAM. Do. Pool, North. Copper. Calcedony, Chalcopyrite. Do. SETON, EAST Copper. Chalcopyrite, Pyrites. HUEL. Do. TINCROFT. Tin and Cassiterite, Chalcocite, Chalco- Copper. pyrite, Chalybite, Chlorite, Cu- prite, Erubescite, Goethite, He- matite, Limonite, Lithomarge, Melaconite, Mispiekel, Oliven- ite, Pitchblende, Pyrites, Ten- nantite, Torbernite. Redruth. BASSET, EAST Copper. Chalcopyrite. HUEL. Do. Beauchamp,Huel Chalybite, Goethite, Chalcocite. Do. BULLER, HUEL. Copper Amethyst, Calcite, Cassiterite, and Tin. Chalcocite, Chalcopyrite, Cha- lybite, Chessylite, Copper, CU- PRITE, Fluor, Malachite, Melaco- nite, Olivenite, Opal, Pitch- blende, Rock Crystal, Torber- nite, Zippseite. Do. Cardrew Downs. Chlorite, Fluor, Limonite, Mela- conite. Do. CARNBREA,EAST Copper. Chalcopyrite. CHAPTER V. DISTEIBUTIVE. 53 LIST OF MINES, &c. COKNWALL, PENWITH, East Division (Cont.) Parish. Locality. Produce of Mines. More remarkable Minerals. Redruih(Cont) Do. Clyjah Mine. COPPEK HILL. Copper. Epidote, Garnet, Zippseite. Chalcocite, Chalcopy rite, LANGITE Do. Cupid, Huel. Fluor. Do. Downs, Great Copper. Chalcopyrite. North. Do. Downs, North. Copper. Blende, Cassiterite, Chalcopy- rite, Fluor, Limonite, Mime- tite? Pyrites. Do. Elizabeth, Huel. Smaltite. Do. Fanny, Huel. Chalcocite, Wolfram. Do. HARMONY AND Magnetite, Wolfram. MONTAGUE. Do. PEDN-AN-DEEA. Tin and Copper. AMETHYST, CALCEDONY, Cas- siterite, Chlorophane, Chlorite, Clinoclase, Fluor, Galena, Oli- venite, PHARMACOSIDERITE, Psilomelane ? Pitchblende, Scorodite, Smaltite, Wad ? Wolfram, Zippseite. Do. Scorrier Consols. Kock Crystal, Stannite. Do. SPARNON, HUEL. Tin and Agate, Arsenolite, Bismuth, Copper. Bismuthinite, Cobaltite, Ery- thrite, Fluor, Gold, Millerite, Eock Crystal, SMALTITE. Do. Do. TOLGUS, WEST. TOLGUS, GREAT Copper. Copper. Chalcopyrite. Chalybite, Erubescite, Mispickel, SOUTH. Wad. Do. TOWAN, SOUTH. Copper. BITUMEN, Chalcopyrite. Do. Trefusis, Huel. Chessylite, Chrysocolla, Mala- chite, Melaconite. Do. Treleigh, Consls. Copper. Chalcopyrite. Do. TRELEIGH, NEW. Copper. Do. Treskerby, Nrth. Copper and Tin. Bitumen, Chalcopyrite, Copper, Cuprite, Petroleum? Do. UNY, HUEL. Tin and Blende, Cassiterite. Copper. CORNWALL, KIRRIER, West Division. Parish. Locality. Produce of Mines. More remarkable Minerals. Landewed- nack. Kynance Cove. Agate, Asbestos, Calcite, Dial- lage, Hornblende, Orthoclase, Saussurite? Serpentine, STEA- TITE, Talc. Do. Lizard Head. Calcite, Hornblende, Orthoclase, Talc, Magnetite. Kuan Major. Everywhere. SERPENTINE. Ruan Minor. Cadgwith. Actinolite, Asbestos, Calcite, Chromite, DIALLAGE, Horn- blende, SERPENTINE, PYRITES. Do. Caerleon Cove. Orthoclase, in granite veins. Do. Kildown. Schiller Spar. Do. Kennack Cove. Schiller Spar. 54 CHAPTER V. DI8TEIBUTIYE. LIST OF MINES, &c. CORNWALL, KIRRIER, West Division (Cont.) Parish. Locality. Produce of Mines. More remarkable Minerals. Grade. Goonhilly Downs Asbestos, Calcedony, Hornblende Serpentine. Do. The Balk. Orthoclase and Mica in granite veins. Mullion. Gue Graze. STEATITE. Do. Ghost Croft. Copper. Do. Mullion Island. SERPENTINE. Do. Polurian Cove. Chrysocolla, Copper, Cuprite, Hornblende, Malachite, Pyrites, Do. Pradanack. Serpentine, Steatite. Hornblende. Do. Do. Unity, Huel. Vellan Head. Chrysocolla, Copper, Cuprite. Orthoclase, &c., in granite veins. St. Keverne. Black Head. Diallage, Serpentine, Steatite. Do. Coverack Cove. DIALLAGE, Hornblende, Ortho- clase, SERPENTINE, Steatite. Do. Crousa Downs. Diallage, in Diallage rock. Do. Downas, Huel. Chalcocite, Copper. Do. Gwendra. Menaccanite, disseminated. Do. Gwinter. Magnetite, disseminated in Dial- lage rock ; Saussurite? Do. Karak-clews. DIALLAGE. Do. Lanarth. Manaccanite. Do. Manacle Point. Serpentine, Steatite. Do. Pednboar Point. Hornblende. Do. Polkerris Point. Hornblende, Serpentine. Do.. Porthalla. Hornblende, ILMENITE, Limonite. Do. Treglossack. Calcite. Manaccan. In the bed of a MANACCANITE. stream. Mawgan. Trelowarren. Serpentine, Steatite. Do. Breage. Anson, Huel. FORTUNE, GREAT Copper. Tin and Chalcopyrite, Pyrites. Cassiterite, Chalcocite, Chalco- HUEL. Copper. pyrite, Erubescite, Melaconite, Mica, Orthoclase, Pyrites, Wol- fram. Do. FORTUNE, SOUTH, Copper. Chalcopyrite, Cassiterite. HUEL. Do. Do. Godolphin Bridge GREAT WORK, Copper. Tin and Cassiterite, Chlorite, Dolomite. WEST. Copper. Do. LEEDS MINE. Tin. Cassiterite. Do. NEW HENDRA. Tin. Cassiterite. Do. Pengelly Croft Tin. Cassiterite, Scheelite. Mine. Do. PENHALE, HUEL Tin. Cassiterite, Galena-, Pyrites. VOR. Do. Prosper, Huel. Copper and Tin. Chalcotrichite, Cuprite, Fahlerz, Mimetite. Do. TREMENHEERE. Tin. Do. Tremearne. Albite, Apatite, Fluor, ORTHO- CLASE, Mica, Schorl, Topaz. Do. Trescow. Cassiterite, Copper, Chalcopy- rite. Do. TREWAVAS CLIFF Copper. Chalcopyrite, Chalybite, Fluor. Do. MINE. Do. Trewavas Head. Albite, Schorl, Mica. CHAPTER V. DISTRIBUTIVE. 55 LIST or MINES, &c. CORNWALL, KIBRIEE, West Division (Cont.) Parish. Locality. Produce of Mines. More remarkable Minerals. Breage (Cont.) Tregoning Hill. _ KAOLIN, FINITE. Do. Tresowes. Stream Tin, Jasper, KAOLIN. Do. VOK, GRT. HUEL. Tin and Albite, Apatite? Blende, Cassi- Copper. terite, Chlorite, Chalcopyrite, Copper, Dolomite, Melaconite, Mica, Mispickel, Orthoclase, Pyrites, Steatite, Talc ? Wol- fram ? Gertnoe. GREAT WORK Tin and Blende, CASSITERITE, Chlorite, CONSOLS. Copper. Chalcopyrite, Cuprite, Fahlerz, Limonite, Melaconite, Mica, Pyrites, Tourmaline. Do. LEEDS and ST. Tin. Cassiterite. AUBYN. Do. Christopher, Huel Tin. Cassiterite, Mica, Orthoclase. Do. Fortune, South Tin. Cassiterite. Huel. Sithney. Prospidnick,Huel Lead. Chlorite, Pyrites, Wolfram. Do. Penrose, Huel. Anglesite, Calcite, Cerussite, Chalcopyrite, Chalybite, Ga- lena, Limonite, Linaiite, Mime- tite, Pyrites, PYROMORPHITE, Plumbic Ochre. Do. Rose, Huel. Lead. Anglesite, Cerussite, Chalybite, Galena, Limonite, Pyromor- phite, Quartz. Do. Sithney, Carn- Tin. Cassiterites, Pyrites. meal. Do. Susan, Huel. Tin and Chalcopyrite, Copper, Cassiterite, Copper. Mica. Do. Trannack, Huel. Copper. Cassiterite, Chalcocite, Chryso- Do. Unity, Huel. colla, Chalcopyrite, GARNET, Mica, Pyrites, Schorl. Cerussite, Chalcopyrite, Galena, Pyrites. Do. Vor, East Huel. Tin. Cassiterite, Chalcopyrite, Mala- chite. Wendron. Ann, Huel. Tin. Argentite, Cassiterite, Cerussite, Felspar, Limonite, Mica, Silver. Do. BALMYNHEAK. Tin. Cassiterite. Do. BASSET and Tin. GRYLLS. Do. Hallebezac. Cassiterite, Kaolin. Do. LOVELL CONSOLS. Tin. Do. LOVELL, EAST Tin. CASSITERITE. HUEL. Do. LOVELL, NEW Tin. Cassiterite. HUEL. Do. LOVELL, NORTH. Tin. Cassiterite. Do. TREVENNEN, NEW Tin. Cassiterite. Do. TREWORLIS. Tin and Cassiterite, Chalcocite, Chalcopy- Copper. rite, Magnetite, Mispickel, Pyrites. Do. TRUMPET CON- Tin. Cassiterite, Felspar, Limonite, SOLS. Mica. Do. TRUMPET, EAST. Tin. Cassiterite. 56 CHAPTER V. DISTEIBUTIVE. LIST OF MINES, &c. CORNWALL, KIRRIER, East Division, Parish. Locality. Produce of Mines. More remarkable Minerals. Gwennap. Ale and Cakes. Copper. CHALCOPYRITE. Do. Barrier Mine. Stannite. Do. CLIFFORD, NEW. Tin and Cassiterite. Copper. Do. Consolidated Ms. Copper. BARYTES, Cassiterite, Chalcocite, . Chalcopyrite, Copper, Cuprite, Gypsum, Melaconite, Molybde- nite, Orthoclase, Pyrites, Kock Crystal, Schorl. Do. Damsel, East Copper. Chlorite, Chalcocite, Chalcopy- Huel. rite, Copper, Fluor, Kaolin, Lithomarge, Melaconite, Phar- macosiderite, Pyrites. Do. DAMSEL, WEST Tin. Cassiterite, Fluor. HUEL. Do. Fortune, Huel. Copper. Chlorite, Chalcopyrite, Felspar, Limonite, Pyrites, Schorl. Do. Friendship, Huel Albite, Blende, Molybdenite, Wolframite. Do. Gorland, Huel. Copper. Asbolane, Chalcophyllite, Chal- copyrite, Chalcotrichite, Ches- sylite, Chrysocolla, CLINOCLASE, Copper, Cuprite, Fluor, LIRO- CONITE, Malachite, Mimetite, Molybdenite, OLIVENITE, Opal, PHARMACOSIDERITE, SCORODITE Torbernite, Vivianite. Do. Jewel, Huel. Blende, Chalcocite, Chalcopy- rite, Fluor, Melaconite, Mis- pickel, Petroleum ? Pyrites, Tennantite. Do. Killiwerris. Chalcopyrite, Galena. Do. PENNANCE. Copper. Chlorite, Chalcopyrite, Erubes- cite. Do. Penstruthal and Copper Huel Buller. and Tin. Do. Ting Tang. Chalcocite, Chalcopyrite, Chal- cophyllite, Chessylite, Chlorite, Chrysocolla, Clinoclase, Cu- Erite, Limonite, Malachite, Me- iconite, Melanterite, Olivenite, Pitchblende, PHARMACOSIDE- RITE, Lithomarge, Pyrites, Torbernite, Orthoclase. Do. TRESAVEAN and Tin and Blende, Chalcocite, Chalcopyrite, TRETHARRUP. Copper. Chlorite, Copper, Epidote?Eru- bescite, Fahlerz, Fluor, Galena, Goslarite, Hornblende, Magne- tite, Melaconite, Pyrites, Ten- nantite. Do. Trethellan. Copper. Chalcocite, Goslarite. Do. United Mines. Copper. Cassiterite, BARYTES, Rock Crys- tal. St. Day. POLDICE. Tin. Bitumen, Cassiterite, Copper, Chalcopyrite, Galena, Pyrites, Sulphur ? Wolfram, Wolframite. CHAPTER V. -DISTRIBUTIVE. 57 LIST OP MINES, &c. CORNWALL, KIBKIER, East Division (Cont.) Parish. Locality. Produce of Mines. More remarkable Minerals. St. Day (Con.] Vogue. _ KAOLIN. Gluvias. EOSCROW UTD. Chlorite, Mispickel, Pitchblende. Do. Burnt House. Magnetite. Do. Treluswell. Adularia? Hornblende. Perran - ar- Kerjiliack. Graphite, in an elvan. worthal. Constantine. CONSTANTINE Iron. LlMONITE. MINE. Do. LOVELL, NEW Tin. Cassiterite. EAST HUEL. Do. Granite Quarries Fine imbedded crystals of OR- THOCLASE ; occasional crystals of Beryl and Topaz, but very rare. Mawnan. Cliffs on sea shore Aragonite, Calcite, Chalcopyrite, Oxide of Zinc. Mabe, Granite Quarries Fine Orthoclase in the Granite, oc- casionally Schorl; very rarely Beryl and Topaz. Budock. Budock Vean. Bournonite, Galena. Do. Falmouth. Maenporth. Swanpool, Mine. Lead. Rock Crystal, Calcite, Aragonite? Galena, Pyrites, Rock Crystal. Mylor. Trefusis, Huel. Lead. Galena. CORNWALL, PYDAR, West Division. Parish. Locality. Produce of Mines. More remarkable Minerals. St. Agnes. Barrow, Huel. Tin. Blende, Cassiterite, Scheelite, Pyrrhotite. Do. Basset, Huel. Copper. Argentite, Copper, Cuprite, Ma- lachite, Pitchblende, Torbernite Do. BLUE HILLS. Tin. Cassiterite. Do. CHARLOTTE, HUEL Copper. Cassiterite. Do. CHIVERTON, GRT. Lead. Galena. WEST. Do. Clarence, Huel. Tin. Cassiterite, Smaltite. Do. Cligga Head. Cassiterite, KAOLIN, Chalcopy- rite, Wolfram. Do. Coates, HueL Tin. Agnesite, Bismite, CASSITERITE, Mica, Orthoclase ; remarkable pseudomorphs of Cassiterite after Orthoclase, Schorl. Do. COIT, HUEL. Tin. Cassiterite. Do. Devonshire, Huel Tin. Chalcopyrite, Cassiterite, Fluor, Pyrites. Do. FRIENDLY MINES Tin. Cassiterite. Do. Hallenbeagle and East Downs. Copper and Tin. Chalcopyrite, Pyrites. Do. Do. James, Huel. Kind, Huel. Tin. Torbernite, Chalcopyrite. Apatite, Chalybite, Covellite, Pyrrhotite, Topaz, VIVIANITE. Do. KITTY, HUEL. Tin. Blende, CASSITERITE, Chalcopy- rite, Chlorite. 58 CHAPTER V. DISTRIBUTIVE. LIST OF MINES, &c. COENWALL, PYDAK, West Division (Cont.j Parish. Locality. Produce of Mines. More remarkable Minerals. St. Agnes. KITTY, WEST Tin. Bismite, Cassiterite, STANNITE. (Gont.) HUEL (formerly Huel Rock). Do. Music, Huel. Copper. Copper, Chalcocite, Chalcopyrite, Cuprite, Malachite. Do. PENHALLS. Tin. Cassiterite. Do. Do. POLBERKOW. Polberrow, West. Tin. Tin and Cassiterite, Chalcopyrite, Copper. Cassiterite, Chalcopyrite, Fluor. Do. Polbreen. Copper. Tin. Cassiterite. Do. PRUDENCE, HUEL. Blende, Chalcopyrite, Towanite. Do. Pye, Huel. Cassiterite. Do. To wan, Huel. Tin. Blende, Cassiterite, Chalcopy- rite, Chalybite, Chlorite, Li- monite. Do. TOWAN, SOUTH Copper. Bitumen, Chalcopyrite, Cha- Do. HUEL. lybite, Chlorite, Limonite, Py- rites. Do. TOWAN, NEW Tin and Cassiterite, Chalcopyrite, Pyrites, Do. HUEL. TREVAUNANCE, Copper. Tin. Cassiterite, Fahlerz, Fluor, Topaz. HUEL. Perranzabuloe CHIVERTON (Old Silver-Lead Galena. Cornubian). Do. CHIVERTON, EAST Silver-Lead Galena. Do. CHIVERTON MOOR Silver-Lead Galena. Do. CHIVERTON, NEW Copper, Lead Blende, Cerussite, Chalcopyrite, (Huel Anna). and Zioc. Galena. Do. CHIVERTON, NEW Lead, Zinc, Blende, Cassiterite, Chalcopy- CONSOLS (Bud- Tin. rite, Galena, Pyrites. nick Consols). Do. CHIVERTON, GRT. Lead. Blende, Chalcopyrite, Dolomite, SOUTH. Galena. Do. CHIVERTON UTD. Lead. Galena. Do. CHIVERTON VAL- Silver-Lead Galena. LEY. Do. CHIVERTON, WEST Lead, Zinc. BLENDE, CHALCOPYRITE, GALENA. Do. Duchy and Peru. Iron. Chalcopyrite, Chalybite, Galena, MARCASITE. Do. Golden Consols. Tin. Cerussite, Galena, Pyromorphite, Rock Crystal, Silver. Do. GOLDEN, EAST Lead. Galena. HUEL. Do. Great St. George. Copper. Blende, Calamine, Chalcocite, Chalnopyrite, Copper, Limo- nite, Melaconite. Do. GRT. ST. GEORGE, Blende. WEST. Do. Hope, Huel. Silver-Lead BLENDE, GALENA, Chalcopyrite. Do. JEWELL, EAST. Tin and Cassiterite, Chalcopyrite. Copper. Do. Mexico, Huel. Argentite, Galena, Kerate, Silver Do. MINERAL BOTTOM Lead. Galena, Blende. Do. Penhale. Lead. Galena. Do. PERRAN CONSOLS Tin. Cassiterite. (Huel Vlow). Do. PERRAN HUEL Lead. Galena. VYVYAN. CHAPTER V. DISTRIBUTIVE. 59 LIST OF MINES, &c. CORNWALL, PYDAR, West Division (Cont.) Parish. Locality. Produce of Mines. More remarkable Minerals. Perranzabuloe (Cont.) PERRAN SAINT GEORGE. Copper. Blende, Chalcocite, Chalcopyrite, Copper, Limonite, Melaconite. Do. RETALLACK, GRT. Lead, Zinc. Blende, Galena, Hornblende, Silver. Do. RETALLACK,NTH. Do. VIRGIN, HUEL. Lead. Galena, Marcasite, Cubert. PENHALE AND Lead. Blende, Galena. LOMAX. Newlyn. CARGOLL. Silver-Lead Blende, ^ Chalcopyrite, Galena, Marcasite. Do. Fiddler's Green. Do. Rose, Huel. Lead. Galena, Pyrites. Do. ROSE AND CHI- Lead. Blende, Galena. VEHTON. Crantock. TREREW. Lead. Galena. CORNWALL, PYDAR, East Division. Parish. Locality. Produce of Mines. More remarkable Minerals. St. Enoder. CHYTANE. Tin and Cassiterite, KAOLIN. China-clay. St. Columb. ROYALTON. Tin. Cassiterite. Do. TREWORLOCK. Lead. Galena. Do. Lanivet. Trugoe. MULBERRY HILL. Tin. Bismuth, Erythrite, Jasper, Opal. Cassiterite. Do. RETIRE. Iron. Hematite, Limonite. Do. REPERRY. Tin. Antimonite, Berthierite, Cas- siterite, Cervantite, Jameso- nite. Padstow. ST. ISSEY. Copper, Chalcopyrite, Galena. Lead. Do. TRELEATHER, Copper, Chalcopyrite, Galena. NORTH. Silver-Lead. St. Merryn. 1 Bournonite. CORNWALL, POWDER, West Division. Parish. Locality. Produce of Mines. More remarkable Minerals, St. Feock. St. Kea. Do. Carnon Stream Works. CREEGBRAWSE & PENKIVELL. Falmouth, Huel. _ Copper and Tin. Silver-Lead, and Man- ganese. CASSITERITE, GOLD. Chalcopyrite, Cassiterite, PY- RITES. Blende, Cassiterite, Cerussite, Chlorite, Erubescite, Galena, Pharmacosiderite, PYRITES, Py- romorphite, Silver, VIVIAMTE. 60 CHAPTER V. DISTRIBUTIVE. LIST OF MINES, &c. CORNWALL, POWDER, West Division (Cont.) Kenwyn. BOSCAWEN. Copper, Chalcopyrite, Blende. Tin, Zinc. Do. JANE, NORTH. Tin, Silver- Cassiterite. Lead. Do. Unity Wood, Cassiterite, Chalcopyrite, Chlo- Huel. rite, Fluor, Pyrites, Schorl. St. Erme. Garras. Lead. ALLOPHANE, Blende, Calcite, Dolomite, Galena. Ladock. Cassiterite, Gold, Hematite, Li- monite, Pyrites. Veryan. Pennare Point. Asbestos, Hornstone, Steatite. CORNWALL, POWDER, East Division. Parish. Locality. Produce of Mines. More remarkable Minerals. St. Dennis. Hendra. Mica. Do. Kaolin, Cassiterite. St. Stephens. CROW HILL, NEW Lead. Galena, Gold? Pyrites. Do. Dowgas. Actinolite, Cassiterite, Horn- blende, Kaolin, Pyrites, SchorL Do. FORTESCUE,HUEL Do. GRENVILLE, HUEL Tin. Cassiterite. Do. Terras. Tin. Kaolin, Cassiterite. Gorran. Gorran Haven. Calcite. St. Ewe. CHANCE, HUEL. ANNABERGITE, Chalybite, Mille rite, Niccolite. Do. Pengelly Mine. ANNABERGITE, Chalybite, Mille - rite, Niccolite. St. Mewan. Brecon, Cam. Cassiterite, Gold, Silver. Roche. BEAM MINE. Tin. Cassiterite, Kaolin, Melaconite, Olivenite, Pharmacosiderite, Talc, Wolfram, Wavellite? Do. BRYNN MINE. Tin. Cassiterite. Do. BRYNNROYALTON Tin. Cassiterite. Do. Cost all Lost. Bismite, Cassiterite. Do. ROYALTON, GRT. Tin. Cassiterite. St. Austell. CARCLAZE. Tin and Kaolin. Cassiterite, Galena, Gilbertite, KAOLIN, Schorl. Do. Carvath United. Copper Chalcocite, Cuprite. and Tin. Do. CHARLESTOWN Tin and Actinolite, Cassiterite, Chaly- UTD. MINES. Copper. bite, Limonite, Serpentine? Do, CONSOLIDATED, Annabergite, Barytes, Cobaltite, ST. AUSTELL. Copper, Pitchblende, Smaltite. CHAPTER V. DISTRIBUTIVE. 61 LIST OF MINES, &c. CORNWALL, POWDER, East Division (Gout.) Parish. Locality. Produce of Mines. More remarkable Minerals St. Austell Crinnis. Copper. Chalcopyrite, Chalybite, Childre- ( Cont. ) nite, Copper, FAHLERZ, Galena, Scorodite, Silver, Pyrites. Do. CUDDKA. Tin. Cassiterite. Do. ELIZA, HUEL. Tin and Cassiterite, Chalcopyrite. Copper. Do. ELIZA CONSOLS, Copper Cassiterite, Chalcopyrite. HUEL. and Tin. Do. GOONBAKKOW. Tin and Cassiterite, Kaolin, Zippaeite ? Kaolin. Do. GOVEB. Tin. Cassiterite. Do. GKEAT DOWGAS. Tin. Bismuth, Bismuthinite, Cassi- terite, Copper, Fluor. Do. Grt. Hewas Utd. Tin. Cassiterite, Liroconite, Mispickel. Do. Hill Mine. Tin. Cassiterite, Orthoclase, Tourma- line, Topaz. Do. MINEAR DOWNS. Cassiterite. Do. Pembroke. Copper. Chalybite, Chalcopyrite, Chalco- cite, Copper, Kaolin, Melaco- nite, Pyrites. Do. Pentewan. Stream Tin, Gold. Do. POLGOOTH. Tin. Amethyst, Calcite, Cassiterite, Chalcopyrite, Chlorite, Dolomite Erythrite, Pyrites, Smaltite. Do. POLMEAR, HUEL. Copper Chalcopyrite, Pyrites. and Pyrites. Do. KOCK HILL. Cassiterite. Do. RUBY & KNIGH- Iron. LIMONITE, Hematite, Black TOR. Quartz. Do. SHILTON (Bon- Tin. Cassiterite. ney). Do. Stenna Gwynn. Tin. Apatite, Autunite, Oassiterite, FLUELLITE, FLUOR, Gilbertite, Mesolite? Natrolite, Opal, Stan- nite, Talc, Tavistockite, Torber- nite, Wavellite? Wolfram. Do. Trenanon. Blende. Do. Virgin, Huel. Tin. Cassiterite. St. Blazey. East Crinnis. Copper. Blende, Chalcocite, Chalcopyrite, Chalybite, Copper, Melaconite, Pyrites, Rock Crystal. Do. PAR CONSOLS. Copper Blende, Cassiterite, Chalcopy- and Tin. rite, Chlorite. Do. PEMBROKE, NEW. Copper and Tin. Cassiterite, Chalcopyrite. Do. Tywardreath. PEMBROKE, OLD. Fowey Consols. (Lanescot.) Copper. Copper. Chalcopyrite. Actinolite, Antimonite, Apatite, Bismuthinite, Blende, Cala- mine, Chalcocite, Chalcopyrite, Chalcotrichite, Chalybite, Co- baltite, Copper, Cuprite, FRAN- COLITE, Niccolite, Magnetite, Marcasite, Melaconite, Melan- terite, Millerite, Pyrites, Silver, Stannite, Wood Tin. Do. FOWEY CONSOLS, Copper. Chalcopyrite. SOUTH. 62 CHAPTER V. DISTEIBUTIVE. LIST OP MINES, &c. CORNWALL, POWDER, East Division (Cont.) Parish. Locality. Produce of Mines. More remarkable Minerals. Fowey. Menabilly. _ Molybdenite. Luxulyan. Luxulyan, Quar- ORTHOCLASE, SCHORL. ries near. Lanlivery. MAUDLIN MINES. Copper and Tin. Calcedony, Cassiterite, Chaly- bite, Chlorite, Covellite, Cron- stedtite, Fluor, Garnet, Jasper, Melanterite, Mispickel, Opal, Pyrites, Pyrrhotite, Scheelite, Wolfram. Do. Prideaux Wood Tin. Cassiterite. Mine. Lostwithiel. FORTESCUE, NTH. Lead. Galena. HUEL. Do. RESTORMEL. Iron. AGALMATOLITE, Amethyst, Ba- rytes, Bismuth, Bismite, Goe- thite, Hematite, LIMONITE, Manganite, PSILOMELANE, Pyro- lusite, Rock Crystal, Zippseite. Do. Terrace Hill Axinite. Quarry. CORNWALL, TRIGG. Parish. Locality. Produce of Mines. More remarkable Minerals. St. Minver. Pentire Glaze. Antimonite, CERUSSITE, Cervan- tite, Pyrolusite. Endellion. Boys, Huel. Antimonite, BOURNONITE, Cer- vantite, Erubescite, Jamesonite, Mimetite. Do. Port Isaac. Antimonite, Cervantite, Jameso- nite. Do. Port Quin Cliffs. Jamesonite. Do. ROYAL SAMPSON. Silver-Lead. Galena. Do. Trevinnock. Bleinierite, Cervantite, Jameso- nite. St. Kew. Pendogget. Anglesite, Antimonite, Jameso- nite. Do. PENGENNA. Lead. Galena. Bodmin. Bodmin Moor. Stream Tin. Do. ESTHER UNITED, Tin. Cassiterite. HUEL. St. Breward. ONSLOW CONSOLS, Copper. Chalcopyrite. GREAT. St. Teath. Do. ARCHIE, HUEL. OLD TREBURGETT Copper, Lead Lead, Silver. Chalcopyrite, Galena. Blende, Chalcopyrite, Pyrites, Polytelite. Do. TREGARDOCK. Lead, Copper Chalcopyrite, Galena. CHAPTER V. DISTEIBUTIVE. 63 LIST OP MINES, &c. CORNWALL, WEST. Parish. Locality. Produce of Mines. More remarkable Minerals. St. Veep. _ Asbestos. Lanreath. HERODSFOOT. Silver-Lead. Bournonite, CALCITE, Chalcopy- rite, Fahlerz, Galena, Horn- stone, Pyrites. Duloe. HEEODSFOOT, Silver-Lead. Calcite, Galena. SOUTH. Liskeard. AMBROSE LAKE. Tin. Cassiterite. Do. Looe Mills Hill Anatase. Quarry. Do. St. Neot. Tin. Cassiterite. St. Cleer. CARADON CON- Copper. Chalcopyrite, Cuprite. SOLS. Do. CARADON, SOUTH. Copper. Chalcocite, Chalcopyrite, Cu- prite, Fluor. Do. CARADON, WEST. Copper. Chalcocite, Chalcopyrite, Cu- prite, Copper, Fluor. Do. Cheesewring. Actinolite, Asbestos, Orthoclase, Soapstone? Schorl. Do. Do. CRADDOCK MOOR. GLASGOW CARA- Copper. Copper. Chalcopyrite, Cuprite. Chalcopyrite, Cuprite. DON CONSOLS. Do. GONAMENA. Copper. Chalcopyrite, Cuprite. Do. St. Neot. Ludcott, Huel. HAMMETT. Tin. Pyrargyrite, Silver. Cssiterite. Do. TIN VALLEY. Tin. Cassiterite. Do. TREVENNA, HUEL Tin and Cassiterite, Chalcopyrite. Warleggan. GRT. TREVEDDOE Copper. Tin. Cassiterite. AND CABILLA. CORNWALL, LESNEWTH. Parish. Locality. Produce of Mines. More remarkable Minerals. Tintagel. Cliffs. _ Albite, Anatase, ARAGONITE Brookite? Do. DELABOLE SLATE Adularia, Albite, Anatase, Cal- QUARRIES. cite, Goethite, ROCK CRYSTAL, Rutile? Do. KING ARTHUR Silver-Lead. Galena. MINE. Forrabury. Cliffs. Anthracite. Do. Boscastle. Graphite. Davidstow. Hematite, Limonite. Laneast. Lettcott. Manganite, Psilomelane. Alternun. Stream Tin, Gold. 64 CHAPTER V. DISTRIBUTIVE. LIST OF MINES, &c. CORNWALL, EAST. Parish. Locality. Produce of Mines. More remarkable Minerals. Launceston. Do. Five Lanes. Pollaphant. Hornblende. Calcite, Serpentine, STEATITE. Callington. Creva Wood. Pyrolusite. Do. COLQUITE AND Copper. Chalcopyrite. CALL. UTD. Do. Duchy Huel. Argentite, Kerate, Pyrargyrite, Silver. Do. DEER PARK. Tin. Cassiterite. Do. EXCELSIOR. Tin and Cassiterite, Chalcopyrite. Copper. Do. George and Char- Bismuthinite, Childrenite, Chlo- lotte. rite. Do. FLORENCE, HUEL. Copper. Chalcopyrite. HATE VALLEY. Tin. Cassiterite. Do. HOLMBUSH AND Copper. Chalcopyrite. Do. KELLY BRAY. Do. Do. KELLY BRAY. NEW GREAT CON- Silver-Lead. Tin and Chalcopyrite, Galena. Cassiterite, Chalcopyrite. SOLS. Copper. Do. PRINCE OF WALES Copper. Chalcopyrite. SOUTH. Do. PRINCESS OF Copper Cassiterite, Chalcopyrite. WALES. and Tin. Do. REDMOOR. Copper. Cassiterite, Chalcopyrite. Do. St. Vincent, ARGENTITE, Chalcopyrite, KE- Huel. RATE, SILVER. St. Ive. CARADON, GRT. Copper. Chalcopyrite. Do. GILL, HUEL. Copper Chalcopyrite, Galena. and Lead. Do. GILL, GLASGOW Lead. Galena. HUEL. Do. IDA, HUEL. Silver-Lead. Galena. Do. TRELAWNEY, Copper. Blende, Barytes, Chalcopyrite, NEW. Galena, Fluor, Hornstone. Linkinhorne. Do. CARADON, EAST. CARADON AND Copper. Copper Chalcopyrite, Cuprite. Blende, Chalcopyrite. PH(ENIX. and Zinc. Do. Do. MARKE VALLEY. PHCENIX. Copper. Copper and Tin. Chalcopyrite, Cuprite. Cassiterite, Chalcopyrite, Chal- cotrichite, CUPRITE, Copper, Chrysocolla, Malachite, Oli- venite. Do. PHCENIX, EAST. Copper. Chalcopyrite. Do. PHOZNIX, WEST. Copper. Chalcopyrite. Do. Rose Down, West Copper. Chalcopyrite. Stokeclims- KITT HILL. Tin and Cassiterite, Chalcopyrite. land. Copper. Do. KITT HILL, EAST. Tin and Cassiterite, Chalcopyrite. Copper. Do. KITT HILL, STH. Tin. Cassiterite. Calstock. ARTHUR, HUEL. Copper Bismuthinite, Cassiterite, Chal- and Tin. copyrite. Do. Brothers, Huel. Copper. ARGENTITE, Blende, Chalybite, Galena, PYRARGYRITE, SILVER. Do. CALSTOCK CON- Copper. Chalcopyrite. SOLS. CHAPTER V. DISTRIBUTIVE. 65 LIST OF MINES, &c. CORNWALL, EAST (Cont.) Parish. Locality. Produce of Mines. More remarkable Minerals. Calstock DBAKEWALLS. Tin and Cassiterite, Molybdenite, Wol- (Cont.) Do. DEAKEWALLS, Copper. Tin. fram, Wolframite. Cassiterite. WEST. Do. GUNNISLAKE. Copper. Antimonite, Chalcocite, Chal- cophyllite, Chrysocolla, Copper, Cuprite, Cyanosite, Libethenite, Liroconite, Malachite, Melaco- nite, Olivenite, Torbernite, Wolfram. Do. GUNNISL A K E CLITTEKS. Copper and Tin. Chalcopyrite. Do. HAKEWOOD CON- Copper. Chalcopyrite. SOLS. Do. HAWKMOOR. Copper. Chalcopyrite. Do. KINGSTON Copper. Chalcopyrite. DOWNS. Do. Lee, Huel. Antimonite, Cervantite, Galena, Jamesonite. Do. Do. OKEL TOB. PRINCE OF WALES Copper. Copper Chalcopyrite. Chalcopyrite. and Tin. Do. PRINCE OF Copper. Chalcopyrite. WALES, WEST. Menheniot. Do. Clicker, Tor. MARY ANN, Silver- Asbestos, Calcite, Serpentine. BARYTES, Calcite, Pyrites, Rock HUBL. Lead. Crystal. Do. TRELAWNY, HUEL Silver- Barytes? Calcite, Galena. Lead. Do. Treweatha. Silver- Galena. Lead. 66 CHAPTER V. DISTRIBUTIVE. DEVONSHIRE. (In Devon, as the Localities are more widely separated than in Cornwall, they are somewhat arbitrarily arranged.) SOUTHERN PARLIAMENTARY DIVISION. Situation or Parish. Locality. Produce of Mines. More remarkable Minerals. Lifton. Harris, Huel. Silver-Lead. Galena. Do. HEALE. Manganese. Psilomelane, Pyrolusite. Do. Henry, Huel. Manganese. Psilomelane, Pyrolusite. Do. LIFTON MINES. Manganese. Psilomelane, Pyrolusite. Do. Mary Emma, Tin. Cassiterite. Huel. LewTren chard LEW WOOD. Manganese. Psilomelane, Pyrolusite. Okehampton. Amethyst, Andalusite, Axinite, Chiastolite ? Jasper, Opal, Eock Crystal, Schorl, Do. BELSTONE CONS. Copper. Chalcopyrite, Garnet, Limonite. Do. Maria, East Huel. Copper. Chalcopyrite. Do. Copper Hill. Axinite, Garnet. Do. FOREST HILL. Tin and Axinite, Cassiterits, Galena, Lead. Garnet. Do. FORSDON MINE. Copper. Axinite, Chalcopyrite, Garnet. Do. Holstock. Chiastolite ? Do. Ivey Tor. Copper. Axinite, Bismuthinite, Chalcopy- rite, Marcasite. Do. Meldon Quarry. Garnet, Pyrrhotite. Do. Sticklepath. Actinolite, Axinite, Hornblende. Do. Lidford. Zeal Consols, Sth. Frederick, Huel. Copper. Tin. Chalcopyrite. Cassiterite. Do. Lidford Consols. Tin. Cassiterite. Do. Swincombe Vale. Tin. Cassiterite. Marystow. ALLIFORD. Manganese. Psilomelane, Pyrolusite. Do. CALLACOMBE. Copper Blende, Chalcopyrite. and Blende. Do. Dippertown. Manganese. Psilomelane, Pyrolusite. South Syden- Concord. Silver-Lead Chalcopyrite, Galena. ham. & Copper. Milton Abbot. CAWSAND VALE. Copper. Chalcopyrite. Do. Chillaton. Manganese. Psilomelane, Pyrolusite. Do. Hogston. Manganese. Psilomelane, Pyrolusite. Lamerton. CALLACOMBE,EST. Copper. Chalcopyrite. Do. CARDWELL. Manganese. Psilomelane, Pyrolusite. Do. MARIA, WEST & FORTESCUE. Copper and Lead. Chalcopyrite, Galena. Mary Tavy. Betsy, South Huel. Copper and Lead. Do. Devon Huel Copper. Union. Do. FRIENDSHIP, Copper. Axinite, Blende, Calcite, CHAL- HUEL. COPYRITE, Chalybite, Chlorite, Fluor, Galena, Pyrites, KOCK CRYSTAL, Scheelite, Wolfram? Do. Friendship, Nth. Huel. Copper and Lead. Chalcopyrite, Galena. Do. Peter Tavy and Copper. Chalcopyrite. Mary Tavy Cns. CHAPTER V. DISTRIBUTIVE. 67 LIST OF MINES, &c. DEVONSHIRE, SOUTHERN DIVISION (Cont.) Situation or Parish. Locality. Produce of Mines. More remarkable Minerals. Mary Tavy PRINCE ARTHUR Silver-Lead. Chalybite, Galena, Limonite, (Cont.) CONSOLS (Old Vivianite. Huel Betsy.) Tavistock. BEDFORD CONLS. Copper. Chalcopyrite. Do. BEDFORD UNITED. Copper. Chalcopyrite, CHALCOTRICHITE, Chalybite, Clinoclase, CUPRITE, Olivenite, Pyrites, Torbernite. Do. Black Down. Niccolite, PSILOMELANE, PYROLU- SITE, Rhodonite. Do. Brent, Tor. Actinolite, Axinite, Garnet, Jas- per, Psilomelane, Pyrolusite. Do. COURTNEY, HUEL. Copper. Chalcopyrite. Do. CREBOR. Copper. Bitumen, Chalcopyrite, Chaly- bite, Childrenite, Chlorite, Copper. Do. CRELAKE. Copper. Chalcopyrite. Do. Crowndale. Copper. Chalcopyrite, Marcasite. Do. DEVON & CORN- Copper. Antimonite, Bismuthinite, Chal- WALL UNITED. copyrite, Childrenite, Chlorite. Do. Devon & Courte- Copper. CHALCOPYRITE, Copper, Galena. nay. Do. DEVON GREAT Copper. CHALCOPYRITE, Copper, Mispickel CONSOLS. Do. Devon Gt. Con- Copper. Chalcopyrite. sols, East. Do. Gawton. Copper. Chalcopyrite. Do. GUNNISLAKE, Copper. Chalcopyrite. EAST, & SOUTH. BEDFORD. Do. NEW GT. CONSLS. Copper. Chalcopyrite. Do. KUSSELL, HUEL. Tin. Cassiterite. Do. Russell, Est. Huel Copper. Chalcopyrite. Do. KUSSELL, NEW Copper. Chalcopyrite. EAST HUEL. Do. Do. Tavy Consols. United Mines. Copper. Tin and Chalcopyrite. Cassiterite, Chalcopyrite. Copper. Do. "Wills worthy CHALCOPYRITE, Erythrite, Silver. Mine. Bickleigh. Bickleigh Vale, Huel Phoanix. Copper and Tin. Cassiterite, Chalcopyrite. Sampford Spi- Huckworthy Copper. Chalcopyrite. ney. Bridge. Do. Kobert, Huel. Copper. CHALCOPYRITE, Limonite, Pyrites, Rock Crystal. Do. Robert, North Copper. Chalcopyrite. Huel. Prince Town. WHITE WORKS. Tin. Cassiterite. Buckland Buller & Bertha. Copper. Chalcopyrite. Monachorum. Do. Bertha, East. Copper. Chalcopyrite. Do. Devon Poldice. Tin & Cop. Cassiterite, Chalcopyrite. Do. Devon Huel Bul- Copper. Chalcopyrite. ler. Do. Franco, Huel. Copper. Cassiterite, Chalcopyrite, Chaly- bite, Fluor, FRANCOLITE. 68 CHAPTER V. DISTEIBUTIYE. LIST OP MINES, &c. DEVONSHIRE, SOUTHEKN DIVISION (Cont.) Situation or Parish. Locality. Produce of Mines. More remarkable Minerals. Buckland Lady Bertha. Copper. Chalcopyrite. Monachorem (Cont.) . Do. Lady Bertha, Copper. Chalcopyrite. South. Do. VIRTUOUS LADY. Copper. Anatase, Brookite? CHALCOPY- RITE, Chalybite, Chlorite, Fluor, MARCASITE, Mispickel, Pyrites, Titanite. Beerferris. Beeralston Mines. Silver-Lead. Anglesite, Blende, Bournonite, Calcite, Calcedony, Chalcopy- rite. Chalybite, Dolomite, Fahlerz, FLUOR, Galena, Horn- stone, Mimetite, Pyromorphite, Pyrrhotite. Do. Queen of Tamar. Copper Chalcopyrite, Galena. and Lead. Do. South Hooe. Dolomite, Fluor. Do. SOUTH WARD. Silver-Lead. Galena. Do. Tamar Consols. Silver-Lead. Blende, Cassiterite, CHALCOPHYL- LITE, Fluor, Galena, MARCASITE, Mispickel, Rock Crystal. Do. Tamar, East. Lead. Anglesite, Cerussite, Chessylite, Galena, Hornstone, Malachite. Do. TAMAR VALLEY. Silver-Lead. Galena. Whitchurch. Sortridge Consls. Copper. Chalcopyrite. Plymouth. Many Quarries. CALCITE. Plympton. Chalybite, Kaolin. Do. BOTTLE HILL, Tin. Cassiterite. EAST. Do. MARY HUTCHINGS Tin. Cassiterite. HUEL. Do. Shaugh. Iron. Chalybite, Limonite. Do. Sydney, Huel. Tin. Cassiterite. Ivybridge. Chiastolite ? Orthoclase. Dartmoor. Andalusite? Cassiterite, Garnet, Hematite, Hornblende, Tour- maline. Do. Haytor. Agate, Calcedony, Garnet, Hay- torite, Hornblende, Magnetite, Orthoclase, Opal. Do. Sheepstor. Cassiterite, Gold. Buckfastleigh. Aragonite, Hematite, Limonite, Malachite. Do. BROOKWOOD. Copper. Chalcopyrite. Do. EMMA, HUEL. Copper. Chalcopyrite. CHAPTER V. DISTRIBUTIVE. 69 LIST OF MINES, &c. DEVONSHIRE, EAST DIVISION. Situation or Parish. Locality. Produce of Mines. More remarkable Minerals. Chagford. VITIFER CONSOLS, Copper. Chalcopyrite, Schorl. NEW. M o r e t o n - Gidleigh. Kock Crystal. hempstead. Christow. EXMOUTH. Copper and Chalcopyrite, Galena. Silver-Lead. Do. Exmouth. North Copper and Huel. Silver-Lead. Do. Exmouth, South Silver-Lead. Huel. Do. FRANK MILLS. Silver-Lead. Galena. North Bovey. BIRCH TOR, NEW Tin. Cassiterite. and VITIFER. Do. Birch Tor, East. Tin. Cassiterite. Do. King's Oven. Tin. Cassiterite. Bovey Tracey. Apatite, Diallogite, Hornblende, LIGNITE, Lithomarge, Mica, Orthoclase, RETINUE, TOURMA- LINE. Do. DEVON HUEL Copper. Chalcopyrite. FRANCES. Do. Yaruer. Copper and Mundic. Chalcopyrite, Pyrites. Lustleigh. Beryl, Garnet, Hennatite, Opal. Ilsington. Atlas. Tin & Iron. Cassiterite, Limonite. Do. Hatherley. Iron. Limonite, Magnetite. Do. Sigford. Copper and Tin. Cassiterite, Chalcopyrite. Do. Smallacombe. Iron. Limonite, Hematite. Ashburton. Ashburton Cons. Copper. Chalcopyrite. Do. Ashburton Mine. Cassiterite. Do. Ashburton Untd. Tin and Cassiterite, Chalcepyrite. Copper. Do. Ashburton, West. Copper and Tin. Cassiterite, Chalcopyrite. Do. Buckland in the Magnetite. Moor. Do. Devon Gt. Huel Ellen. Copper and Tin. Cassiterite, Chalcopyrite. Do. Do. Devon, New. Smith's Wood. Copper. Chalcopyrite. Cassiterite. Do. United, Dart. Copper. Chalcopyrite. Do. VICTORIA (Arun- Copper. Chalcopyrite. del.) Do. Torquay. Victoria, New. Babbicombe Bay. Copper. Chalcopyrite. BARYTES, Beekite, Calcite. Do. Mary Church. Agate. Do. Torbay. Aragonite, BEEKITE. Do. Torbay Mine. Iron. Hematite, Limonite. Paignton. GTMTON. Iron. Hematite, Limonite. Brixham. FIVE ACRE. Iron. Hematite, Limonite. Do. PROSPER, HUEL. Iron. Hematite, Limonite. Do. PARKINS. Iron. Hematite, Limonite. Do. SHARPHAM. Iron. Hematite, Limonite. Dawlish. Calcite, MURCHISONITE. Chudleigh. Apatite, Kalinite, Petroleum, Psilomelane, Schorl. 70 CHAPTER V. DISTEIBUTIVE. LIST OP MINES, &c. DEVONSHIRE, EAST DIVISION (Cont.) Situation or Parish. Locality. Produce of Mines. More remarkable Minerals. Chudleigh (Cont.) Exeter. Do. Budleigh Sal- terton. Sidmouth. Axminster. Hennock. Haldon. Heavitree. Seaton. BAKYTES, Blende, Cerussite, Ga- lena, Hematite, Malachite. Chert, Flint. Orthoclase, MURCHISONITE. Agate, Orthoclase. Celestite, Flint. Asbestos. DEVONSHIRE, NORTHERN PARLIAMENTARY DIVISION. Situation or Parish. Locality. Produce of Mines. More remarkable Minerals. Buckland _ Hematite, Jasper, Limonifce. Br ewer. Do. Orleigh Court. Chert, Flint, Psilomelane. Bideford. Anthracite, Hematite, Psilome- lane. Ilfracombe. Aragonite, Hematite, Millerite. Do. Combmartin Silver-Lead. Aragonite, Antimonite, Blende, Mines. Calcite, Chalcopyrite, Chessy- lite, Fahlerz, Galena, Hematite, Malachite, Marcasite, Millerite, Pyrites, Rock Crystal, Silver, Umber, Yellow Ochre. Do. West Down. Hematite, Psilomelane. Barnstaple. Abbotsham. Anthracite. Do. Bickington. Pyrites. Do. Bishop's Tawton. Pyrites. Do. Bratton Fleming. Hematite, Limonite. Do. East Down. Hematite, Limonite, Psilomelane, Umber, Yellow Ochre. Do. Georgeham. Hematite, Limonite, Psilomelane, Pyrolusite. Do. Hawkridge "Wood Anthracite. Do. Landkey. Blende, Galena. Do. Viveham. Hematite, Limonite,Psilomelane, Pyrolusite, Pyrites. Nth. Moulton. BAMPFYLDE, NEW Copper. Chalcopyrite. Do. BRITTANIA and Copper. Chalcopyrite, Erubescite, Fah- PRINCE REGENT. lerz, GOLD. Do. Molland Mine. Copper. Chalcopyrite, Fahlerz. Sth. Moulton. Filleigh. WAVELLITK. Newton St. Hematite, Psilomelane. Cyres. Upton Pyne. Manganite, PSILOMELANE, PYRO- LUSITE, Rhodonite, Wad. Collumpton. Anthracite. Blackdo wn Agate, Chert, Flint. Hills. Ex moor. Chalybite, Goethite, Limonite. Lundy Island. Chalcopyrite, Hornblende, Mag- netite, Orthoclase, Rock Crys- tal, Topaz, Tourmaline. CHAPTER VI. PABAGENETIC. 71 CHAPTER VI. PARAGENETIC That the composition of a mineral lode often varies with a variation of the enclosing country is a very old observation. The subject was largely considered by Mr. W. J. Henwood, in his great work on the Metalliferous Deposits of Cornwall and Devon ; and, although it well deserves further elucidation, this belongs rather to a geological than to a mineralogical work. A more strict paragenesis would deal with those groups of minerals which are immediately associated with each other, or even in contact ; and fortunately such an enquiry may be conveniently prosecuted wherever a well-selected series of mineral specimens exists. The object of this chapter is rather to draw popular attention to this branch of the subject than to follow it up in detail, as many more observations should be specially made in this direction before any very definite laws can be announced. It is well-known, however, that certain minerals are, to use a miner's term, "congenial" to others ; and a few such observations are here set down. Of all the minerals known in the two western counties, Quartz is the most widely diffused, and most generally associated with other minerals. So general is its occurrence, that its peculiar varieties must be studied in order to lead to any definite results. The following examples of paragenesis will be recognised as common ; but it would be well if students would carefully register and accumulate observations on this part of the subject, and make them publicly known through any con- venient channel. QUAKTZ is commonly associated with Orthoclase. Mica. Schorl. Chlorite. ,, Chalybite. Calcite. ,, Dolomite. Barytes. Fluor. ,, Cassiterite. ,, Pyrites. Chalcopyrite. Limonite. Goethite. Wolfram. ,, Cuprite. Copper. Galena. Blende. ,, Bournonite, &c. Chlorite. Mispickel. Pyrites, &c. Fluor. Galena. Blende. Chalybite. Dolomite, &c. Pyrites. Chalcopyrite. ,, Blende, &c. Fluor. Mispickel. Limonite, &c. CASSITERITE CHALCOPYRITE GALENA PYRITES 72 CHAPTER VI. PABAGENETIC. CUPRITE is commonly associated with Copper. Malachite. FLUOR SERPENTINE Besides the above, many notices of in the alphabetical part of the work. Chessylite, &c. Wolfram. Chlorite. Orthoclase. Chalybite, &c. Steatite. Diallage. Asbestos. Chrysocolla, &c, associated groups of minerals will be found A HAND-BOOK TO THE MINEKALOGY OF CORNWALL AND DEVON. PART II. A. AGNESITE. Accretion. Increase by external addi- tions of new matter ; applied only to inorganic substances. Acicular. Needle-like. Long, slender, and straight prisms are termed acicular. Acicular Arseniate of Copper. See Olivenite. Acid. A substance containing Hydro- gen, which is displaceable by a metal a salt being formed. In some instances it is necessary that the metal be presented in the form of an hydrate. The acids are Hydrogen salts. They have a sour taste, and turn blue litmus paper red. Adamantine. Diamond-like. A term applied to the lustre of some minerals. Actinolite. See Amphibole. Adherent. A term applied to a few minerals which absorb moisture so ra- pidly as to adhere to the moist tongue. Ex. Lithomarge. Adularia. See Orthoclase. A GA LMA TO LITE. [Figure stone. Pagodite.] Amorphous, massive, compact ; sectile, but easily broken ; fracture splintery or flat con- choidal ; opaque to translucent on thin edges; dull; various shades of red, green, yellow, grey, and brown ; unc- tuous; streak white; H. 2-3; G. 2 '4-2 '9. ', etc. In matrass gives off water; on C alone turns white ; Fus. 5-6, the white residue treated with Co turns blue ; with borax forms a colourless bead ; in- soluble in HC1 or HNO 3 ; the powder is decomposed by warm H 2 SO 4 . < Comp. It is essentially an hydrated silicate of alumina and potash. No analysis of a British specimen is known to the writer, but in four Chinese spe- cimens the silica ranged from 64 50 to 56 '0 per cent., alumina from29'0to34'0, peroxide of iron 0'5 to 1*25 ; lime to 2-0, potash 5'25 to 7'0, water 3'0 to 5'0. With silica 54 '2, alumina 31 '0, potash 9 '4, and water 5 '4, the formula may be written K 2 3Al 2 9Si3H2 (when the oxygen ratio will be as given by Dana 1 : 9 : 18 : 3) or Si 9 O 9 Ko 2 (Al 2 o") 3 Ho 3 . Loc. Restormel Koyal Iron Mines, Lostwithiel, nearly white, or of a flesh red tint. Also Wales, Ireland, Norway, Germany, China, &c. 06s\ Agalmatolite is often much like Steatite and Lithomarge, but it is harder than Lithomarge and less lustrous ; and differs from Steatite in the absence of magnesia and the presence of potash. The reaction with "Co" will distinguish between Steatite and Agalmatolite, as Steatite turns red, while Agalmatolite turns blue. (See Blowpipe Keactions.) Dana considers Agalmatolite to be a variety of PinLe. The Kestormel mineral has been named Agalmatolite from its external characters alone. Agate. Agate Jasper. See Calcedony. Aggregate. A confused crystalline AGNESITE. Amorphous; massive, disseminate, in- vesting; or in pseudomorphous acicular crystals ; brittle ; fracture conchoidal ; opaque to translucent on thin edges ; lus- tre vitreous, glimmering, or dull; various shades of green or yellow ; streak white or greenish-white ; H. 4-4 '5; G. 6 '9-7. ., etc. In matrass gives off a little water, decrepitates, turns grey ; on O alone melts easily, boils, and is reduced to a grey brittle metallic bead, depositing a dark yellow coating on the charcdal; soluble with effervescence in HJNO 3 ; the ALBITE. ALLOPHANE. solution turns white on addition of a large quantity of water. Comp. It appears to be an impure carbonate of bismuth, if the following analysis of a specimen from St. Agnes by Mr. Gregor be reliable : Carbonic anhydride 51 - 3 Sesquioxide of bismuth 28 '8 Oxide of iron 21 Alumina 7'5 Silica 67 Water 3'6 Total 100-0 Thomson states (Min. II. , 594) that it "does not elf ervesce with acids, and con- tains only a trace of Bi." It may, perhaps, be only an impure bismuth ochre. The author has not been able to procure a specimen for examination. Loc. St. Agnes, at Huel Coates. A similar mineral is said to have been found at Botallack. It occurs also in Germany. Alabaster. See Gypsum. ALBITE. [Soda Felspar.] Anorthic; with two perfect cleavages, basal (O) and brachy- diagonal (M), figs. 174, 175, and 182, form- ing angles of 93 36' and 86 24'; in variously modified prisms ; very often macled ; also massive, lamellar, or com- pact (Felsite); brittle; fracture uneven ; transparent to opaque ; vi treous or pearly ; white, sometimes tinged with yellow, red, green, blue, grey; some specimens shew a bluish opalescence, or a play of colours on the basal cleavage. Streak white ; H. 6-7; G. 2 "6-2 7. Vir. Cleavelandite is a lamellar white albite. Pericline occurs in large opaque white crystals, which are often short and broad. Compact albite or albitic Felsite, usually contains disse- minated grains of silica. B., etc. In matrass unchanged ; on C alone fuses at 4 to a colourless or white glass, turning the flame intensely yellow. It is not acted upon by HOI, HNO 3 , or HS 804. Comp. Albite is an anhydrous silicate of alumina and soda, containing an ex- cess of silica. The soda is often partially replaced by potash and other bases. The following is a recent analysis of a speci- men from Trewavas, in Breage, by the Kev. S. Haughton ; Silica 65-76 Alumina 21 72 Lime 0'89 Magnesia trace Soda 9 23 Potash 176 Water 0'40 Total. The range of composition in specimens from other localities is considerable. The silica varies from 65 "4 to 70 '0; alumina 181 to 21'9; oxide of iron to 2 '3 ; lime to 37 ; magnesia to 1*5 ; soda 6'2 to 12'2 ; potash to 6 '8. With silica 68 '6, alumina 19 '6, and soda 11 '8, the formula may be written AUNaSi (oxygen ratio =1 :3 :12), or Si 6 O 8 Nao 2 Al 2 ovi. Loc. Huel Friendship, Camelford, on quartz ; Tintagel cliffs ; Delabole slate quarries, in white crystals like Fig. 182, with scheifer spar and quartz ; Tre- wavas Head, Breage; and other localities in the two counties. An interesting specimen of albite, in very peculiar colourless transparent twinned crystals, was recently found at Huel Metal, in Breage. in the 135 fathom level, by Capt. G. M. Henty. It is now in the British Museum. Obs. The Eev. S. Haughton ob- serves : -" The granites of Cornwall and Devon, which have been frequently ex- amined by me during the last sixteen years, appear all to contain the two felspars albite and orthoclase." The presence of albite is thought to be an indication of the eruptive origin of the granites in which it occurs. It is most readily distinguished from orthoclase by the inclination of its cleavages and the intense yellow tinge which it imparts the blowpipe flame. It is also more fus ble than orthoclase, fusing at from 3 to Angles. MO = 93 36' My = 149 12> MT 117 53 Og 29 55 O T 115 05 Ox 52 37 M f 148 30 y o 152 18 Mo 67 49 ox 152 41 OO 173 28 Alkaline. Having the properties an alkali. The alkalies, potash, sod ammonia, and lithia have an acric caustic taste, and will turn yellow tu meric paper brown, and reddened litmu paper blue. Lime, baryta, strontia, an magnesia possess the same properties i a less marked degree, and are terme alkaline earths. Alliaceous. An odour resembling tha of garlic (allium), which is given o when minerals containing arsenic ar heated on charcoal. Some give off th odour on being broken. ALLOPHANE. Amorphous; mammillary, stalactitic incrusting, or occasionally pulverulent brittle ; fracture imperfect conchoidal o earthy ; translucent to opaque; vitreou*j ALLOY. AMPHIBOLE. resinous, or waxy ; shining or dull ; pale sky blue ; sometimes colourless, or grey, green, red, yellow, or brown ; streak white; H. 3; G. I'S-IU B. , etc. In matrass yields much water ; on C alone crumbles to a white infusible powder, which turns blue when treated with Co ; decomposed by HC1, gelatinous silica being deposited. Cornp. It is an hydrous silicate of alumina. No complete analysis of a spe- cimen from the West of England is pub- lished, but the composition generally ranges from silica 17*0 to 241, alumina 29-2 to 41-0, lime to T9, water 35 '2 to 44'2. With silica 221, alumina 38 '0, and water 39 '9, the formula may be written Al 2 Si6H 2 (oxygen ratio = 3:2:6) LOG. Garras Mine, near Truro, in greyish translucent reniform masses, very brittle. There is a fine specimen from this locality in the Museum of the Royal Institution of Cornwall at Truro, and another in the Museum of Practical Geology, Jermyn-street, London. Tavis- tock (near) in beautiful pearly and trans- lucent masses, some tinged blue or green, with a little copper. Also Kent, France, Belgium, Germany, United States, &c. Obs. Schrotterite is, perhaps, only a variety with less silica. Dana (System of Min., 421, 1868) gives "Cornwall" as a locality for schrotterite, but does not say in what part. He may refer to the mineral found at Garras Mine. The composition of schrotterite ranges from silica 10 '5 to 12 '0, alumina 46 '0, peroxide of iron to 2 '95, water 35 "5, to 41 '0, which is nearly equal to 8Al 2 3Si3H 2 . Alloy. A combination of two or more metals. "When mercury is one the alloy is termed an amalgam. Almandite. Almandine. See Garnet. Alum. A name for a group of minerals having a great similarity of composition and properties ; all are very soluble, all have more or less of the astringent taste of common alum (Kaliuite); all are cubi- cal ; sulphates ; and contain 24 equiva- lents of water of crystallization; all have the ratio of base and acid, and protoxide to peroxide = 1:3. Alum. See Kalinite. ^ Alumina is the sesquioxide of alumi- nium, and is represented by the formula AlgOs. In its pure state it is a white powder, and when crystallized forms the mineral corundum, which includes the ruby, the sapphire, and emery. Many minerals which contain alumina, if pow- dered, heated on charcoal in OF, moist- ened with a solution of nitrate of cobalt (Co), and again heated, turn to a bright blue colour. This reaction is successful only in the absence of the oxides of iron, manganese, and other heavy metals. If after heating on charcoal without fluxes there remains a white, or nearly white, infusible mass, the experiment is likely to be successful. Amalgam. See Alloy. Amethyst. See Quartz. Amianthus. See Amphibole. Amorphous. Without form. A term applied to minerals which are not known to crystallize. AMPHIBOLE. [Hornblende; &c.] Oblique, in prisms, usually modified, often macled, the faces often curved, or striated, or uneven ; cleavage perfect, prismatic ; parallel to M. (Fig. 181); the angles formed by the cleavages are 124 30' and 55 30' ; in ag- gregates of long thin prisms ; or massive, nbrous, divergent, reticulate ; granular, disseminate, or compact ; tough, brittle, or flexible ; fracture imperfect conchoi- dal, uneven, or splintery ; translucent to opaque ; vitreous, pearly, glimmering, or dull ; sometimes white, but more usu- ally green, of various shades; or grey, yellow, brown, or black; streak white or slightly brownish ; H. 5 to 6 (except asbestos and amianthus, which are soft): G. 2-9-3-4. Var. 1. Hornblende. Short thick prisms, or massive ; usually dark green or almost black ; tough. 2. Actinolite, long prismatic aggre- gates, often divergent or radiate; brit- tle ; usually some dark shade of green. 3. Tremolite, white, grey, or light green bladed crystals, with a pearly lustre, containing much MgO and CaO, and some FeO, with but little A1 2 O 3 . 4. Asbestos, Amianthus, &c. Gener- ally white, and in fine soft flexible fibres, that are easily separated. 5. Mountain Paper, Mountain Cork, Mountain Wood, &c., in brown felted masses, that will sometimes float on water until finely powdered. 6. Amphibolyte or hornblende rock is massive, dark green or black, with a granular texture. Hornblende schist is similar, but has a slaty structure. Both often contain some albite. J?., etc. In matrass usually unchanged, but sometimes yields a little water ; on C alone fuses at from 3 to 4, according to the amount of iron present, to a grey, green, or black bead, the darker ones mostly magnetic; with soda forms a fusible slag; with borax or micro. AMPHIBOLE. AMPHIBOLE. generally gives Fe reactions: insoluble in HC1 or HNO 3 . Comp. Tremolite is a silicate of mag- nesia and lime ; actinolite and asbestos of magnesia, iron, and lime ; hornblende of alumina, magnesia, iron, and lime. Of the following analyses a. is a " tremo- 1:t ~" from Clicker Tor, analysed by the from Huel Unity, analysed by Thomson, in which the iron is partly replaced by manganese: sp. gr. 2'91 (Ann. Phil. 1814):- a. b. Silica 62-2 33-40 Alumina 28-20 Oxide of iron 5'9 Oxide of manganese . . trace Lime 14-1 Magnesia 12-9 Soda trace Oxide of copper Water 1-0 Loss 3-9 1715 7'20 1-05 3-80 1-03 1-70 5-90 Loc. 1. Hornblende Botallack, Cape Cornwall, and many other parts of St. Just ; Marazion Mines, Acton Castle, Cuddan Point, and many parts of the Mount's Bay coast ; Goonhilly Downs, Mullion, Kynance, Coverack, Cadgwith, and other paits of the Lizard district ; West Godolphin Mine, Breage : West Rev. Wm. Gregor (Ann. Phil., 2, 1813, Poldice Mine, St. Ives ; Great Dowgas p. 154); b. is an "asbestos actinolite" i Mine, St. Stephens; Camborne Vean Dolcoath, Huel Crofty, and other Cam- borne mines; Tresavean Mine; Penmare Point, Veryan ; Five Lanes, Launceston. Hay Tor, Brent Tor, Bovey Tracey, and other places in Devon ; but seldom in well-formed crystals. 2. Actinolite At most of the above localities, and at North Roskear Mine, Camborne ; in greenstone, between East Huel Crofty and Pool ; Trevascus Mine ; St. Ives Consols, Huel Unity, Gwinear; the Consolidated Mines, Gwennap, at 320 fathoms from surface ; Charlestown United Mines and Duforth Mine, St. Austell; Great Retallack Mine Perran- zabuloe ; Maudlin Mines ; St. Cleer ; Cheesewring and Clickor Tor, near Lis- keard ; Delabole Slate Quarries, in dark green foliated masses ; Fowey Consols, in quartz. Seaton, Sticklepath, near Okehamp- ton, &c. 3. Tremolite St. Just, Lizard, and St. Cleer ; in the abovementioned localities; and at East Huel Crofty. 4. Asbestos, Amianthus, Mountain Wood, Mountain Paper, Mountain Lea- ther, &c. At most of the above localities ; at St. Veep, of a dull white colour ; and at Axmouth, Seaton, and Sidmouth, in Devon. Foreign localities of all the varieties are very numerous. Ob*. Many of the "greenstones" of the^West of Cornwall, especially about Gwinear and Marazion, cousist of nearly pure hornblende, or of hornblende inti- mately mixed with felspar. Some of them Total 100-0 100-00 The range of composition in foreign varieties is very great. In Actinolite, Asbestos, &c., the silica ranges from 55 '0 to 60'0 per cent., alumina to 3 '2; oxide of iron 3'0 to 12 '0, oxide of manganese to 1-2 ; magnesia 9'5 to 24*0, lime 9*5 to 21 '0, water to 3 '6. In Tremolite, silica 57 '3 to 60'6, alumina to 1 8, oxide of iron to 2 '4, magnesia 24'0 to 28 2, lime ll'O to 151, water to 3 '3. Hornblende, silica 37 '0 to 55 '0, alumina 4 "5 to 17 '6 peroxide of iron to 10 '2, protoxide of iron 5'8 to 29'3, oxide of manganese Oto 3'5, magnesia 5'0 to 21 '0, lime 4 '6 to 15-0, water Oto 2U With silica 57 '6, magnesia 28*8, lime 13 '6, the formula for Tremolite may be Ca 3Mg 4Si (oxygen ratio for bases and silica 1 to 2) or Si 4 O 4 Mgo" 3 Cao". With silica 53 '6, magnesia 18 '0, oxide of iron 16 '0, lime 12 '5, the formula for Actinolite may be CaFe2Mg4Si (oxygen ratio = 1 to 2) or Si 4 O 4 Mgo" 2 Feo"Cao". With silica 531 alumina 11 '3, oxide of iron 15 '9, magnesia 13*2, lime 6 '5, the formula for Hornblende may be Ca2Fe3MgAl 2 8Si (oxygen ratio for prot- oxides, peroxides, and silica = 6 : 3 : 16) or Si 8 O 7 Al 2 o vi Mgo" 3 Feo" 2 Cao". 06s. Tremolite usually occurs asso- ciated with limestones, particularly those that contain magnesia. Actinolite is associated sometimes with steatite ; the asbestiform variety with serpentine ; Hornblende with mica schist, chlorite chist, and gneiss. contain minute grains of magnetite dis- seminated through them, which, if the rock be finely powdered, may be separated by the magnet. Like most of the ferrugi- nous hornblendes, they are very liable to decomposition, thus forming some of the richest soils of the county. Amphibole and Pyroxene are very closely-related species, if, indeed, they should not rather be viewed as one. Dana remarks that "it is impossible to distinguish them by blowpipe characters alone." The range of chemical composi- tion is so great as to render a chemical division in the highest degree artificial Crystals of amphiboleand pyroxene differ AMYGDALOID. ANATASE. strikingly in habit and in modifications, but it is quite possible to refer all these modifications to the same system of axes. Twins have been found composed part of amphibole and part of pyroxene. The sp. gr. of hornblende is, however, usually a little less than that of pyroxene, and hornblende mostly occurs in. rocks con- taining quartz or free silica, and ortho- clase or albite, while pyroxene occurs in rocks containing little or no free silica, and with such minerals as labradorite, olivine, and leucite. It seems not unlikelv that hypersthene also might be included in one species with amphibole and pyroxene. Hypersthene is sometimes made to include bronzite, but Dana includes some infusible bron- zites with amphibole, and the fusible varieties with augite. Much of the so-called asbestos is chry- sotile, or fibrous serpentine. It may be distinguished from the true asbestos by giving off a large quantity (12 to 14 per cent.) of water, on heating in a matrass. Angles. M M' = 124 30' b r = 105 46' MO 103 12 rr' 148 oO Mb 117 45 Amygdaloid. A rock of a vesicular structure, the cavities being occupied with different materials. When these are light coloured, as is usually the case, and the rock is dark, the whole presents an appearance something like almonds in a cake. Hence the name, from a Greek word signifying an almond. Such rocks are common in the Hebrides, the Giant's Causeway, and in many vol- canic regions. Many of them seem to have been originally vesicular lavas, through which water charged with cal- careous and siliceous matter has perco- lated, and gradually filled up the cavities with agates, spars, zeolites, &c. Some of the cliffs near the Botallack Mine exhi- bit an imperfect amygdaloidal structure. ANAL CITE. [Analcime. Kubizite.] Cubical, usually in deltohedrons, like Fig. 5, but some- times a combination of the cube and deltohedron (Fig. 19); also massive, fibrous, or radiating ; brittle ; imperfect conchoidal or uneven fracture ; trans- parent to opaque ; vitreous or pearly ; white, or various shades of grey, green, yellow, red ; streak white , H. 5 to 5'5 ; G. 2 to 2 '3 ; feebly frictio-electric. B., etc. In matrass gives off water, and turns white ; on C alone turns white, and fuses at 2 '5 to a clear glass ; readily decomposed by HC1, depositing gela- tinous silica. Comp. Analcite is an hydrated silicate of alumina and soda. Its range of com- position is silica 51 '0 to 56 '2, alumina 22-2 to 24-2, lime to 5'8, soda 6'5 to 14 '6, potash to 4 '6, water 7 '6 to 97. With silica 54 '6, alumina 23 '3, soda 141, water 8 '2, the formula may be written Na 2 Al 2 4SiH2 (oxygen ratio for protoxides, peroxides, silica, and water 1 : 3 : 8 : 2, or, counting the water basic 3:3:8), or Loc. It is said to have been found in cavities of the cliffs near Botallack, but the author has never seen a Cornish specimen ; the mention of it may, how- ever, lead to its discovery in this nofc unlikely locality. It is found in Scot- laud, Ireland, Faroe, Iceland, Norway, Germany, Italy, United States, &c. Obs. Analcite is usually found in amygdaloids, or in rocks of volcanic origin, in forms resembling Figs. 5 and 19. Angles. a a = 90 00' nn = 146 27 an 144 44 n n' 131 49 Analysis. The separation of the con- stituent parts of a compound. The statement of the result of the process is often spoken of as the analysis. The person by whom the work is done is called the analyst. ANATASE. [Octahedrite.] Pyramidal ; in small crystals, like Figs. 72, 73, and 234, with perfect cleavages parallel to P. and O. from P. to P. = 97 51', P. to O. = 111 42' ; brittle ; sub- conchoidal or un- even fracture ; semitransparent to opaque ; lustre adamantine or sub metal- lic, usually brilliant ; brown to deep blue by reflected light, greenish-yellow by transmitted light ; streak white or slight- ly coloured; H. 5 '5-6 ; G. 3 "8-4, after heating 41 to 416; frictio-electric. B., etc. In matrass unchanged or phosphorescent ; on C infusible ; with soda melts to a dull yellow globule, white on cooling; with micro. OF forms a clear bead, which is yellow while hot, violet when cold ; if iron is present the bead may be brownish, but will be ren- dered violet by the addition of a small fragment of tinfoil; soluble in concen- trated H 2 SO 4 , but not in HC1 or HNO 3 . Comp. Titanic anhydride. Ti or TiO a ; Oxygen 7971, Titanium 60 '29. Lor. Looe Mills Hill Quarry, near Liskeard; Tintagel Cliffs; Delabole Slate Quarries ; Virtuous Lady Mine, in chlo- rite, in crystals, like Figs. 72 and 73, which vary in size from one-sixth of an inch downwards to microscopic crystals. ANDALUSITE. ANNABEEGITE. Angles. P P = 97 51' e e = 116 43' PP' 136 30 ee' 121 16 PO 111 42 11 159 26 Ov 160 15 cl 139 50 ANDALUSITE. [Chiastolite. Made.] Rhombic. Usually in four-sided prisms, like Figs. 94, and 95 ; also massive, with a lamellar structure ; tough ; fracture even or un- even ; translucent to opaque ; lustre vitreous or pearly, but often dull ; white, or tinged with violet, grey, red, green, brown; streak white; H. 7-7 '5, ex- cept when partially decomposed, when it may be as low as 3 ; G. 2 9-3 '4. Var. Chiastolite is a variety occur- ring in square prisms, which appear to be made up each of four crystals, having prisms of a darker colour in the centre and at each angle, connected by thin plates of the same, like Fig. 94. The colour of the dark portion may often be destroyed by heating. B., etc. In matrass unchanged ; on C inf us/ble ; the powder moistened with Co and again heated becomes blue ; with borax fuses with difficulty to a trans- parent colourless glass ; with soda swells up, but does not fuse ; insoluble in acids, but some varieties are decomposed by HC1, leaving a mass of gelatinous silica. Comp. Anhydrous silicate of alumina, but usually contains some peroxide of Fe and oxides of Mn, Mg, and Ca. The fol- lowing range of composition has been indicated by various analyses of foreign specimens, viz.: Silica 33'0to4017; alumina 50 '96 to 62 '20 ; peroxide of iron to 5 71 ; oxide of manganese to 0'83 ; magnesia to 114; lime to 412; water to 2 '6. With silica 36 '8, and alumina 63 '2, its formula might be AL>Si (in which case the oxygen ratio = 3 f 2) or SiO(Al 2 4 )". LOG. "Andalusite, in attached and imbedded crystals, is said to occur on Dartmoor, and also in the neighbourhood of Okehampton. Chiastolite is found in small crystals penetrating an altered Devonian slate at Ivybridge, and also associated with axinite at Holestock, near Okehampton." (Report of Devon Assoc. 1868, p. 341.) Also Cumberland, Scotland, Ireland, Brittany, Spain, United States, &c. Obs. Chiastolite may be distinguished from felspar by the black cross seen in the cross section of the crystal; andalu- site by its superior hardness and ex- treme infusibility. The surfaces of the crystals are often rough, or covered with flakes of mica. In some instances the whole crystal has been converted into mica. Angles. M M = 90 44' M O = 90 QV O s 144 55 Angle. See Crystallography. ANGLESITE. Rhombic, often in tabular or prismatic j crystals, like Figs. 127, 128, 129, 130, : 132, with cleavages parallel to M. and ; O., but not perfect ; or drusy ; also sta- | lactitic or massive ; brittle ; fracture i conchoidal ; transparent, to translucent i on edges only ; adamantine, vitreous, or | resinous ; white, sometimes tinged grey, j yellow, green, blue, brown; sometimes i black on the surface ; streak white ; H. 3 ; G. 61-6-4. B., etc. In matrass decrepitates and i darkens ; often yields a little water with acid reaction ; on C fuses at I'o to a ' globule which is clear while hot, but milk ! white on cooling ; in RF is easily reduced I to a bead of Pb ; with soda and silica gives i the reaction for sulphur ; almost insolu- | ble in acids, but the powder is com- pletely soluble in KHO. Comp. Sulphate of lead, PbS, or PbSO 4 , or SO ;2 Pbo".; oxide of lead 73'61 ; sulphuric anhydride 26 '39. LOG. Mellanoweth, near Hayle; for- merly in gossan at Huel Maggot ; Huel Bell, St. Erth; Huel Rose and Huel Penrose, near Helston ; West Huel Chi- verton ; Pendogget, Liskeard ; Beeral- stone ; East Tamar Mine ; Beerferris, in geodes of decomposed galena, the faces M. and z. predominating. Fig. 132 is a Cornish form. Also Cumberland, Derby- shire^ Anglesea, Scotland, Germany, Siberia, United States, &c. Obs. Anglesite usually occurs with galena, pyromorphite, cerussite, and other ores of lead. It is not a common mineral in the West of England. Angles. O M = 90 W d d' 78 45' Ob 90 00 zz' 89 41 MM' 103 38 oo' 75 39 Oo 127 45 LI 135 20 Od 140 38 dd 101 15 Anhydrous. Without water. Minerals which do not yield water, even when strongly heated, in a closed tube before the blowpipe, are said to be anhydrous. Anhydrous Binoxide of Manganese. See Pyrolusite. ANNABERGITE. [Nickel green. Nickel ochre.] Oblique ; in minute capillary crystals, as a flaky efflorescence ; massive ; disseminated j friable or sectile ; dull or glimmering ; va- rious shades of green ; streak light green ANOKTHIC. ANTIMONY. or white, shining; H. 2-2'5; G. 3-3'2. U., etc. In matrass yields water and darkens ; on C melts readily, giving off fumes with a strong garlic odour, and coating the charcoal white at a little dis- tance from the assay ; in RF yields a white brittle bead of metallic appear- ance ; with borax OF a bead which is often violet while warm, and reddish- brown when cold ; RF the bead becomes colourless or greyish ; soluble in HC1 or HNO 3 , forming a green solution. Comp. It is an hydrous arseniate of nickel. No analysis of a British speci- men is known to the author. The aver- age composition of foreign specimens analysed approaches to arsenic anhy- dride 38'6, oxide of nickel 37 '2, water 24 '2, which would agree with the follow- ing formula : 3NiAs 2 + 8H 3 or As 2 O 2 Nio" 3 + 8OH 2 . Lac. Pengelley Mine and Huel Chance, Si. Ewe; St. Austell Consols; Huel Jane, St Kea, on kupfernickel (Nicco- lite). Also France, Germany, Canada, United States, &c. Obs. From its occurrence on the sur- face of other nickel ores containing arsenic, it is probably a product of their decomposition. Anorthic. See Crystallography. Anthracite. See Coal. Antimonial Ochre. See Cervantite and Stibiconite. Antimonial Silver Blende. See Py- rargyrite. Antimonial Sulphide of Iron. See Berthierite. Antimoniate of Lead. See Bleinierite. ANTIMONITE. [Antimony Glance.] Rhombic ; Fig. 97; usually in laterally aggregated prisms, with one perfect (brachydiagonal) cleavage; which truncates MM'; diver- gent or radiating ; the cleavage planes often striated ; also massive, with colum- nar structure ; or fibrous, plumose, woolly, or felt-like ; sometimes dissemi- nated, brittle, or sectile ; thin laminaa slightly flexible and malleable ; fracture sub-conchoiual, but rarely obtained; opaque ; metallic ; steel-grey to lead- grey ; streak black ; H. 2 ; G. 4 '5-4 7. B . etc. In matrass gives a yellow or reddish sublimate but no water ; on C fuses at 1, and burns with a greenish flame, depositing a white coating near the assay; entirely volatile, except some- times a very little infusible slag, which gives Fe reactions ; soluble in warm HC1, giving off H 2 S ; decomposed by HNOs, leaving a white powder of oxide of anti- mony; decomposed by KHO, the solu- tion yielding a yellowish flaky ppt. on adding HC1. Comp. Anhydrous sulphide of anti- mony. a. b. Sulphur 74-0 74'06 Antimony 26'0 25'94 Total lOO'O 100-00 a. by Bergmann, b. by Davy. Both spe- cimens Cornish. "With 72 "88 per cent, of antimony and 27'12 of sulphur the formula will be Sb 2 S 3 . LOG. Huel Boys, Endellion (Fig. 97), and plumose ; Padstow and Tintagel, in N. and S. veins, in fibrous masses ; Old Trewetha ; Pendogget and Port Isaac (plumose), St. Merryn ; Huel Lee, St. Minver ; Pillaton, St. Stephens ; Fowey Consols ; Restronguet, near Devoran ; Hennock ; Bovey Tracey ; Combemartin, in small quantities, with argentiferous galena, both fibrous and in acicular crys- tals. Also Cumberland, Scotland, France, Spain, Germany, Hungary, Italy, Borneo, N. America, S. America, &c. Obs. It is the chief ore of antimony. It may be distinguished from jameso- nite, which it often much resembles, by the absence of a basal cleavage, and its almost complete solubility in HC1 ; from pyrolusite, graphite, and molybdenite, by its fusibility. It is isomorphous with bismuthite. A ngles. M M' = 89 15' M M = 90 45' Mb 134 37 p'p 109 16 Mp 145 29 pb 125 22 ANTIMONY. Hexagonal, sometimes in rhombohe- drons, with perfect basal cleavage, like Fig. 221 ; sometimes striated, usually reniform, spherical, or massive; lamellar or granular ; brittle ; opaque ; metallic ; tin-white, with a greyish tarnish ; streak like the colour; H. 3-3 '5; G. 6 '6-6 '8. /?., etc. In matrass melts and gives a slight white sublimate when strongly heated ; on C fuses readily and burns with a greenish flame, depositing a white coating on the charcoal near the assay, which tinges the flame greenish if directed upon it ; sometimes a slight garlic odour ; a melted bead crystallizes on cooling ; may be entirely volatilized, except a very little infusible slag, which will give iron reactions ; soluble in Aqua Reg^a. Comp. Antimony, with usually a little iron, arsenic, silver, or other im- purity. No analysis of a Cornish speci- men is on record. Loc. It is said to have been found in ANTIMONY. APATITE. the antimony mines near Padstow ; also France, Germany, Sweden, Borneo, Canada, United States Mexico, Chili, &c. Antimony. All minerals containing antimony when heated on charcoal de- posit a white coating on the cool part of the support, no garlic odour being ob- servable unless arsenic be present, which, however, is often the case. When lead, bismuth, cadmium, zinc, or silver are pre- sent the coating is liable to be obscured. In such cases there are no simple and generally applicable blowpipe tests. Antimony Glance. See Antimonite. APATITE. Hexagonal ; in six-sided prisms ; often vertically striated and variously modi- fied, like Figs. 189, 190, 191, 196 ; also massive, earthy, or fibrous ; brittle ; fracture conchoidal, uneven, or splin- tery ; transparent to opaque ; vitreous or resinous ; brilliant to dull ; white, or various shades of yellow, blue, green, brown, red ; sometimes parti-coloured or dichroic ; some crystals show a bluish opalescence when viewed in the direction of the principal axis ; streak white ; H. 4 '5-5; G. 3 "Z-3 '3; sometimes pyro or frictio-phosphoric. Var. Francolite is a name which has been given to specimens occurring in small compound crystalline masses, sometimes greyish, greenish, or brown- ish ; in minute white transparent crys- tals with Curved faces, somewhat like Fig. 189, but with deep and uneven longitudinal striations ; in thin plates with quartz and chalcopyrite, and in thin, hollow, pseudomorphous cubes of an inch or more, which, when first dis- covered arehalf f ullof atransparentfluid. B. t etc,. In matrass unchanged ; if mixed with micro, usually gives off HF ; on C fuses at 4-4*5 some varieties infusi- ble ; with borax melts to a clear globule, which may be rendered opaque by " flaming;" soluble very freely in micro., affording a glass which is usually trans- parent while hot, but if saturated, opaque and crystalline on cooling ; the powder moistened with H 2 SO 4 and heated tinges the flame bluish-green ; soluble in HC1 or HNO 3 without effer- vescence ; when warmed with HgSO^gives off a gas (HF) which turns Brazil wood paper yellow if fluorine be present. Comp. It is a phosphate of calcium, usually containing fluorine and chlorine. The variety called francolite contains only a trace of chlorine, as appears from the accompanying analyses. Foreign varieties of apatite contain from to 41 per cent, of chlorine, and from to 4 '2 per cent, of fluorine. Analyses ; both by T. H. Henry, from Huel Franco (Francolite): a. b. Phosphoric anhydride 41 '34 41 '80 Lime 53'38 52'81 Fluorine and loss 2'32 217 Chlorine trace trace Oxides of iron and Manganese 2'96 3'22 Total ............... 100-00 100-00 With phosphoric anhydride 42 '2, lime 54 '0, and fluorine 3 '8, the formula for Fluorapatite (Francolite) may be written 9Ca3P 2 + CaF 2 or P.sOgCao'^CaFO. With phosphoric anhydride 40 9, lime 52 '3, and chlorine 6 '8, the formula for Chlor- apatite (Apatite) will be 9Ca3P 2 -i- CaClj or P 3 O 3 Cao" 4 CaClO. The composition of a specimen lately analysed by Professor Maskelyne and Dr. Flight agreed with the following formula, viz., 5([3Ca2PO 4 ]CaCo 3 ) -!- 2Ca F 2 ; or a fluorapatite, in which one part of the calcium phosphate is replaced by calcium carbonate. Its crystalline form differs somewhat from ordinary apatite. Loc. The rocks north of Botallack, in white or yellowish-green crystals, i with hornblende, axinite, magnetite, garnet, &c. ; Botallack Mine ; Huel Owles: St. Michael's Mount, like Fig. 196, with topaz, tourmaline, cassiterite, &c.; Godolphin Bridge Mine and Tre- mearne (with gilbertite), in brilliant and highly modified transparent bluish, greenish, or greyish crystals, in granite ; Huel Kind, St. Agnes, on quartz, in small greenish crystals, with calcite, some like Fig, 189 ; St. Kea ; Poldice, in hexagonal tables ; Stenna Gwynn, greyish-blue in gilbertite ; Fowey Consols and Huel Franco (Francolite) ; St. Stephens; Crinnis. Bovey Heathfield ; Chudleigh ; near Bo- vey Tracey, cream coloured, in a quarry, Figs. 189 and 191. These crystals were sometimes two inches long, associated with pure tourmaline. This locality is exhausted, but other specimens may, perhaps, be found in the neighbourhood. Also Cumberland, Norway, Germany, Italy, United States, Scotland, Ire- land. Obs. Apatite is usually found in crystalline or schistose rocks, associated with tin and iron ores or with serpentine. In Cornwall and Devon it mostly occurs in granite, with tourmaline, cassiterite, and gilbertite. ABAGONITE. ARSENIC. A ngles. ab r o io 120 150 90 124 157 139 00' 00 00 20 05 47 z o X X r r u a r a u o 120 142 131 149 135 110 36' 20 14 38 39 03 Aqua Regia. A mixture of HC1 with HNC>3 ; so called because it will dis- solve gold the " King" of inetals. ARAGuNITE. Rhombic, usually in acicular crystals, or hexagonal prisms (macles), with one distinct and two indistinct cleavages, forming angles of 121 55', 116 10', and 125 47' ; also in globular concretions ; or reniform, dendritic, or coralloid ag- drusy and investing ; England, Scotland, Ireland, Spain, Ger- many, Hungary, Italy, United States, &c. Obs. Aragonite is a little harder and a little heavier than calcite, which has the same composition, its cleavages are less distinct, and do not produce rhom- bohedrons as do those of calcite ; it falls to pieces when heated in a matrass, in this also differing from calcite. Arborescent. Branched like a tree. "Dendritic" is sometimes used in the same sense. Native Silver is often arborescent. Arenaceous. Sandy. Argentiferous. Containing silver. ARGENT IT E. [ Yitreous Silver. Silver Glan ce. ] Cubic ; ia cubes, octahedrons, and rhombic do- decahedrons, or deltohedrons, more or gregations; or o , sometimes in fibrous or compact masses ; I less modified (Figs. 1,2,3,5,8, 19,20,&c.); brittle ; fracture conchoidal or uneven ; ! a l so reticulated, arborescent, stalactitic, transparent to opaque ; vitreous, resi- i amorphous, earthy, or disseminated ; nous on fracture, silky if fibrous; white, I sectile, often somewhat flexible or mal- or tinged with grey, yellow, red, blue, ' leable ; fracture hackly, uneven, or earthy ; opaque ; lustre metallic, often dull ; lead grey to black ; sometimes iridescent ; streak dark and shining : H. 2-2-5; G. 6 '9-7 '4. Var. Black sulphuret of silver, silver green, brown ; streak white, or much lighter than the colour; H. 3 '5-4; G. 2 7 to 3. Var. Flosferri is the name given to coralloid varieties, satin spar to a fibrous variety. B. , etc. In matrass swells and falls to powder, evolving a very little water ;' on C infusible, but incandesces and be- comes alkaline ; when Sr is present, mulm or silver black is an impure earthy variety. ., etc. In matrass gives a yellowish sublimate of S j on C fuses at 1, and is easily reduced to a white malleable bead which is often the case, the flame will of Ag, giving off a sulphurous odour ; be tinged carmine red, especially after j insoluble in HC1 ; readily soluble, ex- being moistened with HC1 ; if no Sr, cept a little sulphur, in hot concentrated then the flame will be brick red. Soluble with effervescence in dilute HC1 or HN0 3 . Comp. It is an anhydrous calcic car- bonate, but appears usually to contain a little Sr, Fe and H 2 O as impurities. With carbonic anhydride 43 '71, and lime 56 '29, the formula will be Ca C or COCao". LOG. It is said to occur at Botallack and Huel Owles in white, grey, red, or bluish-green globular concretions, or in- crustations, or druses, acicular and fibrous, on quaitz and chalybite. Many of these are certainly calcite. Huel Edward, with chrysocolla ; Levant, St. Erth, in fine macled hexagonal crystals, and in coralloid forms (flosferri); Huel Edward, Calstock ; Mawnan cliffs, near Fal mouth ; Port Isaac and Tintagel cliffs, coralloidal, white, greyish, or pinkish ; Buckfastleigh ; Combemartin (flosferri); Ilfracombe and Torbay, in beautiful acicular crystals and fibrous masses, in thin veins traversing slate ; also Cumberland and other parts of HNO> Comp. Anhydrous argentous sul- phide, as appears from the analyses of foreign specimens, which yield from 77 '6 to 85*3 per cent, of silver, with about 15 per cent, of sulphur, and usually some small proportion of Pb, Cu, and Fe. No analysis of a British specimen is published. With silver 87 '05, and sulphur 12 '95, the formula is Ag 2 S or SAg 2 . Loc. Huel Herland, in well-defined crystals (Figs. 8 and 15) and massive ; Huel Ann, Phiilack; Huel St. Vincent; Huel Brothers; Huel Duchy (earthy); Huel Mexico ; Huel Basset ; South Huel Basset ; North Dolcoath ; Dolcoath ; Mount Mine, Perranuthnoe, and some other mines in Cornwall, both massive and earthy. Also Scotland, France, Spain, Hungary, Italy, Germany, Nor- way, Siberia, Mexico, Peru, &c. A ngles. 00 = 109 a a 90 oa 125 dd 120 28' 00 16 00 n n n n' an ad = 146 27' 131 49 144 44 135 00 10 ARSENIC, ARSENOLITK Argillaceous. Clayey. Arragonite. Arragon Spar. Se Ara- gonite. ARSENIC. [Native Arsenic.] Hexagonal; some- times in rhombs with perfect basal cleav- age, like Fig. 221, but usually reniform, stalactitic, mammillary, or reticulate; also massive ; compact, with a curved amellar structure, granular, or dissemi- nated ; fracture uneven or fine granular ; opaque ; lustre metallic, often dull ; whitish, lead grey on fresh fracture, but usually a dark tarnish on the surface ; streak grey ; shining ; H. 3'5 ; G. 5 '9-6 ; when broken gives off an odour re- embling that of garlic. B., etc. In matrass a dark metallic ublimate when strongly heated ; in open tube a white crystalline sublimate ; on C volatilizes in dense white fumes with- out fusing, burning with a blue flame and strong alliaceous odour, and depositing a white coating on the cool part of the charcoal. It usually leaves a minute resi- due, which contains Fe, and sometimes Au, Ag, Co. Soluble in HC1. Comp. Arsenic, with generally small portions of other metals. No analysis of a British specimen is recorded, but foreign specimens yield from 96 to 99 per cent, of As. Loc. It is said to have been found at Dolcoath and Cook's Kitchen, with ores f tin and cobalt ; also Norway, Ger- many, France, Siberia, Chili, United States, &c. , generally in veins traversing altered slaty rocks. Obs. Arsenic may always be detected in a mineral by the white crystalline sublimate which is formed when the assay is heated in an open tube, and the odour resembling garlic which is evolved when it is heated on charcoal in R F. Arseniate. A compound of arsenic anhydride, with a metallic oxide ; or ar- senic acid in which the hydrogen has been replaced by a metal. Arsenic may be detected in arseniates, arsenides, or alloys, by the white incrustation depo- sited on charcoal far from the assay, and the strong alliaceous odour produced when this is treated with the reducing flame. The following arseniates occur in the two counties, each of which is described in its proper place : Olivenite, Pharmacosiderite, Liroconite, Pitticite, Clinoclase, Scorodite, Erinite, Annabergite, Cornwallite, Erythrite, Chenevixite, Bayldotdte, Ckalcophyllite, Mimetite. In many of these the arsenic is partially replaced by phosphorous. All are hydrous except mimetite. Arseniate of Cobalt. See Erythrine. Arseniate of Copper. See Olivenite, Clinoclase, Liroconite, Chalcophyllite, Cornwallite, Erinite, Chenevixite. Arseniate of Iron. See Pharmacosi- derite, Pitticite, and Scorodite. Arseniate of Lead. See Mimetite. Arsenic Bloom. Arsenic Oxide. See Arsenolite. Arsenic Silver. "A mixture of mia- plckel and discrasite, found formerly at North Dolcoath in masses with a con- centric lamellar structure, alternating with quartz, the whole bearing some re- semblance to agate." Arsenical Cobalt. See Smaltite and Cobaltite. Arsenical Iron. Arsenical Mundic. Arsenical Pyrites. See Mispickel. Arsenical Nickel. See Niccolite and Smaltite (Chloanthite). Arsenide. A compound of arsenic with some other metal or metals. Arse- nides differ from arseniates in the ab- sence of oxygen. They are much like sulphides in their physical properties. The arsenides found in the two counties are Niccolite, Smaltite, Cobaltite, Leu- copyrite (?). Miapickel is a sulpharsenide. ARSENOLITE. [Arsenious acid, Arsenious anhydride.] Cubical ; sometimes in octahedrons with octahedral cleavage, but usually capil- lary, flaky, pulverulent, stalactitic, bo- tryoidal, or investing ; brittle ; trans- lucent to opaque; vitreous, adamantine, silky, or pearly ; often dull ; white, or reddish, yellowish, brownish ; streak white; H. 1-1 '5; G. 3-6-37; taste sweet- ish and astringent ; highly poisonous. B., etc. In matrass altogether volatile, forming a white crystalline sublimate ; on C is partly reduced at first to a grey brittle metallic bead, which may be volatilized in dense white fumes by continuing th blast ; gives a strong alliaceous odour ; deposits a white coating at some distance from the assay ; slightly soluble in water, more so if the water be warmed ; soluble in HC1, the solution deposits a grey metallic coating on clean copper. Comp. Arseniousl anhydride. Asj O 3 ; it often contains a little sulphur. When pure its composition is Arsenic 7576, oxygen 24 '24. Loc. Huel Sparnon and some other mines, in acicular crystals, filling cavi- ties in smaltite ; sometimes investing smaltite and cobaltite. Also Germany, Transylvania, Spain, California, &o. ASBESTOS. AUTUNITE. 11 Asbestos. See Amphibole. ASBOLANE. [Earthy cobalt.] Amorphous; massive, earthy, pulverulent, or incrusting ; sec- tile, almost malleable ; opaque ; resinous, glimmering, or dull ; bluish and brown- ish-black ; streak black, shining ; H. '5 to 1'5; G. 2 to 2'2. B., etc. In matrass yields water; on C, infusible ; with micro gives a deep blue bead in both flames ; soluble in HNO 3 , yielding a pink solution. Comp. It appears to be a hydrated oxide of cobalt and manganese, but is very uncertain in its composition. No analysis of a British specimen is pub- lished, but two foreign specimens yielded 19 '45 of Co O and 35/47 of Co 2 O 3 respectively, there being in one case a larger and in the other as large a per- centage of oxide of manganese, together with 20 per cent, of water. It should, perhaps, be regarded as simply a cobaltio variety of "Wad. Loc. Eoscommon cliffs, St. Just ; Huel Unity, Huel Gorland, and other mines in Gwennap, in soft bluish-black masses ; also Cheshire, Scotland, Ire- land, Germany, &c. Asphaltum. See Bitumen. Assay. " A trial of the quality of minerals ;" a determination of the quan- tity of any element in a given com- pound ; also the portion of substance tried. Astringent. Anything having a taste which seems to dry up the juices of the palate and tongue is said to be astrin- gent. Ex. Alum and copperas. ATAOAMITE. Rhombic, with a perfect brachy- diagonal cleavage ; usually in aggregates of acicular prisms ; or renif orm, granular, massive, disseminated ; structure often curved lamellar and radiating ; brittle fracture conchoidal or uneven ; trans- lucent to opaque ; vitreous or silky colour various shades of green, mostly dark ; streak light green ; H. 3 to 3'5 G. 4 to 4'3 (Botallackite 3 '6). Var. Botallackite (Church) is, per- haps, a variety of atacamite, it occurs in minute interlacing crystals on killas ; it is vitreous, pale green, with a white treak. Tallingite may, perhaps, be another variety ; its colour is blue, anc it occurs in "thin crusts consisting o: irregular aggregations of minute globules which appear botryoidal under the micro cope." It is, however, described under its own name. B. , etc. In matrass gives off water with an acid reaction; with a strong heat greenish sublimate is deposited ; on C olours the flame bright blue ; with the R. F. it is easily reduced to a malleable >eadof Cu ; easily soluble in HClor HNO 3 with little or no effervescence ; readily oluble in ammonia, forming a deep blue olution. Comp. It is a hydrated oxychloride )f copper. The following analyses, by :*rofessor A. H. Church, of specimens rom Botallack, shew the composition >f a Cornish specimen of atacamite (a), and another of botallackite (b); the analysis of tallingite (c) and another mineral examined by Professor Church d) are subjoined for comparison : Oxide of a. b. c. d. copper.... 54-32 66 '25 53 "57 67 '25 Copper 13-57 1011 Chlorine ... 15 '20 14 '51 11 '33 8 '73 Water 16 '91 22 '60 24 '99 26 '56 Total 100-00 103-36 lOO'OO 102'54 a) agrees very well with the formula 3CuH 2 2 + CuCl 2 + H 2 0; (b) with 3CuH 2 O 2 + CuCla + 3H 2 O ; (c) with 4CuH 2 O 2 + CuCl 2 + 4H 2 O ; (d) with 6CuH 2 2 + CuCl 2 + 6H 2 0. Loc. B< >tallack, Atacamite in crusts and stalactitic tubes ; Botallackite in inter- lacing crystals, which are translucent under the microscope, and Tallingite as thin crusts of very small blue globular masses ; Atacamite occurs chiefly in Chili and Peru, but also in Germany, Africa, and South Australia ; it occurs also as a volcanic product at Vesuvius and Etna. Atacamite, Botallackite, and Tallingite may be distinguished from malachite by their little or no effervescence with HC1, and from all the other British ores of copper by their ready solubility in strong ammonia. Attle. Rubbish ; the refuse of a mine. Attle heap Mine burrow. Augite. See Pyroxene. Auriferous. Containing gold. Augitic. Containing Augite. AUTUNITE. [Uranite; Calcareous Uran mica.] rhombic ; but the brachy and macrodia- gonal nearly equal ; crystals, like Fig. 122, closely resembling those of Torbernite (Chalcolite) see Figs. 74 to 76 and 89; cleavage, basal, perfect ; sectile ; trans- lucent ; sub-adamantine, pearly on the cleavage ; greenish-yellow ; streak yel- low; H. 1-2-5; G. 3-3-2. B., etc. In matrass yields water and turns to a straw yellow ; on C fuses at 2 to a black mass with a semicrystalline sur- face ; with soda forms a yellow infusible slag ; soluble in HNO 3 , forming a yellow solution. 12 AXINITE. B. \BINGTONITE. Comp. No analysis of a Cornish spe- cimen has been published, but foreign specimens yield about 15 7 of phosphoric anhydride, 62 '7 of oxide of uranium, 6*1 of oxide of calcium, and 15 '5 of water. With these proportions the formula will be 2UVP2 + Ca + 8H 2 (oxygen ratio for protoxides, peroxides, phosphoric anhydride, and water = 1:6:5:8). Loc. South Huel Basset, in small bright yellow, nearly transparent, crys- tals ; Tolcarne, pale yellow inclining to green, at 30 fathoms depth ; Huel Ed- ward, St. Just; Gunnislake; Stenna Gwynn ; Lostwithiel. Also France, Ger- many, and the United States. Obs. Autunite was formerly thought to be isomorphous with Torbernite, and both were classed together as Uranite, but there seems reason to believe that they are distinct in form as they differ in composition. Autunite is said to be optically biaxial, that is, to have two axes of double refraction, which is the case withrhombic minerals, but not with those that are tetragonal. Autunite may be distinguished from Torbernite by its yellow streak; yellow solution in HNOg, and by not yielding a bead of Cu with soda before the blowpipe. Angles. MO- 90 00' M M = 90 00' nearly. 01 115 53 Ou 109 32 AXINITE. Doubly oblique ; usually in very oblique and unsymmetrical prisms, with rough or striated faces ; often so flat as to appear tabular, Figs. 184 to 187; sometimes massive, curved lamellar, or granular ; brittle ; fracture conchoidal or uneven ; transparent to translucent on thin edges ; vitreous and brilliant ; trichroic ; brownish, bluish, greyish ; streak white; H. 6 '5-7 ; G. 3 to 3 '3; frictio-electric, pyro-electric. ., etc. In matrass no change; on fuses at 2 with intumescence to a dark green magnetic glass, which in the O F turns black ; with borax or micro Fe and Mn reactions ; the powdered mineral fused with soda on platinum foil yields a green mass ; with fluor and monopotassic sulphate, boracic acid may be detected ; insoluble in H Cl until after fusion, when it is readily decomposed, leaving a jelly of silica. Comp. It is an anhydrous and very complex silicate and borate of alumina, iron, manganese, magnesia, and licue. No analysis of a British specimen is published, but foreign specimens contain quantities varying as follows : Silica 41'5 to 45'0 ; alumina 13 '5 to 19 '0 ; per- oxide of iron 7 '3 to 12 '3; manganic per- oxide 1'2 to 10 -0; lime 12 '5 to 25 '8; magnesia to 2'2 ; boric anhydride 2'0 to 5 '6. With silica 41 '1, alumina 16*3, peroxides of iron and manganese 15 '8, lime 21 '3, boric anhydride 4 '6, the for- mula may be written 12Ca 5A1 2 3Fe 3 2B 2 21Si (oxyqen ratio for protoxides, peroxides, boric anhydride, and silica = 2 : 4 : 1 : 7), or SiO 4 (2-7ths Ca. 4-7ths Fe. Al. l-7th B.) 2 . Loc. Rocks north of Botallack, Huel Cock, and Trewellard, in fine brilliant clove brown crystals, which have been obtained as much as 1| inch across, like Figs. 184 and 186, and forming a com- pact mass, with garnet, schorl, &c. ; Lamorna Cove, near Penzance ; Bos- cawen cliffs, St. Burian, light greyish- viol^t ; Carn Silver, Lamorran creek; Carharrack ; Camborne Vean ; Trevas- cus ; St. Columb ; Terrace-hill Quarry, Callington ; Lostwithiel ; Huel Friend- ship, near Okehampton ; Stickle path ; Brent Tor. Also Norway, Sweden, France, Spain, Italy, Germany, Russia, United States. Obs. Pseudomorphous crystals of chlorite of the exact form of the St. Just axinite have been found on Dart- moor and at St. Just. The Cornish crystals of axinite have the faces c. v. p. r. z. usually predominating ; the faces y. and c. are said to be peculiar to the St. Just crystals. Angles. PC = 113 PI 151 P z 116 96 134 146 135 102 119 130 151 15' 03' 26 32 48 39 25 30 50 28 30 lu r c ry r s r v r w r x U 8 vy xy cy 153 25' 85 40 85 143 93 114 139 152 139 126 35 38 14 30 12 01 09 25 If Ps Pu Pv Pw Px wy 151 30 cy 156 20 Axis. Axes are imaginary lines, cross- ing a crystal in its centre, to which its faces may be conveniently referred. See Crystallography. Azurite. See Chessylite. B. BABINGTONITE. Anorthic ; usually in small crystals, like Fig 235 ; two perfect cleavages, parallel to Oft. Also fibrous or radi- ating ; brittle, fracture imperfect or hackly ; thin splinters or laminae trans- BARYTES. BAYLDONITE 13 lucent ; vitreous ; blackish-green, or di- chroic, green, and brown ; streak white or greyish ; H. 5-5 '5 ; G. 3 '3-3 '5. B., etc. In matrass unaltered, or sometimes decrepitates ; occasionally a little water is evolved ; after heating it gives an alkaline reaction on test papers, on C fuses at 3 to a brilliant brownish- black globule, which is sometimes mag- netic ; with borax forms a clear reddish- yellow glass, nearly colourless on cool- ing ; in reducing flame becomes greenish ; with micro, the same reactions, but s skeleton of silica is left in the bead ; scarcely acted upon by acids ; with soda and nitrate of potash on platinum foil the manganese reaction is readily ob- tained. Comp. Anhydrous silicate of iron and lime. The following is a recent analysis of a specimen from Devonshire, by Pro- fessor Forbes, F.R.S.: Silica ........................ 4912 Alumina ..................... T60 Peroxide of iron ............ 978 Protoxide of iron ......... 12 '87 Oxide of manganese ...... 1*25 Lime .......................... 20'87 Magnesia ..................... 3'67 Loss on ignition ............ 0'73 99-89 this is nearly equal to 12Si Fe 2 3Fe 6Ca or 6CaOSiO 2 + 3FeOSiO 2 or Si 9 O 9 Feo" 3 Cao" 6 Si 3 O 3 Fe 2 OTi. Loc. In a railway cutting in Devon- shire ; also in the Shetland Isles, and in Norway. Obs. It is, in appearance, much like hornblende. The Devonshire mineral 'was discovered in 1854, and was so abundant as to be worked as an ore of iron. Angles. M t = 112 30' O t = 88 00' OM 92 34 hg 90 40 Baryta. The oxide of the metal Barium is so called. BARYTES. [Barite. Heavy spar.] Rhombic; in tabular or prismatic crystals, like Figa. 130 to 135, which are all Cornish forms ; single, aggregated, or drusy ; four dis- tinct cleavages ; M. and O. perfect, a. and t>. less perfect, the cleavages forming angles of 90 0', 78 20' , and 101 40' ; also in foliated, columnar, radiated, fibrous, granular, compact, earthy, or stalactitic masses ; sometimes a curved lamellar structure ; brittle ; fracture con- choidal, but not easily obtained -. trans- parent to opaque ; vitreous to resinous ; colourless, or white, grey, yellow, blue, red, brown ; streak white, or sometimes slightly coloured like the specimen in the earthy varieties ; H. 3-3 '5 ; G. 3-4 '7. Var. Hepatite is an impure earthy variety, emitting a fcetid odour by fric- tion or percussion. Cawk is a dirty white, earthy, opaque, massive variety. B. , etc. In the matrass decrepitates ; on C infusible, or fusible only on the thinnest edges (Dana says fusible at 3); when touched with HC1 and again heated tinges the flame yellowish-green ; with borax melts into a clear glass, which turns yellow or brown on cooling ; with soda fuses to a clear pearly mass, and is absorbed into the charcoal ; if a portion of the charcoal be then removed, moistened, and placed upon a polished surface of silver a black stain will be produced ; insoluble in HC1 or HNO 3 . Comp. Anhydrous sulphate of Barium ; with baryta 65 '63, and sulphuric anhy- dride 34-37, the formula will be Ba's or SOj Bao". No analysis of a Cornish or Devon specimen is known to the author. Foreign specimens have sometimes a large portion of the baryta replaced by strontia. Loc. The United Mines and Ale and Cakes, Gwennap, from the 170 fathom level, in semitransparent greenish -grey, yellowish, or brownish crystals, some like Fig. 137, which darken on long ex- posure to light ; St. Austell ; Herods- foot, in fine crystals ; Huel Mary Ann, Liskeard, in fine transparent colourless, or yellowish crystals, with pyrites and fluor (Figs. 133 and 136, and also the combination M O o d u); Trehane, ra- diated, with green fluor; Hennock; Res- tormel ; Menheniot, yellowish and trans- parent, in a lead lode ; Babbicombe Bay, on calcite ; Torquay ; Bridford, S. Devon ; also Surrey, Derbyshire, Staffordshire, Cumberland, Scotland, Norway, France, Germany, United States, &c. It is largely used as a paint; for giving a smooth surface to paper-hangings, &o. Angles. M M' = 101 40' O o = 127 18' MO 90 00 O d 141 09 Ma 129 10 dd 102 17 Oa 90 00 oo 74 36 Ob 90 00 Oz 115 42 u truncates the edge d a, n truncates the edge Mb. MOo, MOoa, MObo d, MOodu, MO;z, MO i? or are all Cornish forms. Basalt Jasper. See Porcelain Jasper. 14 BASALTINE. BERTHIERITE. Basaltlne. An old name for horn- blende. Base. A compound of a metal and oxygen, which by union with an anhy- dride can form a salt. Thus in an analy- sis of 100 grains of carbonate of lime there would be obtained 56 grains of lime and 44 grains of carbonic anhydride. Here the 56 grains of lime would be called the base. BAYLDONITE. Amorphous ; occurs in minute mam- millary concretions, with a drusy sur- face ; structure often somewhat reticu- late ; brittle ; fracture sub-conchoidal or uneven ; sub-translucent ; lustre strongly resinous ; grass-green to blackish-green ; streak siskin to apple-green ; H. 4*5 ; G. 5'35. B., etc. In matrass (fives off water and turni black ; on C fuses at first to a black bead; deflagrates; gives off an alliaceous odour; leaves a hard white metallic bead of Pb and Cu ; with borax gives Cu reactions ; soluble in warm HNO 3 , but not readily. Comp. Hydrated arseniate of lead and copper. The following is the mean of three analyses of Cornish specimens, by Professor A. H. Church : Arsenic anhydride 3176 Oxide of copper 30'88 Oxide of lead 30'13 Peroxide of iron, lime, and loss 2-65 Water 4'58 Total 100-00 With arsenic anhydride 31 '6, oxide of copper 32'8, oxide of lead 307, water 4'9, the formula will be' As a 3CuPb3H a (oxy- gen ratio for R AsH 2 = 4. 5 . 2) or PbO, 2CuO, As 2 O 5 + CuH 2 O 2 + H 2 O or As a O a Pbo"Cuo" 2 CuHo 2 + OH 2 . Loc. Found lately in Cornwall, by Mr. Tailing, of Lostwithiel, and de- scribed by Professor A. H. Church (Journal of the Chem. Soc., II. vol. iii., 265, 1865). It is often seen in old Cornish collections of minerals. Obs. An arseniate of lead and copper, from Huel Alfred, in Phillack, was analysed by Mr. Michell, in the year 1825, which may have been impure Bayldonite. It was mammilated ; gra- nular ; leek-green in colour. Its com position was PbO 31 '5, CuO 28 '0, As a O, 24-0, Fe a O 3 2-0, SiO 2 lO'O, H a O 2U ' Beekite. See Calcedony. Bell Metal Ore. See Stanntte. BKRAUNITE. Obliqu ; usually in foliated or ra- diated masses, with one distinct and one Indistinct cleavage, at an angle of 90 ; also columnar or investing; brittle; vitreous, pearly, or sub-metallic ; red or reddish-brown ; streak dirty yellow ; H. 2; G. 2-8-2-9. B. , etc. In matrass gives off water and turns darker ; on C alone fuses easily to a dark magnetic globule, colouring the flame bluish -green like Vivianite; with borax gives Fe reactions ; soluble in HC1. Comp. It is a hydrous ferric phos- phate. No analysis is published. Loc. Huel Jane, near Truro, on Vivianite and Niccolite; also Bohemia, Crimea, &c. Obs. It appears to be an altered Vivianite, from which it may be distin- guished by the colour of its streak. BERTHIERITE. [Haidingerite.] Rhombic? Occurs in indistinct confusedly aggregated prisms ; granular or plumose ; several longitu- cleavages, more or less distinct ; some- times a lamellar structure ; brittle ; opaque ; metallic, glimmering ; dark teel-grey, iridescent, or spotted red or brown ; streak dark grey or black : H. 2 to 3 ; G. 4 to 4'3. B., etc. In matrass fuses and gives faint yellow sublimate; with a strong heat forms a black sublimate, which is brownish-red on cooling ; on C fuses and yields a dark magnetic slag, depositing a white coating on the charcoal and giving a sulphurous odour ; with borax the slag gives Fe reactions ; soluble in HC1, yield- ing an odour of sulphuretted hydrogen. Comp. Sulphide of antimony and iron. No analysis, of a Cornish specimen is on record. Foreign specimens yield from 28-0 to 31'3 per eent. of sulphur, 52 '0 to 61 '0 of antimony, 9 '8 to 16 '0 of iron, with sometimes a little zinc or manga- nese. With antimony 51 7, iron, 17 '8, and sulphur 30 '5 the formula may be Fe 3 Sb 4 S 9 or 3FeS + 2Sb 2 S 3 ; with anti- mony 60'0, iron 10 '4, and sulphur 29 6 = Fe 3 Sb 8 S 15 or 3FeS-t-4Sb 2 S 3 ; with anti- mony 57 '0, iron 131, and sulphur 29 '9 =Fe 3 Sb 6 S 12 or3FeS 3Sb 2 S 3 or FeSb a S 4 or Sb 2 S 2 Fes". Loc. Near Tintagel ; and near Pad- stow, in the antimony mines ; also France, Germany, Hungary, United States, &c. Obs. It has been worked as an ore, but yields antimony of an inferior quality. It is always associated with other ores of antimony. It may be distinguished from antimonite and jamesonite by the con- siderable quantity of magnetic slag left on charcoal after heating. BERYL. BISMUTH. 15 BERYL. Hexagonal; usually in longitudinally striated prisms, like Figs. 188, 193, and 194, with an imperfect cleavage, parallel to O. ; sometimes in columnar aggregates, or massive ; brittle ; fracture, sub-con- choidal or uneven ; transparent to sub- translucent ; vitreous or resinous ; some- times colourless, but more usually wbite, green, blue, red, yellow, grey, sometimes parti-coloured, iridescent, or opalescent; streak white; H. 7 '5-8-0; G. 2 '6-2 '8. Var. Emerald is a fine green variety, used in jewellery. The colour, in some varieties at least, seems to be due to a minute proportion of chromium. The emerald has not been found in Cornwall. ., etc. In matrass unchanged, or altered in colour only ; on C alone the same, sometimes fuses on thin edges ; with borax forms a clear glass, often tinged green or yellow ; on adding pow- dered fluor spar the bead remains clear while hot, but becomes opaque on cool- ing ; not acted upon by acids. Comp. Anhydrous silicate of Alumi- nium and Beryllium, with usually small portions of Or. Fe. Ca. Mg. or Na.; the only mineral containing Beryllium found in the United Kingdom. Foreign speci- mens yield from 64'0 to 70'0 per cent, of silica, 14'0 to 21 '0 of alumina, and 11 '0 to 15-0 of berylla. With silica 66 '8, alumina 191, and berylla 141, the com- position will be Al 2 3Be6Si (oxygen ratio for protoxide, peroxide, and silica = 1 . 1 . 4), or Si 6 6 Al 2 oviBo" 3 . Loc. Huel Castle, St. Just, amor- phous; St. Michael's Mount, in small bluish crystals with topaz and cassiterite ; Mabe and Constantiue, in the granite quarries, in well-defined dull white crys- tals, embedded in fine-grained granite ; Lustleigh, Devon, in granite ; also Scot- land, Ireland, Norway, Sweden, Ger- many, France, Italy, Siberia, India, United States, &c. Obs. Crystals of beryl are sometimes very large. A crystal of beryl from the United States was 4 feet 3 inches in length, 2 feet 8 inches wide, and 1 foot 10 inches thick. Beryl may be distin- guished from quartz by its superior hard- ness and by the striation of its crystals, which is longitudinal instead of trans- verse ; from topaz by the form of its crystals (hexagonal prisms in beryl, rhom- bic prisms in topaz), and the imperfection of its cleavage. Bindheimite. See Bleinierite. BISMITE. [Bismuth Ochre. Oxide of Bismuth.] Cubical? massive and foliated ; earthy, pulverulent, disseminate ; friable or very brittle ; fracture earthy or conchoidal ; opaque ; glimmering or dull ; yellow, greyish, greenish ; H. '0 to 10 ; G. 4 '3. /?., etc. In matrass turns darker and gives off some water ; on C is readily re- duced to a grey, brittle bead, depositing a brownish incrustation ; soluble in HNO 3 often with a slight effervescence ; the solution yields a white precipitate when much diluted with water. Comp. Anhydrous oxide of bismuth, often with a little Fe and As, besides water absorbed from the atmosphere. No analysis of a British specimen is on record (unless the mineral called agnesite be the same, but impure). With bismuth 89'65, and oxygen 10*35, the formula would be Bi 2 or Bi 2 O 3 . A specimen from Germany yielded oxide of Bismuth 86 '4 per cent., equal to bismuth 75*3, and oxygen 111, besides oxide of iron 51, carbonic anhydride 41, and water 3'4. Loc. Botallack ; Levant ; Huel Her- land ; Cost all Lost, St. Eoach, in gra- nite ; Restormel Iron mine, with quartz and native bismuth. The mineral called agnesite, which is probably an impure bismite, occurred at Huel Coates, St. Agnes ; also Germany and Siberia. Obs. It may be distinguished from the carbonate of bismuth by its very slight effervescence in HNO 3 . BISMUTH. [Native Bismuth.] Hexagonal ; In rhombohedrons, with an angle of 87 40' (Fig. 203) ; cleavage basal, very perfect forming an angle of 123 36' with the face of the rhombohedron ; often macled, or dendritic ; mossy, granular, compact, foliate, or disseminate ; sectile or almost malleable ; opaque ; lustre metallic ; reddish white, often an iridescent tar- nish ; streak grey and shining ; H. 2*0- 2'5 ; G. 9'6-9-S. B., etc. In matrass melts and forms a yellowish sublimate ; on C fuses at 1 and volatilizes, forming a brownish incrus- tation near the assay ; sometimes yield- ing an alliaceous odour, and depositing a white coating at some distance from the assay, from the presence of arsenic ; soluble in HNO 3 ; the solution yields an abundant white precipitate on the addition of much water. Comp. Bismuth, with traces of ar- senic, sulphur, or tellurium. No analysis of a British specimen is on record. Loc. Botallack, in small crystals on jasper; Levant, St. Ives Consols, lamel- lar, very fine and pure ; Gt. Dowgas j Dolcoath, in purple and greeH fluor; 16 BISMUTHINITE. BITUMEN. Huel Herland ; Huel Sparnon, in fea- thery masses, with erythrine and smal- tite ; Trugoe, near St. Columb ; also Cumberland, Scotland, Norway, Sweden, France, Germany, Spain, United States, &c. Obs. The bismuth of commerce is mostly obtained from native bismuth. Masses of bismuth of several pounds weight are said to have been found loose in the soil near Redruth. Cupreous bis- muth is said to occur at Huel Buller, and arsenical bismuth at St. Just. Bismuth is usually associated with tin, cobalt, or silver ores. The usual minei's test for bismuth is to heat the ore on a shovel, when it melts into globules readily. A rude assay is often made by heating the ore, without fluxes, in a crucible, when the metal fuses, and from its high spe- cific gravity sinks to the bottom. A ngles. RR = 87 40' Ro 123 36 BISMUTHINITE. [Bismuthine. Bismuth Glance.] Rhom- bic ; in acicular prisms, like Figs 98 and 99 ; deeply striated longitudinally, with perfect cleavages, at right angles to each other, and parallel to a. and o.; also in columnar aggregates ; massive, with fo- liated, radiated, or fibrous structure ; granular ; compact ; disseminate ; brittle, or sectile ; opaque ; metallic ; tin-white to lead-grey ; often iridescent ; streak grey, shining; H. 2 '0-2 "5; G. 6 '4-6 '6. B.. etc. In matrass gives a yellowish sublimate ; on C fuses at 1, boils, coats the charcoal yellow, and gives off a sul- phurous odour ; tinges the flame blue ; may be entirely volatilized in the O F ; in R F yields a grey, somewhat brittle bead of Bi ; decomposed by hot HNO 3 , which dissolves the Bi and leaves the S ; the solution diluted with a large quan- tity of water yields an abundant white precipitate. Comp. Anhvdroua sulphide of bis- muth, often containing small quantities of Fe and Cu. The following are analy- ses of Cornish specimens : Bismuth ... 72 a; 49 ... 78 ; 00 ... 68*53 Iron 3'70 ... T04 ... 2'90 Copper 3'81 ... 2'42 ... 2'98 Sulphur ... 20-00 ... 18-42 ... 19'33 Silica ... ... 5-01 Totals... 100-00 ... 99-88 ... 9875 a. and c. are by "Warrington, b. is by Rammelsberg. With bismuth 8074, and sulphur 19 '26 (Bi 208), the formula will be Bi 3 S 3 . Loc. Botallack ; Huel Cock ; Levant ; Balleswidden ; Dolcoath ; East Pool, in quartz ; Pednandrea, some of the prisms macled at one end and pointed at the other so as to bear some re- semblance to a pin ; Huel Herland ; Huel Sparnon ; Fowey Consols ; Lanes- cot ; St. Columb, in stream works, as water-worn pebbles, like stream tin ; Huel Arthur, Calstock ; George and Charlotte mines, with childrenite ; Great Dowgas ; Devon and Cornwall United Mines, Devon, in fine crystals ; Ivy Tor mine, near Okehampton ; also Norway, Sweden, Germany, &c. Obs. It may be distinguished from all similar minerals which occur in Devon or Cornwall by the white precipitate which falls from its solution in HNO 3 on the addition of water. It usually occurs in veins or cavities ("vugs") in quartz, slate, or granite. Fig. 98 is a prism ; Fig. 99 a section of the same. Angles. MM = 91 00' M a 134 30 ba 90 00 Bisulphuret of Copper. See Covelline- Bisulphuret of Iron. See Pyrites and Marcasite. Bitter Spar. See Dolomite, BITUMEN'. Asphaltum. Mineral Pitch. Amor- phous, brittle, sectile, or plastic ; frac- ture conchoidal or hackly ; opaque ; lustre resinous, brilliant to glimmering ; brownish-black or velvet-black ; streak greyish; H. to2'0, G. 1-1 '2; frictio- electric. Var. 1. Naphtha includes the fluid varieties. 2. Petroleum. Rather thicker than common tar, but hardens by keeping; has a bituminous odour ; is soluble in ether and alcohol, probably a mixture of naphtha and asphaltum. 3. Elaterite. Elastic and flexible, like caoutchouc. 4. Asphaltum. Solid ; fracture con- choidal ; almost entirely soluble in ether. B. , etc. All burn with a bright smoky flame. Asphaltum melts at about 100 C, and when burnt leaves a small quan- tity of incombustible ash. Comp. All are hydro-qarbons of very uncertain and variable composition. Asphaltum contains from I'O to 12 "0 per cent, of oxygen and nitrogen. LOG. Petroleum. Huel Unity and Huel Jewell, G wen nap ; Carharrack Mine, St. Day ; North Treskerby, Red- ruth ; Chudleigh, Devon. Asphaltum. Poldice Mine, coating BLACK COPPER. BLENDE. 17 quartz ; Car-barrack ; South Huel Towan ; Cook's Kitchen ; North Treskerby ; Great HuelCrofty; North Roskear; also Derby- shire, and other parts of England ; Scot- land, Germany, Greece, West Indies, &c. Obs. It is probable that the above minerals are distinct species, and not mere varieties. Black Copper. See Melaconite. Black Hematite. See Psilomelane. Black Jack. See Blende. Black Lead. See Graphite. Black Sulpburet of Silver. See Ar- gentite. BLEINIERITE. [Bindheimite.] Amorphous, reniform, stalaciitic, spheroidal, investing ; com- pact, with curved lamellar structure, or earthy ; brittle ; translucent to opaque ; vitreous, resinous, or dull ; yellow, some- times white, grey, brown ; streak like the colour, usually yellow; H. 2*0 to 4'0; G. 3'9 to 5-0. B., etc. In matrass gives off water and becomes darker ; on C fuses at 1 (?) ; Is readily reduced to a grey, brittle globule of antimony and lead, coating the charcoal yellow near the assay, and white outside the yellow ; sometimes a very slight garlic odour ; with soda, after long blowing, yields a malleable bead of lead ; soluble in HC1. Comp Hydrated Antimonate of Lead. The following are analyses of Cornish specimens : a. b. c. d. Oxide of an- timony ... 42-22 42-44 4670 47 "36 Oxide of lead 47-04 46 '68 43 "94 40 '73 Oxide of iron 1*44 Lime 1'34 Oxide of ar- senic trace Water 11 '50 1198 6'46 11-91 Totals ... 100-76 101 10 99 '88 100 '00 a. b. and c. were analysed by Heddle, d. by Percy, a. and b. were white, c. was brown. With antimonic oxide 42 '2, oxide of lead 46 5, water 11 '3, the formula may be written Pb3b 2 3H 2 , or Sb 2 O 4 Pbo"l 30H 2 . Loc. Trevinnick Mine, Endellion, in large yellow detached masses, near the surface ; also on Jamesonite, with anti- monite and other ores of antimony ; also found in Norway and Siberia. Obs. It appears to be a product of the decomposition of Jamesonite. BLENDE. [Sphalerite. Black Jack.] Cubical, in cubes, tetrahedrons, rhombic dode- cahedrons, octahedrons, &c. ; often macled (Figs. 1, 2, 3, 8, 10, 35, 37, 39, 42, 52, 56], with a highly perfect dode- cahedral cleavage ; also botryoidal, fi- brous, massive, compact, plumose, radi- ated, lamellar, or granular ; brittle; fracture conchoidal or uneven, but not often to be observed ; semi-transparent to sub-translucent ; lustre sub-metallic, adamantine, or resinous ; yellow, brown, red, black, rarely green or white ; streak white or light brown; H. 3.5-4; G. 3 '9-4 2; some varieties pyro or frictio- electric. Var. Cleiophane is a pure white variety ; Marmatite and Christophite are dark brown or black, and contain 10 '0 per cent (or more) of iron ; Przibramite is a variety containing from I'O toS'O per cent, of cadmium. It is usually dark in colour, and often granular or fibrous. B., etc. In matrass decrepitates, and sometimes changes colour, or yields a alight white or yellowish sublimate ; on C infusible, or fusible oi.ly on thin edges ; with borax or soda and a strong heat ex- hibits a light green incandescence, and deposits an abundant white incrustation, which when treated with Co becomes green ; soluble in strong HC1 or HNOs, giving off H 2 S. Comp. Anhydrous sulphide of zinc. The following are analyses of Cornish specimens : a. b. Zinc 58-64 ... 43'00 Iron 11-96 ... 22'50 Copper 0'80 Sulphur 28-64 ... 31 '50 Silica 0-76 . Totals 100-00 ... 97-80 a. is by Thomson, b. is from Huel Ann, analysed by Gregor. The sp. gr. of a. was 4 "049, the colour was blackish-brown. Foreign specimens yield from 44 '6 to 66 '3 of zinc, to 18*2 of iron, 32 '1 to 33 '8 of sulphur. With sulphur 33, and zinc 67, the formula will be ZnS. Loc. Botallack Mine ; Goonhavern Mine, Newlyn ; West Huel Darlington ; St. Agnes, in fine crystals (Figs. 37, 39, &c.); Huel Sperries ; Nangiles ; Huel Vor ; Huel Rose ; Huel Penrose ; Lanes- cot ; Huel Brothers, Calstock ; Par Con- sols ; Huel Crofty ; Huel Unity, white, mammillated, and fibrous; Fowey Con- sols, fibrous, white, and transparent (Cle- iophare), andcadmiferous ; Landkey, near Barnstaple; Beeralston; Tamar Mines ; Hennock; Combemartin; Huel Betsy and Huel Friendship, Tavistock; and many other localities in Cornwall and Devon. 18 BLOODSTONE. BLOWPIPE. Obs. By oxidation it sometimei gets covered with a coating of Goslarite. Blende often accompanies ores of lead, tin, and copper, and is usually considered a good sign. Hence the expression, "Jack rides a good horse." A ngles. a a = 90 00' o a = 125 16' dd 120 00 ma 154 46 oo 109 28 mo 150 30 oo' 70 32 Blistered Copper Ore. See Chalcopy- rite. Bloodstone. Se Calcedony (Helio- trope.) Blowpipe. An instrument used for the purpose of directing the flame of a lamp or candle so as to concentrate its power. It is much used in testing minerals. The complete blowpipe or pyrognostic examination of a mineral consists of eight or more distinct opera- tions, but some of these may usually be omitted with advantage. The operations are as follows : 1st. Heating the assay in a small tube of hard glass, sealed at one end, and known as an "ignition tube," "closed tube," or "matrass." The matrass should be two or three inches long, and from one-eighth to one-quarter inch in diameter. It must be clean and dry. A spirit lamp is the best source of heat for this experiment, and the assay should be heated gradually, the better to see the changes produced ; at the close of the operation the flame may be urged with the blowpipe if no change, or but little, haa been already effected. The changes to be looked for are a., changes of colour ; b. , decrepitation ; c., deposition of moisture, or a sub- limate, on the cool part of the tube; d., the evolution of a rapour or peculiar odour. 2nd. A fragment of the substance to be examined is placed in a tube about six inches long, open at both ends, the tube being held in an inclined position over the flame. As before, the flame may be urged by the blowpipe towards the close of the experiment. The effects to be noted are the same as in the first instance, but the sublimates will some- times be different, and the odours more distinct. 3rd. A little of the coarsely-powdered assay is placed in a small cavity scooped on the surface of a piece of charcoal with a penknife. The flame of a candle or of an oil lamp is then directed upon the assay by means of the blowpipe, using the "oxidising flame" ("OF"). The effects to be observed are a., degree of fusibility; b., evolution of vapour or odour ; c., deposition of an incrustation on the cool part of the charcoal support ; d., reduction to a bead of metal ; e., non-volatile residue; f., tinging of the tip of the flame. 4th. If the non-volatile residue is white, a drop of a strong solution of Cobaltic nitrate ("Co") should be dropped upon it, and the mass again heated, noting the tint produced by this treatment. 5th. If the residue be any colour other than white it should be mixed with a little dry carbonate of. soda ("soda") and heated strongly, using the "reducing flame" ("RF"). In some very obstinate cases a little borax or cyanide of potas- sium may be mixed with the soda with advantage. The result to be looked for is the production of a bead of metal. If the portions of reduced metal be very small they may escape observation ; in this case the portion of charcoal round the assay should be cut out, ground up ! with water in a small mortar, and the ! light carbon and soluble soda washed I away. Any shining particles of metal I will then be easily detected. 6th. Make a small loop in the end of a i piece of platinum wire, heat it in the i flame of the spirit lamp, dip it into pow- j dered borax, hold it again in the flame 1 until the borax has melted into a clear glassy bead, add to it a very little of the powder of the substance to be tested, heat it again, in the OF first, then RF if no distinct colour is produced, take a little more of the assay and repeat the operation, several times if necessary. 7th. Repeat the sixth experiment, using a bead of microcosmic salt (" micro.") instead of the borax. 8th. Hold a fragment of the substance under examination with a pair of plati- num-pointed forceps, and direct the tip i of the OF upon it. Observe any change of tint that may be produced in the flame, and also the degree of fusibility (see " Scale of Fusibility "), if the speci- men be fusible. In the absence of platinum forceps, a piece of platinum wire tightly twisted round the specimen will sometimes suf- fice. The eighth operation is of greatest use in the absence of such substances as give sublimates in the matrass or open tube, incrustations on charcoal, and coloured beads with micro, and borax (see BLUE COPPEE. BBAUNITE 19 operations 1 to 7). When such results have been observed in the first seven operations the eighth should be omitted, or the platinum will be injured. An assay piece the size of a mustard eed will generally be sufficient, and will be more manageable than a larger piece. For the detection of substances present in small quantity, however, it will be sometimes necessary to take a larger piece. The results of each operation should be carefully compared with the blowpipe tables in the first part of the book. Blue Copper. See Covelline and Ches- sylite. Blue Iron Earth. See Vivianite. Blue John. A Derbyshire name for Fluor. Blue Lead. See Galena. Blue Malachite. See Chessylite. Bog Iron Ore. See Limonite. Bog Manganese. See Wad. Borate. A compound of Boric anhy- dride with a metallic oxide; or Boric acid in which the hydrogen has been replaced by a metal. Borax. Borate of Soda. It is much used in the blowpipe examination of minerals. Bornite. See Erubescite. Botallackite. See Atacamite. Botryoidal. Like a bunch of grapes. Malachite and Blistered Copper Ore are examples of botryoidal minerals. When the rounded prominences are larger and less distinctly separated, the mineral is mammillate ; when the prominences are very irregular in size, and the larger ones themselves broken up by smaller prominences, the specimen is said to be reniform ; when almost spherical, the term globular is used. BOURNONITE. [Endellionite.] Khombic ; usually in modified prisms, like Figs. 120 and 123, or macles, like Fig. 121 ; also massive, granular, compact, investing, or disse- minate ; brittle ; fracture sub-conchoidal or uneven ; opaque ; lustre metallic, brilliant ; steel grey to blackish-lead grey ; streak the same ; H. 2 '5-3 ; G. 57-5-9. Tar. Wheel ore and cog-wheel ore are names applied to finely macled varieties, somewhat like Fig. 121. B., etc. In matrass decrepitates and yields a dark red sublimate ; in the open tube gives a sulphurous odour and a white sublimate of oxide of antimony ; on C fuses at 1, and gives a white coat- ing, and afterwards a yellow one nearer the assay ; by alternately making use of the O F and R F a bead of Cu is pro- duced, more readily on the addition of a little soda ; decomposed by HNO3, which forms a blue solution, and leaves a resi- due of sulphur, antimony, and lead. Gomp. Anhydrous sulphide of lead, copper, and antimony. The following are analyses of Cornish specimens : a. b. c. d. Antimony ... 24-23 28 "50 26 '30 25 '00 Lead 42-62 39'00 40'80 41 '00 Copper 12-80 13'50 12'70 1300 Iron 120 TOO VOO Sulphur 17-00 16-00 20 '30 20 '00 Totals 97-85 98 00 10010 100 '00 a. was a specimen from Endellion, analysed by Hatchett ; b. from Nansloe, by Klaproth ; c. and d. were Cornish specimens, analysed by Field and Smith- son. With antimony 24 '8, lead 42 '4, copper 12-9, and sulphur 19 '9, the formula will be SbPbCuS 3 or Sb 2 Pbs" 2 (Cu 2 S 2 ). Loc Huel Boys, Endellion (Figs. 120, 123), where it was first discovered by Count Bournon ; St. Merryn, Padstow ; Nansloe, Helston ; Budock Vean, near Falmouth, crystallised, compact, and mas- sive ; Herodsfoot, in crystals, like Fig. 121, in simple crystals, like Fig. 120, filling hollow crystals of galena, accom- panied with Barytes, Fahlerz, and hacked quartz, or massive ; Beeralstone ; also France, Germany, Itaiy, Mexico, Chili, Peru, &c. Obs. It is usually associated with an- timonite, jamesonite, galena, chalcopy- rite, and chalybite. Angles. MM = 93 40' O o = 13ft 8 17' Mb 136 50 Ou 146 45 Oa 90 00 Oy 127 20 Ob 90 00 ab 90 00 On 138 06 ef 118 04 Ox 154 27 e b 154 52 Bovey Coal. See Coal. Brachydiagonal. The shorter lateral axis of crystals in the rhombic system is so called ; also a cleavage plane parallel to this and the principal axes. Brass Ore. An intimate mixture of Blende and Chalcopyrite, found at some mines in Cornwall. BRAVNITE. Tetragonal, the pyramid scarcely dif- fering from Fig 1 ; often in macles of three ; also massive, brittle ; fracture uneven; opaque; lustre sub-metallic; colour dark brownish-black ; streak the same ; H.6-6'5 ; G. 4'7 to 4 '82. #., etc. In matrass no change ; on C infusible ; with soda, borax, or micro. 20 BRECCIA. BBOOKITE. gives Mn reactions ; the powder soluble in warm HC1 with evolution of 01, some- times a little gelatinous silica is left un- dissolved. Comp. Anhydrous proto-peroxide of manganese with s 'me silicate of manga- nese. No analysis of a British specimen is on record. Foreign specimens yield from 80 to 87 per cent, of protoxide of manganese, 8 to 10 per cent, of oxygen, and 8 '0 per cent, of silica. With oxide of manganese 82'1, oxygen 9'3, and silica 8'6, the formula may be 4Mn 2 + Si O 2 or MnO + 3Mn 2 O 3 + MnSiO 4 . Loc. It is said to have been found in the manganese mines near Launceston ; found in Piedmont, Germany, and Nor- way, Elba, India, &c. Breccia. Amass of angular fragments of rock, cemented together by some other material. Brick Red Copper Ore. See Cuprite (Tile Ore). Bright White Cobalt. See Cobaltite. Brittle. Easily broken. On attempt- ing to cut a brittle mineral the fragments usually fly in powder from the edge of the knife with some considerable degree of force. BROCHANTITE. [Warringtonite.] Rhombic ; in tabu- lar or short prismatic crystals, vertically striated, and in appearance somewhat like Fig. 189, but shorter ; cleavage per- fect, parallel to O ; also in acicular groups or drusy crusts ; or massive, reniform, columnar ; brittle ; fracture conchoidal; transparent to translucent; lustre vitreous, pearly on cleavage plane ; emerald green to blackish-green ; streak bright green; H. 3 to 4; G. 37 to 3'9. Var. Brochantite, crystals vertically striated; H. 3 "5-4; G. 378-39. War- ringtonite occurs in non-striated crystals, in form like a doubly curving wedge ; paler green than ordinary brochantite ; H. 3-3-5; G. 3'39-3'47. Woodwardite may also belong here, but is described under Langite. B., etc. In matrass yields water with an acid reaction and turns black ; on fuses and yields a bead of Cu, with soda gives the reaction for sulphuric acid ; insoluble in water, soluble in HC1, the solution yields an abundant white preci- pitate with solution of Ba Cl. Comp Hydrated cupric sulphate. The following are recent analyses of Cornish specimens : a. b. c. Sulphuric anhy- dride 172 18-93 1673 Oxide of copper 68 '8 68 '27 68 '24 Oxides of, iron and zinc I'O Lime 08 Water 13 '2 12'22 14'64 Insoluble matter 0'58 Totals 101-0 100-00 99 '61 a. is by Pisani, b. by Warrington, c. by Maskelyne. With sulphuric anhydride 19 '9, oxide of copper 69 -0, and water 111, the for- mula may be 7Cu 36 5H 2 or S 2 O 4 Cuo" 2 + 5CuHo 2 . Loc. Several specimens, both of Bro- chantite and Warringtonite, have been found in Cornwall; it also occurs in Cumberland, Germany, Ural, Mexico, Chili, &c. Bronzite. See Diallage. BROOKITE. Rhombic; crystals usually more or less tabular, like Fig. 147, and striated, dull, or uneven ; cleavage macrodiagonal, sometimes distinct ; brittle ; fracture con- choidal or uneven ; translucent to opaque ; lustre adamantine or sub-metal- lic ; reddish or yellowish-brown ; streak yellow or white ; H. 5'5-6 ; G. 4 to 4'2. B. , etc. In matrass unchanged ; on C infusible ; with micro, a brownish-yellow glass, &c., like anatase ; insoluble in HC1 or HNO 3 . If the powdered mineral be fused with potash on Pt foil, dis- solved in HC1, and the solution boiled with metallic tin, it becomes violet, and red on dilution with water. Comp. Titanic anhydride, Ti or TiO 2 , like anatase and rutile. No analysis of a British specimen is on record. Foreign specimens contain from 94 to 99 per cent, of TiO 2 , the rest being peroxide of iron, alumina, or water. Loc. Virtuous Lady Mine, in micro- scopic crystals, embedded in chalybite, with chlorite and anatase; also Wales, France, Switzerland, Sicily, United States, &c. Obs. Titanic anhydride is trimor- phous, being pyramidal in anatase and rutile, but with different parameters ; and rhombic in brookite. The face b is usually striated parallel to its intersec- tion with M. A ngles. MM' = 80 10' b9 - 104' 06' M b 139 5S b 112 12 BEOWN HEMATITE. CAXCEDONY. 21 Brown Hematite ; Brown Iron Ore ; Brown Ochre. See Limonite. Brown Lead Ore. See Pyromorphite. Brown Spar. See Dolomite. Buntkupferz. See Erubescite. C. Cairngorm. See Quartz. GALA MINE. [Smithsonite (Dana).] Hexagonal; in obtuse rhombohedrons, often curved ; sometimes tabular ; perfect rhombohe- dral cleavage ; crystals usually indistinct ; often compact, with the appearance of chalcedony ; reniform, botryoidal, fi- brous, stalactitic, investing ; cellular, granular, earthy, friable ; brittle ; frac- ture conchoidal or uneven ; transparent to opaque ; vitreous, pearly, or dull ; colourless, but more frequently white, or various shades of green, yellow, grey, or brown ; streak white or slightly coloured ; H. 5 ; G. 4-4*5. ., etc. In matrass sometimes decre- pitates and loses colour ; on C infusible ; moistened with Co and again heated turns green on cooling ; with soda yields an abundant white coating of oxide of zinc, which becomes green when treated with Co; when cadmium is present a brown coating is also formed; soluble with effervescence in HC1. Comp. Anhydrous carbonate of zinc. No analysis of a specimen from Cornwall or Devonshire has been made, but a spe- cimen from Somersetshire yielded Oxide of zinc 64 '8, carbonic anhydride 35*2, which agrees exactly with the for- mulae ZnC or ZnCO 3 or COZno". Some foreign varieties contain as much as 53 '0 per cent, of carbonate of iron, or 15 '0 per cent, of carbonate of manganese. Loc. Huel Mary, Lelant ; Fowey Con- sols ; Great St. George Mine ; also Somer- setshire, Derbyshire, Cumberland, Wales, Scotland, Ireland, Belgium, France, Spain, Italy, Germany, Hungary, Sibe- ria, United States, &c. Obs. It commonly occurs in limestone rocks, associated with galena and blende. Calcareous Iron Ore. See Chalybite. Calcareous Spar. See Calcite. Calcareous Uran Mica. See Autunite. CALCEDONY. Calcedonic Quartz ; amorphous ; bo- tryoidal, stalactitic, nodular, concre- tionary, or lining cavities in quartz or other f ocks ; brittle ; fracture flat con- choidal or splintery ; semi-transparent to opaque ; resinous or waxy; shining, glimmering; white, grey, yellow, red, brown, green, blue, black ; often clouded, striped, or mottled ; streak white ; H. 6-6-5 ; G. 2-6 Var. 1. Calcedony proper; usually stalactitic or botryoidal ; often very deli- cate tints. 2. Carnelian ; reddish or brownish, pale or deep in tint. 3. Chrysoprase ; apple-green ; the co- lour due to oxide of nickel, from 0'4 to 1*0 per cent. 4. Prase ; translucent and dull leek- green. The name is also applied to hyaline quartz when of the same tint. 5. Plasma ; sub-translucent ; bright green, sometimes dotted with white. 6. Heliotrope or bloodstone is the same, dotted with red. The green is often duller in heliotrope. 7. Agate is a variegated calcedony ; the colours in bands or clouds. 8. Moss-agate or Mocha-stone, the same, but the markings are dendritic or moss-like. 9. Onyx is a banded agate, the bands even and distinctly separated. In fortifi- cation agate the bands are in angular lines, something like the ground plan of a fortification. 10. Sardonyx is the same, but some of the layers are like carnelian. 11. Agate Jasper is a jasper with vein- ings or markings of calcedony. 12. Siliceous sinter is an irregularly cellular calcedonic quartz deposited from waters holding silicates in solution. 13. Flint is like Calcedony, but nearly opaque, and of duller tints ; usually grey, smoky-brown; or brownish-black; the exterior is usually white, from a thin coating of silicate of lime ; lustre glimmering ; fracture deep conchoidal. Thin splinters often exhibit organic markings when viewed by transmitted light. 14. Hornstone, like flint, but more brittle, and the fracture splintery. 15. Basanite, Lydian Stone, Touch- stone ; velvet-black ; compact, and the fracture not splintery. It is often slightlj laminated. 16. Jasper. It is opaque ; yellow, red, brown, dirty-green, greyish-blue, brown- ish-black ; striped ; the colour is gener- ally due to oxide of iron. It is usually accounted a separate sub-species, and is described as such. 17. Beekite is a calcedonic pseudo- morph, after various species of coral. It often contains some of the original car- bonate of lime. ., etc. In matrass sometimes changes colour, and usually yields a little water ; on C alone infusible ; with soda dissolves CALCITE. CALCITE. readily with effervescence to a clear glass, of a colour like that of the assay ; soluble in borax, with generally a Fe reaction ; insoluble in micro. ; insoluble in acids ; slightly soluble in KHO. After strong heating has a sp. gr. of 2 '2. Comp. Silicic anhydride or silica, SiO 2 , like hyaline quartz usually con- tains some oxide of iron, nickel, or man- ganese, and a little water. A grey cal- cedony from Hungary afforded Silica 98 '97, peroxide of iron 53, carbonate of lime 0'62. A clear red carnelian yielded 0*5 of peroxide of iron. An apple-green chrysoprase from Silesia yielded I'O per cent of oxide of nickel. Loc. a. Calcedony. Trevascus Mine, Gwinear ; Ponsanooth, in greenstone ; North Pool and Pednandrea, with cassi- terite, very beautiful specimens, white, pale yellow, grey, brown, blue, black, some with a pearly grey enamel or incrustation ; Dolcoath; East Pool ; Botallack ; Boscas- well; Balleswidden, and most of the St. Just mines ; Goonhilly Downs ; Lanescot ; Huel Maudlin ; Beeralstone ; Haytor ; near Sidmouth ; near Beer ; Blackdown- hills ; Torquay ; Broadhembury and Whitstone Pits, pseudomorphous after coral (Beekite) ; in rhomboids and six- sided plates, pseudo. after calcite and dolomite, at St. Just and North Eoskear ; in tabular crystals, pseudo. after barytes, in fine specimens at Herodsfoot and Huel Mary; after calcite and datholite at Haytor (Haytorite) and North Eos- kear. b. Flint. Orleigh Court, near Bide- ford, with chert, green earth, and hema- tite forming a breccia ; Dunscombe-hill, near Sidmouth, Blackdown-hills, and other localities in Devonshire, not rolled ; Branscomb cliff ; White cliff, near Chard ; Buckland Brewers ; Haldon ; Tregoning- hill and Trewavas, chipped ; Vorlas, Ludgvan ; Marazion beach ; Looe Bar, Portreath, and most of the beaches of Cornwall, and the Scilly Isles. c. Agate. Carn Brea-hill, south-east side ; Huel Sparnon, Looe Bar, and near Gweek (fortification); Budleigh Salter- ton, in a bed of rolled pebbles ; Haytor ; Mary Church, Kynance, c. d. Prase. North Eoskear, in white quartz ; Garras Mine, near Truro. e. Carnelian. Blackdown-hills, Devon. f. Hornstone. East Tamar; Beeral- stone, pseudomorphous after fluor; Pen- mare Point; Herodsfoot ; Orleigh Court; White cliff ; Branscomb cliff ; Haldon. CALCITE. [Calc Spar.] Hexagonal; in rhombo- hedrons, threte and six-sided prisms, ! with trihedral summits ; in scalenohe- drons ; in hexagonal plates, lens-shaped j crystals, &c., see Figs. 188, 195, 197, I 200, 201, 217, 218, 222, 223, 226, 227, all of which, with many others, have been observed in Cornwall or Devon ; with three highly perfect cleavages, forming angles of 105 '5; also massive, compact, granular, or lamellar ; stalac- titic, coralloid, fibrous, nodular, &c., or pseudomorphous after aragonite, gyp- sum, felspar, and other minerals ; brit- tle ; fracture conchoidal, granular, or earthy ; transparent to opaque ; lustre vitreous to pearly, brilliant to dull; colourless, or white, grey, yellow, pink, red, green, blue, brown, black, parti- coloured ; streak white, or slightly tinged like the colour; H. 2 '5-3; G. 2 '5-2 "8. strongly doubly refractive when trans- parent. Var. 1. A pure transparent variety, with very perfect rhonibohedral cleavage is called Iceland spar or doubly refrac- ting spar. 2. A variety composed of small scalen- ohedrons projecting from a mass is called dog-tooth spar. 3. Satin spar is a fine fibrous variety. 4. Schiefer spar is lamellar, friable, and tender ; by some supposed to be pseudomorphous after selenite. 5. Marble is massive and granular. 6. Limestone is massive and compact. 7. Stalactite and Stalagmite are varie- ties formed by deposits from water con- taining lime in solution. 8. Oolite is composed of small rounded concretions. 9. Pisolite, of larger concretions. 10. Swinestone is a variety which emits a foetid odour when broken. 11. Chalk is an earthy variety, made up of fragments of minute shells, sponges, &c. Many other varieties have received distinct names. -B., gtc. In matrass decrepitates, loses colour, or remains unchanged ; on C in- fusible, but becomes alkaline, glows, colours the flame brick red, especially after being moistened with HC1 ; with soda fuses to a clear mass at first, but finally the soda sinks into the charcoal and leaves a white infusible mass ; solu- ble in borax with effervescence, the bead if saturated becomes white and opaque on cooling, freely soluble even in lumps with brisk effervescence in dilute HC1. Comp Anhydrous carbonate of cal- cium, but often containing a consider- able percentage of the carbonates of iron, magnesia, or manganese. No analysis CALCITE. CASSITEEITE. 23 of a specimen from Corn wall or Devon is known to the author. With lime 56 '0, and carbonic anhydride 44 '0, the formula will be CaC or Ca CO 3 or COCao". Loc. a. Calcite. Botallack.HuelOwles, and other St. Just mines, in pale pink crystals, like Figs. 200 and 223, and other forms ; Huel Towan ; Huel Penrose, near Helston, in pink masses ; Binner Down ; Cadgwith, in large plates and thick veins ; Kynance, Lizard Point, and other parts of the Lizard district, often in veins ; West Huel Grambler, dog- tooth spar in masses of quartz and com- pact fluor, and in skeleton crystals ; Huel Buller; North Roskear; Pol- gooth ; Gari as ; Huel Mary Ann, Men- heniot; Huel Alfred; Tintagel, Bos- castle, and Delabole ; Beeralstone and Beerferris, in beautiful pale lilac rhom- bohedrons ; Huel Friendship ; Babbi- combe Bay ; Combemartin ; Teignmouth and Torquay, and many other localities ; in fissures on the coast ; many mines near Liskeard, in fine crystals ; in quar- ries near Beerhead (Beerstone), with green earth, crystals with brilliant facets, also massive and compact ; at Exeter, in an amygdaloidal rock ; Plymouth, in very fine scalenohedrons and other crys- tals, like Fig. 222, in cavities in the limestone rocks ; and many other locali- ties in the two counties. b. Schief er Spar. Plymouth, Delabole, Tintagel, with quartz and albite ; Pol- gooth ; North Roskear ; Botallack ; Beer- alstone ; also Derbyshire, Cumberland, and many other parts of England ; Wales, Scotland, Ireland, and most other countries. Obs. Calcite may be distinguished from aragonite by its crystalline form, cleavage, inferior hardness, and sp. gr., and by its not falling to pieces when heated in a matrass. Low hexagonal prisms, lens-shaped crystals, and tabular forms are said to prevail in Devon and Cornwall. Some of the masses of the pure transparent variety from Iceland (Iceland Spar) are very large. A single cleavage rhombohedron has been observed, more than six yards in length and three yards high (Dana, Syst. Min., 1868, p. 679). Chalk, marble, lime- stone, and oolite are rather rocks than minerals. Calcite passes into dolomite from the presence of MgCO 3 , chalybite through FeCOs, calamine through ZnCO^. Above 75 different faces have been de- scribed, including 41 distinct rhombohe- drons, 85 scalenohedrons, and seven hex- agonal pyramids. A ngles. R R = 105 50' c o = 90 00' cc' 120 00 eg 116 15 gg 134 57 rr 144 20 Cann. See Fluor. Capillary. Hairlike, in fine fibres, like "acicular," but not straight. Capillary Pyrites. See Millerite. Capillary Red Oxide of Copper. See Cuprite (Chalcotrichite). Carbonate. A compound of a metallic oxide with carbonic anhydride, or car- bonic acid in which the hydrogen is dis- placed by a metal. The mineral car- bonates have a hardness not exceeding 5, so that they will not strike fire with steel, nor scratch glass. The anhydrous carbonates crystallize in the hexagonal system, and cleave into rhombs with an angle of 105 or nearly ; rhombic with prisms of 120 and 60 ; or oblique with prisms of 105 and 75. The lustre is vitreous or pearly, colours very varied. They are the typical spars. The hydrous carbonates vary much in crystallization. All the mineral carbonates when pow- dered effervesce in strong and warm HC1. Some effervesce briskly even in a lump with dilute and cold HC1. The carbonates found in the two counties are : Calcite, Dolomite, Chalybite, Calamine, Aragonite, Cerussite, Cromfordite, Diallogite, Malachite, Chessylite. The first eight are anhydrous, the last two are hydrous. Carbonate of Copper. See Malachite and Chessylite. Carbonate of Iron. See Chalybite. Carbonate of Lead. See Cerussite. Carbonate of Lime. See Calcite and Aragonite. Carbonate of Lime and Magnesia. See Dolomite. Carbonate of Manganese. See Diallo- gite. Carbonate of Zinc. See Calamine. Carnelian. See Chalcedony. CASSITERITE. [Oxide of Tin. Tin-stone.] Pyramidal, like Figs. 61 to 71 and Fis. 77 ; crystals often imperfect and usually macled, with some faces striated, rough, or uneven; also in rolled fragments, or botryoidal with radiated concentric structure ; massive, disseminated ; pseudomorphous after f el- spar, &c.; brittle ; fracture uneven or gra- nular; semi-transparent to opaque; lustre resinous ; sub-metallic or adamantine ; sometimes colourless, but usually grey, yellow, brown, or black ; streak light CASSITERITE. CASSITERITE, brown or greyish-white ; H. 6-7 ; G. 6 '8-7; some varieties with much iron 6-45. Var. 1. Diamond- tin is a miner's term for crystals when of considerable size ; 2. Sparable-tin occurs in small acute pyramids, almost acicular, like Figs. 65. 66. 3. Rosin-tin is reddish or yellowish, and semi-transparent. 4. Wood -tin or Fibrous-tin has a con- centric fibrous structure, colour various alternating shades of brown. 5. Toad's Eye Tin is a variety of wood tin, occurring in small spherical masses embedded in tin of a darker or lighter tint. 6. Stream-tin is found in rounded masses, as if waterworn, in many of the river gravels of Cornwall and Devon. 7. Mine-tin is that which occurs dis- seminated through, or in veins traversing, granite or clay slate. .B., etc. In matrass unchanged, or de- crepitates only ; on C the same, loses colour, or is reduced where it touches the charcoal ; with soda and KCy is readily reduced to a white malleable bead of Su in R F ; insoluble in HC1, HNO 3 , or Aqua Regia. Comp. Anhydrous stannic oxide, with sometimes as much as 10 per cent, of the oxides of iron or manganese. The following are analyses of Cornish specimens : a. b. c. d. Oxide of tin ... 98 "93 96 "26 91 -0 94 '5 Peroxide of iron & manganese 0'32 3 '40 9'0 1/5 Silica 075 0'75 1/0 Alumina 3'0 Totals ... 100-00 100'41 100 '0 100 '0 a. was a specimen from Altarnun, ana- lysed by Klaproth ; b. was analysed by Thomson, c. by Vauquelin (the sp. gr. was 6 '45), and d. by Johns. With tin 78-67 and oxygen 21 '33 the formula will be Sn or SnO a . ^ The following percentages of metallic tin were obtained by means of a charcoal crucible and blast furnace, by Klaproth, viz.: Light brown acicular crystals 75 per cent. Grey crystals from St. Agnes 74 do. Wood-tin 73 do. Stream-tin from La- dock 76 do. Stream-tin from Altar- nun 76 do. From which it appears that the stream- tin is even more pure than the grey or light brown crystals from the mines. Loc. a. Fine crystal shave been obtained from Botallack, Huel Owles, and other St. Just mines (Fig. 65) ; the cliffs north of St. Just ; Wherry Mine, near Pen- zance, in the cavities of a chloritic con- glomerate, cemented with amorphous cassiterite ; St. Michael's Mount, in the joints of the granite, with schorl, fluor, wolfram, and occasionally topaz, garnet, and beryl; Huel Providence and other mines near St Ives and Lelant ; Great Work, Huel Vor, Huel Metal, Great Huel Fortune, and other mines in Breage ; East Huel Lovell, Trumpet Consols, and other Wendron mines ; Huel Tremayne, and other Gwinear mines, in large macles (Figs. 69 and 70); Dolcoath, and other Camborne mines (Figs. 65, 66); Relistian (Fig. 62); East Pool ; Huel Uny ; Pednan- drea (Figs. 61, 62, and other forms, some- times associated with chalcedony); the United and other mines in Gwennap ; Tre- vaunance, Polberrow Consols, Huel Tow- an, Huel Pye, Pell Mine (Figs. 61, 62), Huel Kitty, and most of the St. Agnes mines ; Cligga Head ; Beam Mine, Polgooth, Stenna Gwynn, Goonbarrow, Minear Downs, and other mines near St. Austell ; Burthy Mine, St. Enoder, in small black crystals (Fig. 61) with native copper ; Huel Maudlin (Fig. 62), Kit Hill, Callington, in fine black crystals ; Drakewalls ; Ash burton ; Birch Tor ; Yeoland Consols ; Buckland Monacho- rum ; Huel Sidney, Plympton ; Rix Hill, near Tavistock ; Chagford in granite at the Morley clay works; Plympton; in the granite of Dartmoor ; as well as other places in Devonshire. b. Sparable-tin (Figs. 65, 66) has been found in fine crystals at Dolcoath ; Huel Uny; Pednandrea; Huel Park, St. Agnes ; Huel Owles, St. Just ; and many other mines ; in the granite of St. Michael's Mount, &c. c. Wood -tin has occurred at Polberrow Consols; Sancreed, in thick mam millary concretions capping quartz ; Huel Garth, near Penzance ; Great Huel Vor, Breage ; and many of the Cornish stream works. d. Toad's Eye Tin has been found in large masses at Tregurthy Moor and Gavrig- gan, embedded in quartz. e. Stream-tin has been f oun d in Carnon and other branches of Falmouth Har- bour, in large quantities ; also at Gwen- nap ; Trewarda, Kenwyn ; Ladock ; Al- tarnun ; Luxulian ; Lanlivery ; Fore Moors, St. Columb ; Bodmin Moor ; Tre- sowes, near Ashton in Breage ; St. Bu- ry an ; Holm Bridge, three miles N.W. of Buckfastleigh ; Sigford and Yarnour Wood, near Ilsington ; Warren Tor ; CASSITERITE. CELESTITE. 25 Monk's Hill, Plaster Down, near Samp- nird Spiney ; Axtown ; the Teign, the Bovey, West Dart, and many other streams in the "Western part of Devon- shire. Cassiterite has also been found in France, Spain, Germany, Sweden, Finland, Greenland, the United States, Mexico, Chili, Peru, Sumatra, Banca, Australia, &c. Large pseudomorphous crystals of cas- siterite after felspar occurred formerly inconsiderable abundance at HuelCoates, St. Agnes, some were like Fig. 179, but more compressed, others were macled. Many of the larger crystals "presented the curious circumstance of shewing the original felspar replaced by oxide of tin only about half across longitudinally." Similar pseudomorphs have been found at Carn Brecon, St. Mewan, near St. Austell; and also, about ten years ago, at Balleswidden, St. Just, by Mr. Richard Pearce. The silicate of tin described by J. Garby is, perhaps, a pseudomorph after quartz. Some occurred about 1820 as an impalpable powder, or compact; yellow- ish-grey in color, and composed of 53*0 per cent, of oxide of tin and 46 per cent, of silica According to Mr. J. Mich ell, some of the " silicate of tin was in hex- agonal prisms, much like quartz, but with the summits always wanting." Obs, The English crystals of cassi- terite are usually small and ^bright ; foreign crystals are often large and dull. Most of the tin stream works have yielded small quantities of gold from time to time. Wood-tin is said by Messrs. Greg and Lbttsom to have been found about the year 1858 " in walls by the roadside, in fragments nearly as large as a man's head, the surface water- worn frequently, and often exhibiting that peculiar distribution of colour in superimposed bands of various shades of brown and yellow, from which this variety derives its trivial name." Cassiterite is usually found in veins traversing granitic, schistose, or porphy- ritic rocks, and associated with quartz, fluor, schorl, chlorite, wolfram, mis- pickel, oxides of iron, pyrites, blende, and ores of lead and copper. It is harder and has a much lighter streak than wolfram, and has no cleavage, which in wolfram is always a well marked character. It is much harder than blende, and much heavier than garnet, schorl, or idocrase. Figs. 61 to 71 and Fig. 77 are all Cornish and Devon- shire forms. Macles are commonly joined by the face e ; the faces 1, k, r, Ji, M, O are often rough or uneven ; a and e are sometimes striated parallel to their intersections with each other. M is also sometimes striated. Angles. M M = 90 00' M z = 155 00' OM 90 00 Oz 112 25 a a 90 00 ss 121 40 My 119 43 ss' 87 07 M s 133 34 k k 163 00 M i 157 11 e e' 67 50 Ml 175 10 zz' 118 18 M k 171 30 z z 159 06 Me 113 15 Mr 168 41 Ma 135 00 CELESTITE. [Celestine.] Rhombic ; the crystals much resembling those of Barytes and Anglesite ; often in tabular crystals, much like Figs. 130, 131, 132 ; some planes striated or rough; perfect basal cleavage parallel to O, less perfect cleav- ages parallel to M and M' ; also compact, massive, fibrous, granular, earthy ; brit- tle ; fracture imperfectly conchoidal or uneven ; transparent to translucent ; vitreous to pearly ; colourless, or white, grey, bluish, or reddish ; sometimes pleochroic ; streak white ; H. 3-3 '5 ; G. 3 '8-4; pyrophosphoric. E., etc. In matrass often decrepitates; on C fuses at 3 to a white pearly bead, colouring the flame carmine red, espe- cially after being exposed to the R F and then treated with HC1 ; with soda melts, and sinks into the charcoal ; with borax melts to a clear glass, which is opaque and yellowish or brownish when cold; insoluble in acids ; soluble in HC1 after exposure to the R F, the solution mixed with alcohol burns with a bright red flame. Comp. Anhydrous sulphate of Strou- tia. No analysis of a specimen from the West of England is known, but foreign varieties contain from 40 to 46 per cent, of sulphuric anhydride, and 51 to 58 per cent, of strontia. With 43 '6 of sulphuric anhydride, and 56 '4 of strontia the for- mula will be SrS or SrSO^ or SO 2 Sro". Loc. Binner Down Mine, four miles north of Helston ; Sidmouth, and other places on the south coast of Devonshire, in fissures of the cliffs, in thin crystalline transparent plates on gypsum, and in the cavities of flints ; also Somersetshire, Gloucestershire, Yorkshire, Northum- berland, Wales, Scotland, France, Spain, Italy, Germany, Hungary, North Ameri- ca, &c. Obs. The name celestite is derived from coalestis sky blue this colour is not, however, characteristic of the species, 26 CELLULAR CERVANTITE. but in some instances at least is due to the presence of a minute proportion of phosphate of iron. A ngles. P M = 90 00' P d = 140 35' PM' 90 OC Po 127 56 MM' 104 02 PI 151 17 Cellular. When a mineral is full of small cavities or hollows it is termed "cellular; if the cavities are somewhat spherical, the term "vesicular" is used. Sometimes these hollows are large, and filled with matter of a different kind and colour, giving rise to the "amygda- loidal " structure. Pumice and Calamine are often cellular. Cellular Pyrites. A cellular variety of bisulphide of iron, usually of marca- site. CERUSSITE. [White Lead Ore.] Rhombic; in prisms ; often acicular and laterally ag- gregated ; sometimes stellate or tabular (Figs. 140, 141, 142); sometimes a dis- tinct cleavage parallel to M, the face a. usually striated, O rough ; sometimes massive, compact, fibrous, or earthy ; brittle ; fracture conchoidal or uneven ; transparent to translucent; with power- ful double refraction ; lustre resinous, adamantine, or pearly ; colourless, white, grey, greenish, or bluish, from the pre- sence of a trace of copper, or sometimes with a dark brown or black tarnish ; streak white ; H. 3-3 '5 ; G. 6 '4-6 '5. B., etc. In matrass decrepitates, turns yellow, and at a high temperature red, but becomes yellow again on cooling, sometimes phosphoresces ; on C decre- pitates, fuses at 1, and is readily reduced to a malleable bead of metallic lead, depositing a yellow incrustation on the charcoal; insoluble in HC1, but readily soluble in dilute HNO 3 , with efferves- cence. Gomp. Anhydrous carbonate of lead. No analysis of a specimen from the West of England is published. Foreign specimens are often pure. With oxide of lead 83 '5, and carbonic anhydride 16'5 the formula will be PbC or PbCO 3 or COPbo". Loc. Pentire Glaze and St. Minver, in very thin snow-white tables (some of the crystals from Pentire Glaze were 10 inches long), and in fine needles ; Huel Rose and Huel Penrose, near Helston, in delicate acicular prisms on Limonite ; Huel Alfred ; Huel Golden ; Huel Ann ; Great Retalkck, West Chiverton, and other mines in Perranzabuloe ; Huel Ptose, Newlyn ; Huel Confidence ; Huel Crenver ; Huel Primrose and Park Mat- thews, near St. Austell ; East Tamar, in fine colorless crystals, with Anglesite, in decomposed galena ; Hennock, near Chudleigh, in small acicular crystals ; Beeralston ; also Derbyshire, and other parts of England ; Scotland, Wales, Ire- land, France, Tyrol, Poland, Siberia, United States, &c. Obs. It may be readily distinguished from all minerals that at all resemble it by its ready effervescence with dilute HNO 3 and its easy reduction on charcoal. Angles. M M = 117 31' O y = 149 21' MO 90 00 pp 130 00 Ob 90 00 pp' 108 98 ab 90 00 kk 71 44 Ma 121 24 ii 110 40 Mi 145 20 ar 151 22 Mk 125 52 ai 145 10 CERVANTITE. [Antimonial ochre in part.] Rhombic (?) in acicular crystallizations ; also earthy, pulverulent, investing, massive, or dis- seminated ; brittle or friable ; opaque ; lustre greasy or pearly, glimmering or dull ; yellowish or reddish-white to yel- low ; streak the same, but usually lighter, and shining ; soft and friable"; (Dana says H. 4-5 ;) G. 4-4 1. B. , etc. In matrass gives a little water, and with a strong heat a faint white sub- limate ; on C is easily reduced to a grey brittle bead of antimony, coating the charcoal with white, and tinging the oxidising flame green ; soluble in HC1, the solution is sometimes partly precipi- tated by the addition of water. Gomp. Anhydrous binoxide of anti- mony, or else a mixture of antimonious and antimonic oxides. No analysis of a British specimen is known, but foreign specimens contain from 67 to 79 per cent. of antimony, and 16 to 20 of oxygen, with generally a little water of absorp- tion. With antimony 79 '2 and oxygen 20'8 the composition will be Sb or SboO, + Sb 2 5 - Loc. Near St. Minvers ; Huel Lea, on the Tamar ; Huel Kine ; Huel Boys, near Padstow ; Port Isaac ; Endellion ; Trevinnock ; Swanpool, near Falmouth ; also France, Spain, Germany, Hungary, Mexico, &c. Obs. It usually accompanies ores of antimony, and is sometimes pseudomor- phous after antimonite. Chalcedony. See Calcedony. CHALCOCITE. GHALCOPHYLLITE. 27 CHALCOCITE. [Chalcosine. Copper Glance, R*ed- ruthite. Vitreous Copper.] Rhombic ; in regular six-sided prisms, usually short and modified terminally ; also obtuse six-sided pyramids ; often macled, with the face O striated (Figs. 100 to 107); usually massive, lamellar, or compact ; sectile or almost malleable ; fracture conchoidal, even, or uneven ; opaque ; lustre metallic, brilliant to glimmering ; blackish lead-grey, often a black or iri- descent tarnish, or coated with green carbonate ; streak greyish-black ; H. 2-5-3; G. 5-5-5-8. Var. Nail-headed eopper ore is a macled variety (Fig. 104), so called from its resemblance to the heads of some nails. B., etc. In matrass gives a slight white sublimate ; on C fuses at 1, tinges the flame blue, gives off vapours of sul- phurous anhydride, and emits sparks ; with soda or alternate OF and RF yields a bead of metallic copper, leaving usually a little black infusible magnetic slag ; decomposed by HNOs. Gomp. Anhydrous subsulphide of copper. The following is an analysis of a specimen from the United Mines, Gwennap, by Thomson : Copper 7716 Sulphur 20-62 Iron 1-45 Total 99-23 With copper 79 '8 and sulphur 20 '2 the formula will be Cu 2 S. LOG. Fine crystals, formerly at Levant (Figs. 100, 102); Botallack (Fig. 102); St. Ives Consols, in very fine crystals, lately like Figs. 104, 107, 108 ; Huel Crenver ; Huel Abraham, in thin hexagonal plates, nail-headed copper, arborescent, and most of the forms 100 to 106 ; Camborne Vean; Cook's Kitchen (Fig. 116); Dol- coath, iridescent; Huel Fanny and North Huel Basset, in fine elongated and very perfect crystals ; Huel Buller and other mines. Massive at most of the copper mines in Cornwall, especially Botallack, Spearn Moor, Levant, Ding Dong, Huel Neptune, and in an elvan course near Polgooth; Huel Betsy and other mines in Devonshire, in small quantities ; also Yorkshire, Scotland, Ireland, Norway, Sweden, Germany, Siberia, North and South America, &c. Obs. It may be distinguished from Fahlerz by its sectility and grey streak ; from galena by the absence of cleavage and sectility ; from pyrargyrite by jits streak ; from argentite by its blowpipe reactions ; from Bournonite by its sec- tility ; and from fntimonite by its blow- pipe reactions. All the Figs, from 100 to 107 represent forms which have oc- curred in Cornwall or Devon. Angles. O M = 90 00' Op- 117 24' Ob 90 00 MM' 119 35 Oa 90 00 dd' 125 38 Od 117 16 PP 126 54 O e 147 06 pa 116 32 Oz 147 16 Ma 120 12 Ov 136 03 Chalcolite. See Torbernite. CHALCOPHYLLITE. [Tamarite. Copper Mica. Rhom- boidal Arseniate of Copper.] Hexago- nal, in thin tables, like Fig. 201, with perfect cleavage parallel to O, or foliated masses, or druses ; sectile, flexible ; trans- parent to translucent; lustre adaman- tine, vitreous, or pearly ; various shades of green ; streak light green ; H. 2 ; G. 2-4-2-7. B.i etc. In matrass decrepitates, yields much water, turns dark green to black, and with a strong heat deposits a white or straw-coloured sublimate ; on C decrepitates, turns black, colours the flame blue or greenish, melts to a white globule of metallic appearance; with RF yields a strong garlic odour ; with soda a bead of copper ; soluble in HNO 3 , and partially in ammonia. Comp. Hydrated arseniate of copper and alumina. The following are analyses of speci- mens from Cornwall, some, probably all, from Huel Gorland : a. b. c. d. e. Oxide of Cop- per 58-00 52-92 52-30 4676 45 '51 Arsenic an- hydride .. 21-00 19-35 21-27 15 '49 15 '58 Alumina.... 1'80 213 5 '69 6 '25 Oxide of iron 0'60 0'61 Phosphoric anhydride. 1'29 1-66 Water 21'0023-9422-58 31 '46 32 '05 Totals . . 100-00 99-30 99 '84 100 '00 100 '00 Sp. Gr.. 2-54 2 '659 2 -659 2 '44 2 "44 a. was analysed by Chenevix ; b. and c. by Damour; d. and e. are recent and very careful analyses by Church. With oxide of copper 58 "8, arsenic anhydride 21*2, and water 20'0 the formula may be written 8CuAs 2 +12H 2 or 3CuO, As 2 O 5 + 5CuH 2 Oo + 7H 2 O or As 2 O 2 Cuo" 3 + 5CuHo 2 + 7OH 2 ; this agiees pretty well with the analysis of Chenevix. With oxide of copper 53 "6, arsenic anhydride 23 "1, and water 24 '3 it may be 8CuAs 2 + 14H 2 28 CHALCOPYEITE. CHALCOPYEITE. or 3CuO As 2 O g + 5CuH 2 O 2 + 9H.,O or As 2 O 2 Cuo" 3 +5CuHo 2 + 9OH 2 ; this agrees somewhat more nearly with the analyses of Damour. With oxide of copper 45 '39, alumina 7 '35, arsenic anhydride 16 '42, and water 30 '84 the formula may be SCuAloAso 24H 2 or Cu 3 (AsO 4 ) 2 5H 2 O + 5CuH 2 O 2 + A1oH 6 O 6 or As 2 O 2 Cuo" 3 + 5Cu Ho 2 + Al 2 Ho 6 + 50H 2 . WitlToxide of copper 44 '82, alumina 7 '26, arsenic an- hydride 16 '21, and water 31 '71 the for- mula may be 8CuAl 2 Aso25H 2 or Cu 3 (AsO 4 ) 2 6H 2 O + 5CuH 2 O 2 + A1 2 H 6 O 6 or As 2 O 2 Cuo" 3 + 5CuHo 2 + Al 2 Ho 6 + 6OH 2 . Both these formulse agree very closely with the analyses of Professor Church, and either of them may be taken as the correct one, since they only differ by one equivalent of water. Nearly half the water may be separated by drying in vacuo (hygroscopic moisture), while the rest is not driven off at 100C (com- bined water). LOG. Huel Gorland, Huel Muttrell, Huel Unity, Ting Tang, and other mines in Gwennap, but not recently ; Huel Tamar (whence Brooke and Miller's name of Tamarite), Gunnislake ; also Germany and Hungary. 06s. Specimens may, perhaps, be ob- tained by carefully turning over the old burrows in copper mining districts. "The specimens which have been ob- tained lately are not so well crystallized as those which were raised formerly, neither do they equal them in colour : being of a pale verdigris green." (Greg and Lettsom, p. 316, 1858.) Chalcophyllite occurs associated with other ores of copper, and is sometimes altered to Chrysocolla. It may be dis- tinguished from Torbernite by its strong arsenical blowpipe reactions. A ngles. R R' = 110 12' e o = 124 09> R' o 108 44 v o 124 09 v truncates the edge R' o. CHALCOPYRITE. [Towanite. Copper Pyrites. Yellow Copper Ore.] Pyramidal ; in more or less modified sphenoids, with e. p. striated, rough, or uneven ; the sphenoid is very near a tetrahedron : often macled (Pigs. 79 to 85) ; also stalactitic, botryoidal, or mammilated ; usually massive, compact, lamellar, ordisseminate ; britfcleor almost sectile ; fracture conchoidal or uneven ; opaque ; lustre metallic, brilliant to glim- mering ; brass yellow, often with an iridescent tarnish ; streak greenish- black ; scratch, bright yellow and shin- ing; H. 3-5-4; G. 4 1-4 "3. Var. Blistered copper is a botryoidal variety ; peacock copper is a massive variety, with blue, red, green, brown, or iridescent tarnish, and often a lamellar structure. B , etc. In matrass sometimes decre- pitates, gives a yellow sublimate ; on C melts to a black brittle magnetic glo- bule ; with soda and a little borax in R F gives a bead of copper ; decomposed by HC1, forming a green solution and leaving yellowish powdery sulphur. Comp. Sulphide of copper and iron. The following are analyses of Cornish specimens : a, b. c. d. Copper 30-00 31 '20 3015 30 '00 Iron 32-20 30'80 32'37 31 '00 ! Sulphur ... 3516 34 "46 35 '34 33 '00 Silica 2'64 110 3'00 Lead, arse- nic, loss, &c. 2-44 214 300 Totals ... 100 00 lOO'OO 100 '00 100 '00 a., b., c were analysed by Phillips, a. and c. being crystallized, b. botryoidal; d. was a specimen from Huel Towan, analysed by Michell. With sulphur 34 '9, copper 34 '6, and iron 30'5 the formula may be written Cu 2 S + Fe 2 S 3 or Cu 2 S + FeSfFeS 2 or CuFeS*. Loc. Crystallized, East Pool, with cha- lybite, in sphenoids scarcely distinguish- able from Fig. 33 ; Cam Brea. iridescent, on cubes of fluor ; Tincroft ; Dolcoath ; Huel Tolgus, in obtuse rhomboids (pseu- domorphous after dolomite?) ; Huel Bul- ler, in very perfect sphenoids of one inch or more ; Huel Towan, St. Agnes ; Alfred Consols, Hayle, in very perfect rhombic dodecahedrons (Greg and Lett- som, 340), perhaps pseudomorphous after blende or erubescite ; St. Just, in fine curved rhomboids (pseudomorphous after dolomite?); Levant Mine, pseudomor- phous after Fahlerz ; Herodsfoot, in double pyramids of three-quarters of an inch ; Virtuous Lady Mine, in beauti- fully iridescent and large sphenoids ; Ashburton ; Huel Franco ; Buckland Monachorum ; Huel Robert ; Sampford Spiney ; Devon and Courtenay ; Devon Great Consols ; Huel Friendship; Wills- worthy Mines ; Copper Hill, Fursdon j Manor, and other mines near Okeharnp- ' ton ; Combemartin, North Moulton, Molland, Lundy Island, &c. ; and other copper mines in the two counties. Blistered Copper Ore.- Cook's Kit- chen ; Huel Basset ; Dolcoath ; Ale and Cakes ; and other localities. Massive and Iridescent (Peacock Cop- per Ore). The United Mines, Gwen- nap ; Gunnislake ; Great Criunis ; South CHALCOSINE. CHALYBITE. 29 Caradon ; Virtuous Lady ; Devon Great Consols, and many other mines, often associated with chalybite, blende, and cassiterite; also Cumberland, and several other English counties ; Wales, Scot- land, Ireland, Germany, Italy, Spain, Siberia, the United States, South America, Africa, Australia, &c. obs. It may readily be distinguished from pyrites and marcasite by its infe- rior hardness, from erubescite by its yellow scratch ; from gold by its brittle- ness. A variety is described b/ Mr. John Garby as occurring near Gwinear "fine- grained, white streak, pale yellow colour, 20 per cent, only of copper, and sufficient silver to pay for extraction." Another white variety from Huel Gorland, in Gwennap, yielded 40'0of copper, besides iron, arsenic, and sulphur ; it occurred with ordinary chalcopyrite. Angles. P P = 70 07' a a = 90 00' PP' 109 53 cd 140 47 PC 125 40 ex 155 05 Pa 125 03 cv 152 33 P z 140 20 c z 116 54 PI 144 20 zz 101 50 me 90 00 vx 148 06 Chalcosine. See Chalcocite. Chalcotrichite. See Cuprite. CHALYBITE. [Siderite. Spathose Iron.] Hexagonal, in small obtuse or acute rhombohedrons, or lenticular, occasionally in hexagonal prisms (Figs. 195, 199, 202, 217, 220, 221, 224, 225, 231), often macled; cleavage rhombohedral, (R) perfect, often curved ; some of the faces striated, rough, un- even, or curved ; also massive, granular, lamellar, or compact ; sometimes reni- form or botryoidal ; brittle ; fracture subconchoidal or uneven ; translucent to opaque; lustre adamantine, pearly, or silky, brilliant to glimmering ; yellowish- white to dark-brown ; often a dark tar- nish from exposure to light; streak white, yellowish, or brownish; H. 3'5- 4'5; G. 3 -7-3*9; sometimes feebly mag- netic. Var. Wood Iron is a fibrous variety, of brownish colour and silky lustre. Sphaerosiderite is a nodular, concre- tionary variety. Slipper Iron is a pseudomorphous variety, which occurs in forms somewhat resembling a lady's slipper. Clay Iron-stone is an argillaceous mas- sive variety, rather a rock than a mineral. Black Band is the same, but with a considerable mixture of carbonaceous matter. B., etc. In matrass turns very dark and magnetic ; on C the same ; infusible ; with borax or micro, gives Fe reactions ; the powder is slowly soluble with effer- vescence in HC1 or HNO 3 . Comp. Anhydrous carbonateof iron, with often a part of the iron replaced by Mn or Ca. No analysis of a specimen from the West of England is known, but a specimen from Durham gave Oxide of iron 54 '57, oxide of manganese 151, lime 318, carbonic anhydride 35 '90. With oxide of iron 621 and carbonic an- hydride 37 '9, the formula would be FeC or FeCO 3 or COFeo". Loc. Fine crystals at Huel Maudlin, near Lostwithiel (Figs. 195 and 202), also pseudomorphous after fluor; Huel Boul- ton, in six-sided prisms ; Charlestown United, and other mines near St. Aus- tell, very perfect and iridescent ; Crinnis Mine, with drusy childrenite ; Fowey Consols, in forms approaching to the octahedron (Fig. 224), tabular (Fig. 202), and crystals like Fig. 221, rich brown, translucent, and the faces slightly curved ; near Bodmin, in hexagonal crys- tals, more than one inch long, like Fig. 195, attached to quartz ; Bucker's Mine (Fig. 217) ; Dolcoath ; Cook's Kitchen, East Pool and other mines in the neighbour- hood of Camborne, and many other mines in Cornwall and Devon ; Carny worth and Huel Owles (Fig. 220 and other forms); Botallack, in brown rhomboids, like Fig. 119 ; Virtuous Lady, Huel Betsy, Huel Crebor, and Bedford United Mines, in fine spheroidal groups, made up of curved tabular crystals, of a rich hair-brown colour ; Ivy Bridge, on quartz ; Beeral- stone, lenticular. Wood Iron. East Pool, Tincroft, Cook's Kitchen, Huel Buller, Huel Beau- champ, and other mines near Camborne and Kedruth ; East Crinnis, and other mines near St. Austell. Sphaerosiderite. Madron, near Pen- zance, and Mount Mine, near Marazion, in botryoidal masses resembling calamine. Massive and compact. HuelKose and Huel Penrose near Helston ; at Perran- zabuloe ; at the railway cutting near Plympton, of a beautiful white colour ; Exmpor, and Combemartin, and other localities in the two counties ; also many parts of England, Scotland, Wales, Ire- land, Fra'nce, Spain, Italy, Germany, Poland, United States, South Ame- rica, &c. Pseudomorphs. The "Slipper Iron" found at Virtuous Lady, Bseralstone, and Huel Friendship is probably pseudo- morphous after selenite. At Virtuous Lady hollow cubes of chalybite are also 30 CHENEVIXITE. CHESSYLITR found, from a very small size to three or four inches square ; these are probably casts of fluor. In the interior f these " boxes," as they are called by the miners, fine crystals of chalcopyrite are sometimes found, together with beautiful froups of opaque white quartz crystals. n one instance this peculiar form of chalybite has been observed as a coating to a cube of fiuor. At Beeralstone the chalybite occurs pseudomorphous after calcite. A specimen of chalybite, almost che- mically pure, was found by Mr. Wm. Vicary in the interior of a large flint near Haldon. It was a globular crystal- line mass, of radiated structure and yellowish-grey colour. Obs. Chalybite may be distinguished from childrenite by its inferior hardness, different crystalline form, and usually the absence of any reactions for phosphoric acid before the blowpipe ; from calcite and dolomite by its becoming black and magnetic when heated in a matrass. The massive varieties often contain some phosphoric acid. Angles. RR = 107 00' bb' = 120 00' Ro 136 37 w 144 56 ee 136 34 v v' 105 15 mm 66 18 v v" 134 40 ss 64 10 vo 121 25 so 101 57 ba 150 00 oe 154 43 Rv 150 45 o m 104 49 f f 80 06 oa 90 00 ou 163 00 a a' 120 00 of 117 53 f is a rhombohedron of 80 06', and truncates the angle e' a ; u forms a rhom- bohedron of about 120 and truncates ss. Besides Figs. 195, 199, 202, 217, 220, 221, 224, 225, 231, the following forms and combinations have all been found in Cornwall or Devon, viz., f, s, fa, a o, R o, R a O, R m f , R o u, Rose, Raose, Raoe, Rsb, Rv, Rvb, Raofe. Chemical Characters of Minerals. Those which depend upon their chemi- cal composition, as taste, odour, solubi- lity, fusibility, and the reactions with soda, borax, and micro. Chemical Equivalents. See Table of the Elements in part 1. CHENEVIXITE. Massive ; compact ; opaque ; vitreous ; dark dull green, passing into yellow; streak yellowish-green: H. 4 '5: G. 3-93 (?) B., etc. In matrass decrepitates, gives off water, and turns brown ; on fuses easily to a black magnetic scoria, giving off arsenical fumes; easily soluble in HC1 or HN0 3 . Comp. Hydrated arseniate of iron and copper. Analyses : a, b. Arsenic anhydride 33 '50 ... 32 '20 Oxide of copper 22'50 ... 3170 Oxide of iron 27 '50 ... 2510 Phosphoric anhydride... ... 2 '30 Lime ... 0'34 Water 12'00 ... 8'66 Totals 95-50 ... 100'30 Both were Cornish specimens, a. was ana- lysed by Chenevix, b. by Adam, recently. With arsenic an hydride 34 '2, oxide of cop- per 29-9, oxide of iron 26 '9, and water 9'0 the formula may be written 2As 2 5Cu5Fe 8H 2 or (As 2 O 2 ) 2 Cuo" 3 Feo" 3 + CuHo 2 FeHo 2 + 4OH 2 or 3CuOAs 2 O 5 + 2CuH 2 O 2 =3FeO As a O 5 + FeH 2 O a + 4H 2 O. Loc. Cornwall, in small compact masses, so imbedded in quartz rock that it is not possible to separate them com- pletely. Obs. Probably specimens might be found by a careful examination of old collections. Chenocoproiite. See Pitticite. GHESSYLITE. [Azurite. Lazulite. Blue Malachite. Blue Copper.] Oblique ; crystals usu- ally small and short prismatic or tabular (Fig. 154), with striated or rough faces ; also botryoidal, stalactitic, in- vesting, disseminate, massive, compact, earthy ; brittle ; fracture conchoidal, uneven, or splintery ; vitreous to adaman- tine ; deep blue ; streak blue, lighter than color; H. 35-4 ; G. 3'5-3'8. B., etc. In matrass decrepitates, turns black, and gives off water ; on C fuses and yields a bead of copper; soluble with effervescence in HC1 or HNO 3 , more slowly in ammonia. Comp. Hydrated carbonate of copper. No analysis of a British specimen is pub- lished, but a specimen from Chessy yielded Oxide of copper 69 '09, carbonic anhydride 25 69, water 5 '22, which agrees with the formula? 3Cu, 2C, H 2 or 2CuCO 3 -f CuH 2 O 3 or 2COCuo" + CuHo 2 . Loc. Huel Gorland, Huel Unity, Huel Virgin, Ting Tang (prettily crys- tallized), Carharrack, all in Gwennap ; Huel Muttrell, Huel Mill Pool (once, crystallized); Huel Buller, near Red- ruth (Fig. 154 and P s h 1 the faces h predominating); and in small quantity in most of the Cornish copper mines; CHILDRENITE. CHLOEITR 31 East Tamar, near Beerferris, in good crystals ; Devon Great Consols, and other copper mines in Devon ; also at Chessy, near Lyons, where the best crystals have been obtained ; Thu- ringia, Moldavia, Ural, Siberia, United States, &c. Obs. Chessylite is usually found lining cavities in the older rocks, with malachite and cuprite. It is, perhaps, a decomposition product. When abundant it is ground up for use as a pigment. A ngles. MM = 99 32' P h ~ 111 46' M0 57 11 PM 91 48 11 119 16 P0 132 50 hh 106 14 Ps 135 13 The more common British forms are Phi, Phis, and Fig. 154. Chiastolite. See Andalusite. CHILDRENITE. [Rhombic ; in small modified pyra- mids, like Fig. 146, or tabular crystals, like Figs. 143, 144, 145 ; or druses; frac- ture uueven ; translucent ; vitreous to resinous, brilliant ; yellowish or brown- ish ; streak pale yellowish-brown ; H. 4'5-S; G. 3'2. B., etc. In matrass gives off water, which does not usually affect test paper; on C is infusible, or swells up and fuses on the edges to a dark mass, and colours the flame bluish-green ; with borax and micro, gives the Fe and Mn reactions ; the powder slowly soluble in HC1. Comp. Hydfated phosphate of iron, alumina, and manganese, as appears from the following analysis of a Cornish specimen by Rammelsberg ; Phosphoric anhydride 28 *92 Alumina 14'44 Oxide of iron 30'68 Oxide of manganese 9'07 Magnesia 0'14 Water .., 16 '98 Total 100-23 With oxide of iron 29 '3, oxide of manga- nese 9 '6, alumina 14 '0, phosphoric anhy- dride 29'1, and water 18 '0 the formula may be 6Fe 2Mn 2A1 2 3P 2 '-!-15H 2 O or P 3 O(Al 2 o vi ) 2 Fep" 6 Mno" 2 + 15OH 2 . LOG. Crinnis Mine, near St. Austell, on slate, sometimes with apatite, in small distinct crystals, like Fig. 146 ; Huel Cre- bor, in distinct crystals, like Fig. 143, em- bedded in greyish -green chloritic earth ; George and Charlotte Mine, Tavistock, in large and brilliant crystals, like Fig. 145, some one inch in length, on quartz, chalybite, and pyrites j Devon and Corn- wall United Mines. It occurs also in Cumberland and the United States. Obs. It may be mistaken for chaly- bite, but may be distinguished by its crystalline form and superior hardness. Angles. O r =* 109 53' s s' = 130* 04' Os 114 58 ss 102 41 On 142 07 nn' 75 46 Oa 152 22 rn 139 08 Oo 90 00 rs 168 29 rr' 119 32 sn 137 26 China Clay. See Kaolin. China Stone. This is a decomposed or imperfectly formed white granite, abund- ant in the neighbourhood of St. Austell, Breage, St. Day, and other places in Cornwall. It is used for making the finer kinds of pottery. Chloanthite. See Smaltite. Chloride of Silver. See Kerate. Chloride of Sodium. See Halite. Chlorides. Salts composed of a metal in union with chlorine. All the chlorides, except those of silver, lead, and mer- cury, are readily soluble in water, and have a distinct taste. From their solu- bility they are not common as minerals, with the exception of Rock Salt or Halite. The chlorides found in the two counties are Kerate, Botallackite, Halite, Tallingite, A tacamite, Cromfordite^ Cromfordite is a chloro-carbonate. Ata- camite is an oxy-chloride. CHLORITE. [Prochlorite. Dana.] Hexagonal ; crystals very rare ; usually thin hexago- nal plates, often grouped together in rosettes ; cleavage basal, rery perfect j massive ; foliated, the f oliae flexible, but scarcely at all elastic ; generally scaly, compact, or earthy; investing, pseudo- morphous, or disseminated ; sectile ; fracture earthy or slaty ; unctuous ; semitransparent to opaque; lustre pearly or sub-metallic ; shining or dull ; various shades of green, sometimes blue, greyish, yellowish , or brown ; crystals dichroic ; streak white, or like the colour, but paler; H. 1-2; G. 2'7-3'0. B.j etc. In matrass gives off water, becomes lighter in colour ; on C fuses at 5 (?) to a magnetic mass, which, with borax and micro., gives iron reactions ; in the forceps glows with a bright light, but is scarcely fusible ; insoluble in HC1 or HNO 3 . Partly soluble in warm con- centrated H 2 SO 4 . Comp. Hydrous silicate of alumina, magnesia, and iron. No analysis of a 32 CHLOEOMELANE. CHONDRODITE. British specimen is published, but foreign specimens yield from 25 '0 to 28 '0 per cent, of silica, 14 '5 to 22'0 of alumina, 15'0 to 29-0 of oxide of iron, 13 '0 to 31 '0 magnesia, 90 to 14*0 of water. With silica 26'9, alumina 19 '8, oxide of iron 27 '6, magnesia 15 '3, water 10 '4 the for- mula may be 6Fe 6Mg 3A1 2 7Si 9H 2 (oxygen ratio for R R 2 Si H 2 =12 : 9 : 14 : 9. for bases and silica 3:2) or (4-7ths Mg Fe) 3 +(3-7ths Al 2 )Si+4-3rdsH 2 or Si 7 O 2 (Al 2 Ho 6 ) 3 Feo" ? Mgo" 6 . LOG Chlorite occurs in most of the tin mines of the two western counties. At Virtuous Lady Mine it often contains fine crystals of mispickel, and sometimes small crystals of anatase and brookite ; at Cam' Brea, Great Huel Vor, Huel Prospidnick, and other mines it contains beautiful striated cubes, and pentagonal dodecahedrons of pyrites disseminated through it ; at New Rosewarne, near Gwinear, it occurs in foliated and ra- diated masses, with quartz, killas, brec- cia, and sometimes cassiterite, and also in the form of a "cap" on quartz crys- tals. At Wherry Mine, near Penzance, a conglomerate of chlorite pebbles, ce- mented by oxide of tin, contained pure crystals of tin. In some of the mines near St. Day small crystals of fluor are found embedded in chlorite ; at Botal- lack it sometimes contains small parti- cles of cobaltite. It occurs pseudomor- phous after felspar in much of the gra- nite to the south and west of Carnmarth ; at the Consolidated Mines in the form of albite ; at North Roskear, in pseudomor- phous octahedrons, perhaps after fluor ; on Dartmoor and at St. Just, in the form of axinite ; at Tresavean, in octa- hedrons, perhaps after magnetite. It also occurs in Cumberland, Westmore- land, Wales, Scotland, Ireland, Ger- many, Tyrol, and most mining countries. O6. Chlorite often contains disse- minated crystals of pyrites, hornblende, magnetite, fluor, quartz, and sometimes garnet. In Cornwall it is known as "Peach," and is especially associated with cassiterite. Chlorocarbonate of Lead. See Crom- fordite. Chloromelane. See Cronstedtite. CHLOROPAL. [Nontronite. Pinguite. Gramenite.] Amorphous, massive, compact, opaline or earthy ; fragile ; fracture conchoidal, splintery, or earthy; opaque to sub- translucent ; resinous to dull ; green or yellowish-green ; H. to 4'5 ; G. 1'7-2'1. Var. 1. Chloropal. H. 2 '5-4 '5 ; meagre ; adherent ; brownish or yellow- ish-green. 2. Nontronite. H. 2 '5-4 '5; yellow or greenish ; unctuous. 3. Pinguite. H. 0-1 ; green ; non- adherent. 4. Gramenite. Fibrous or feathery, grass-green. -B., etc. In matrass gives off water and becomes darker ; on C infusible ; turns black and magnetic ; with borax and micro, gives the reactions for iron and silica. Chloropal is partly decomposed by HC1. Pinguite is completely decom- posed with separation of powdery silica. Nontronite is decomposed, and deposits gelatinous silica. Comp. Hydrated silicate of iron. No analysis of a British specimen is known to the author, but foreign specimens con- tain of silica 39 to 71 per cent. , peroxide of iron 38 '0, and water 19 '2, the formula may be written 2Fe 2 6Si + 9H 2 (oxygen ratio = 1 : 2) or Si 6 O 6 (Fe 2 ovi) 2 9OH 2 . Loc. Chloropal is abundant in a quarry at Carn Gray ; near Carclaze j Mine, St. Austell, of a greenish-brown colour, with fluor, in fissures of the de- composed granite; Tremearne, Breage (Pinguite ?); it is found also in Germany, Hungary, and Ceylon. Obs. Careful analyses of this mineral are much required. Chlorophane. See Fluor. CHONDRODITE. [Humite.] Rhombic ; in very small complex crystals, like 153 ; sometimes macled, usually in embedded grains or granular masses ; fracture sub-conchoidal or uneven ; transparent to nearly opaque ; vitreous or resinous ; white, yellow, brown, red, green, grey, black ; streak white or slightly yellow or grey : H. 6-6-5 ; G. 31-3-3. B. , etc. In matrass no change, or turns first darker and then white ; on C infu- sible, changes colour sometimes ; with micro, in the open tube gives the reaction for fluorine ; with borax or micro, yields iron reactions ; decomposed by HC1, yielding a deposit of gelatinous silica. Comp. Anhydrous silicate of magne- sia, containing some fluorine. No analy- sis of a British specimen is known. Foreign specimens yield from 32 '0 to 36 '0 per cent, of silica, 51 '0 to 60 '0 of mag- nesia, and 3'0 to 10 '0 of fluorine, which, perhaps, only replaces a part of the oxy- gen. With magnesia 64 '0 and silica 36 CHROMITE. CHRYSOCOLLA. 33 the formula might be 8Mg 3Si (oxygen ratio = 4 : 3) or with silica 35 3, magne- sia 60*0, and fluorine 7 '7 the formula may be Si 3 Mgo" ? (MgFO)j. LOG. It is said to have been found at Huel Druid, near Redruth ; it occurs also in Scotland, Ireland, Germany, Kussia, Canada, United States, &c. 06s. The crystals are usually very small, very much modified, and embedded in granular limestone, or granite, or vol- canic rocks. It more often occurs in rounded granular masses or very indis- tinct prisms. Fig. 153 represents a crys- tal of chondrodite from New Jersey. Angles. MM' = 85 00' dz = 136 dd' 112 zz' 127 Chromates. Salts composed of chromic anhydride, in combination with a metal- lic oxide ; or chromic acid in which the hydrogen is displaced by a metal. The chief mineral chromates are those of iron and lead (chromite and crocoisite). Of these only the first has been found in Cornwall or Devon. CHROMITE. [Chrome Iron Ore.] Cubical; in octa- hedrons (Fig. 1), with imperfect octahe- dral cleavage ; or massive ; more usually disseminated in grains ; fracture imper- fect conchoidal or uneven ; opaque ; lustre sub-metallic or resinous ; brownish- black ; streak yellowish to reddish-brown ; H. 5 '5; G. 4*4-4 '5; sometimes weakly magnetic. .B., etc. In matrass unchanged ; on C infusible, but becomes somewhat brown- er ; non-magnetic varieties become mag- netic when heated in R F ; with borax forms an emerald-green bead ; with micro, the same ; when fused with nitre a yellowish mass is formed, which pro- duces a yellow solution if dissolved in water ; scarcely affected by acids. Comp. Chromate and aluminate of iron. Foreign specimens contain from 36 '0 to 60 '0 per cent, of chromic per- oxide, 9'0 to 21 '0 per cent, of alumina, and 18 '0 to 37 per cent, of oxide of iron. The alumina is regarded as replacing a part of the chromic peroxide. The oxide of iron is also in some cases partly re- placed by magnesia. With 32 '0 per cent, of oxide of iron and 68 '0 of chromic per- oxide the formula may be written FeCr 2 or FeCr 2 O 4 or Cr 2 O 2 Feo". Loc. It was reported from the Lizard district many years ago, by Mr. Mich ell, of Calenick. It has been lately re-disco- vered in a quarry near Cadgwith, by Mr. Richard Pearce, F.G.S., of Swansea. The serpentine rock when analysed yielded an amount of chromic peroxide which was estimated as equal tol'3 per cent, of the whole. A portion of the chromite, me- chanically separated, yielded 30 '0 per cent, of chromic peroxide. Also in Scot- land, the Shetland Isles, France, Ger- many, Norway, United States, &c. Obs. Chromite is used in the prepara- tion of a considerable variety of pig- ments, as chrome-green, chrome-yellow, &c. It is usually found associated with serpentine rocks or in crystalline lime- stones. CHRYSOCOLLA. [Silicate of Copper. Siliceous Oxide of Copper.] Amorphous ; globular, stalac- titic, reniform ; massive, investing, dis- beminate, pseudomorphous ; brittle ; frac- ture conchoidal or splintery; translucent to neaxly opaque, resinous or wax>y ; shining to dull ; green or blue, sometimes brownish or almost white ; streak white or slightly greenish ; H. 2-3 ; G. 2 '2 to 2-3. B., etc. In matrass gives off water and turns black ; on infusible, blackens in O F, reddens in R F ; with soda yields a red malleable bead of copper ; with borax gives Cu reactions ; slowly soluble in HC1 without effervescence, forming a green solution and depositing gelatinous silica. Comp. Hydrated silicate of copper. No analysis of a British specimen is pub- lished, but foreign specimens contain from 26 '0 to 52 "0 per ceut. of Silica ; 27 '0 to 45*0 per cent, of oxide of copper, and 16 '0 to 31 "0 per cent, of water, besides small quantities of alumina, mag- nesia, lime, potash, and oxide of iron. With silica 34 '2, oxide of copper 45*3, and water 20 '5, the formula may be CuSi2H. 2 (oxygen ratio 1 : 2 : 2) or CuSiO 3 + 2H,O or SiOCuo" + 2OH 2 or tiiO a CuHo 3 + OH a . .Loc Huel Edward, St. Just, with aragonite ; many parts of the Lizard dis- trict, with native copper ; Ting Tang ; Huel Gorland; Huel Muttrell; Huel Unity; West Huel Jewel, and other mines near St. Day; Prince George Mine, Gwinear ; Huel Trannack ; Plioauix Mine ; Grunnislake ; and in most of the copper mines of the two counties in small quan- tities; also Cumberland, Westmoreland, Wales, Scotland, Ireland, Germany, Hungary, Italy, Siberia, North America, '"hill, Australia, &c. Obs. It may be readily distinguished from malai-hite by the absence of effer- vescence when treated with dilute HC1 ; 34 CHRYSOPRASE. CLINOCLASE. from atacamite by its insolubility in am- monia ; from the arseniates and phos- phates of copper by its infusibility. Pseuclomorphs after cuprite and mica have been found in Cornwall. Chrysoprase. See Calcedony. Chrysotile. A fibrous variety of ser- pentine much resembling asbestos. (See Serpentine.) CHURCHITE. Oblique? fan -like aggregations of mi- nute crystals, with one perfect and several less distinct cleavages ; also ra- diated and columnar ; brittle ; fracture conchoidal ; transparent to translucent ; vitreous, pearly on terminal planes ; pale smoke-grey tinged with flesh -red ; streak and powder white; H. 3, or a little above ; G. about 3 '14. B., etc. In matrass gives off water with an acid reaction, and becomes opaque ; on C becomes reddish in O F, but is infusible ; with borax in O F gives a bead which is orange yellow and opa- line while hot, colourless or slightly amethystine when cold. Gomp. It is a hydrated cerous phos- phate, as appears from the following analysis, the mean of several, made by Professor A. H. Church, of Ciren- cester : Phosphoric anhydride 28'48 Oxide of cerium 51 '87 Lime 5'42 Water 14'93 Total IOQ'70 "With 52 '7 of oxide of cerium, 5 '5 of lime, 27 '8 of phosphoric anhydride, and 14 '0 of water the formula may be writ- ten 5Ce, Ca, 2P 2 -f8H 2 (oxygen ratio 3 : 5 : 4) or (5-6ths Ce l-6th Ca) 3 P 2 + 4H 2 or P 4 O 4 Ceo" 5 Cao" + 8OH 2 . Professor Church also obtained a trace of fluorine, and Mr. C. G. Williams detected didy- mium by means of the spectroscope. Loc. It was discovered by Mr. Tailing, near Lostwithiel, in a copper lode, invest- ing quartz and killas, forming a coating of minute crystals about one-tenth of ; an inch thick. Professor Church has since detected it in several Cornish apatites from different localities. Ob. The cleavage is supposed to be basal by Mr. N. S. Maskelyne, but clino- diagonal by Dana. This is the first British mineral which has been found to contain cerium. It is well known that didymium is usually found in minerals containing cerium, and it is interesting to find that this is no exception to the rule, although found in a new locality. For detailed descriptions of the method of analysis, &c., see Journal of the Che- mical Society, and Chemical News, for 1867-8. Citrine. See Quartz. Clay. See Kaolin. Clay Ironstone. See Chalybite. Cleavage. A property possessed by many minerals of splitting more readily in certain definite directions than in others, and affording shining surfaces, usually plane, but sometimes curved, called "cleavage planes;" these cleavage planes have often a pearly lustre, even when the general lustre of the mineral is not pearly. The cleavages are usually parallel to some of the primary forms. Cleavelandite. See Albite. Cleiophane. See Blende. CLINOCLASE. [Klinoclase. Clinoclasite. Oblique Prismatic Arseniate of Copper.] Oblique; in small crystals, like Figs. 163 to 166 ; with a perfect cleavage parallel to O, more commonly in wedge-shaped or hemispherical aggregates, with curved cleavage ; and radiated, fibrous, or columnar structure ; brittle ; translucent to opaque ; lustre vitreous, pearly, or resinous ; dark green or dark blue ; streak bluish-green; H. 2 '5-3; G. 4 '2- 4'4 B., etc. Altogether like Olivenite, which see. Gomp. Hydrated arseniate of copper, as appears from the following analyses : a. b. Arsenic anhydride 29 '71 ... 27 '09 Oxide of copper 60'00 ... 62*80 Phosphoric anhydride ... '64 ... 1'50 Peroxide of iron 0'39 ... 0'49 Lime 0'50 ... Silica 112 ... Water 7'64 ... 7'57 Totals lOO'OO ... 99-45 The sp. gr. of a. was 4 '258 (4 '359 when powdered); that of b. was 4 '312. a. was analysed by Rammelsberg; b. byDamour ; both were Cornish specimens. With arsenic anhydride 30 '2, oxide of copper 62 "7, and water 7 "57 the formula may be written 6CuAs 2 + 3H 2 (oxygen ratio = 6:5:3) or (CuO) 3 As 2 O 5 -t-3CuH 2 O 2 or As 2 O 2 Cuo" 3 (CuHo 2 ) 3 . Loc. Ting Tang ; Huel Unity ; Huel Muttrell ; Huel Gorland, and other mines near St. Day, formerly ; Provi- dence Mine, Lelant ; and more recently at Bedford United Mines, near Tavis- tock, in hemispherical masses of a pure dark bluish-green colour ; also found in Germany. COAL. COMMON SPAE. 35 Obs. It may be distinguished from chalcophyllite by its higher specific gra- vity and darker colour, as also by its de- flagration on charcoal (chalcophyllite fuses quietly) ; from torbernite it may be distinguished by its different blowpipe reactions and darker colour. The crystals may always be recognised by their form. Allan observes, " The crystals usually present a very dark blue colour and bril- liant lustre," and " are easily recognisa- ble, being aggregated in divergent groups, or disposed in extremely minute indivi- duals in cavities in quartz." Angles. M M' = 56 00' O r = 123 48' M'O 95 00 ra 155 42 Os 80 30 sa 161 00 Oa 99 30 Ma 118 00 Clinodiagonal. The inclined lateral axis of oblique crystals is so called ; a cleavage plane parallel to this axis and the principal is called a clinodiagonal cleavage. Thus a cleavage parallel to b. in Fig. 160 will be clinodiagonal ; parallel to a. would be orthodiagonal. Coal. This is rather a rock than a mineral, but a few words here will not be out of place. The most evident group- ing of the different varieties of coal is as follows : 1. Anthracite. 2. CannelCoal. 3. Caking Coal. 4. Brown Coal or Lignite. Of these only the first and the last have occurred in the two western counties, and these mostly in Devonshire. The Lignites of Bovey Tiacey have been worked in connexion with its clays for many years. The following is an analysis of the Bovey Lignite, by Vaux (Journ. Chem. Soc. 1, 318, 1869): Carbon 66'31 Hydrogen 5'63 Oxygen 22 '86 Nitrogen 0'57 Sulphur 236 Ash ., 2-27 Total 100-00 "Thin intermittent beds of Anthra- cite stretch eastwards from Abbotshnm, on the shores of Barnstaple Bay, through Bideford in a straight line to Hawkridge "Wood, near Umberleigh, a distance of about twelve miles." (Keport Devon Assoc., 11, 11, p. 345.) Anthracite has been worked also at Tavistock. The author found a shining black carbona- ceous coating in the joints of the killas at Huel Jane (near Truro), and near Hayle. That from Huel Jane when scraped off and dropped into melted nitre, deflagrated, Ihus shewing its car- bonaceous nature. Cobalt Bloom. Cobalt Coating. Cobalt Crust. See Erythrite. COB A LTITE. [Cobaltine. Cobalt Glance. Bright White Cobalt.] Cubic; in crystals like Figs. 1, 2, 8, 32, 43, 45, 46, 48 ; cleavage perfect, parallel to a, the faces a usually striated as in pyrites ; more commonly massive, compact, granular, or dissemi- minate ; or stalactitic, botryoidal, reni- form, arborescent ; brittle ; fracture un- even ; opaque ; lustre metallic ; silvery or reddish-white, grey or greyish -black ; streak greyish-black ; H. 5-5 '5 ; G. 6-6 '3. B., etc. In matrass is unaltered, or gives a light yellow or white sublimate ; on C yields copious arsenical and sul- phureous fumes, deposits a white incrus- tation, and fuses to a grey brittle mag- netic globule ; with borax and micro, yields Co reactions ; decomposed by warm HNOs, depositing arsenic us anhydride and sulphur. Comp. Sulpharsenide of cobalt, often with nickel and iron. No analysis of a British specimen is known, but foreign specimens contain from 19 to 21 per cent, of sulphur, 43 to 45 arsenic, and 9 to 33 cobalt. With 19 "3 of sulphur; 45 '2 arsenic, and 35 "5 cobalt the formula may be written CoSAs or CoS 2 + CoAs 2 or Co(SAs) 2 . LOG. Botallack, in small particles, embedded in reddish quartz and chlorite ; it is said to have been found also at the Wherry Mine, Penzance ; Dolcoath ; Huel Sparnon ; and St. Austell; also Sweden, Norway, Germany. O6s. The crystals are most readily distinguished from smaltite by their cleavage. Angles. Same as pyrites. 00 = 109 28' a a = 90 00' &c. Cockle. See Tourmaline. Cockscomb Pyrites. See Marcasite. Cogwheel Ore. See Bournonite. Colour. A physical character, which is of considerable importance and very distinctive in minerals which have a metallic or submetallic lustre, as Pyrites, Galena, Wolfram, &c. , but of very little importance in those whose lustre is vitreous or resinous, as Cassiterite, Blende, Quartz, Calcite, &c. Varieties of these species are, however, often founded upon colour alone. Columnar. Made up of small columns. See Physical Characters of Minerals (Structure). Common Felspar. See Orthoclase. Common Spar. See Quartz. 36 COMPACT. COPPER. Compact. A term applied to speci- mens which exhibit ho peculiarity of structure. See Physical Characters of Minerals (Structure). Concentric lamellar. A structure re- sembling that of an onion. See Physical [ Characters (Structure). Concretion. Grown together. Nodules ; like those of chert and ironstone, the grains and spherules of oolite, and the grape-like clusters of the magnesian limestone are termed "concretions," as formed by a molecular aggregation, dis- tinct from crystallization. (Page, Hand- book of Geological Terms.) Conchoidal. Shell-like. When a mineral breaks with a curved fracture, ; somewhat like the inside of a shell, it is said to be conchoidal. Ex. Flint. Condurrite. See Domeykite. CONNELLITE. Hexagonal ; in small acicular crystals, like Figs. 228, 229 ; translucent ; lustre vitreous; colour fine blue ; streak light blue (?) ., etc. In matrass yields a little water with acid reaction, and decrepitates ; on C tinges the flame greenish-blue and fuses to a reddish globule ; with soda yields a bead of copper ; the slag gives the reaction for sulphur when moistened and placed on silver ; soluble in HC1 or HNO> Comp. Hydrated sulphatochloride of copper. No quantitative analysis is known. Loc. Huel Providence ; Huel Unity ; and Huel Damsel, formerly, in slender prisms, like Figs. 228, 229 ; also fibrous or massive, in thin veins with other copper ores. Obs. The colour of the massive mineral is much darker than that of the fibres or crystals. Only a few specimens are known, and these were all obtained many years ago. The crystals are about l-10th of an inch in length, and l-200th in thickness. Specimens may, perhaps, be found in old collections ranged with the arseniates and phosphates of copper. Anciles. P P over summit = 73 40' PP adjacent 132 50 Pa 143 10 PC 133 53 wV 163 50 ww" 137 10 we 156 02 wa 166 54 Pw 152 37 ac 150 00 cc 120 00 a a 120 00 Observed forma P w a c, PC. COPPER. [Native Copper.] Cubic ; in modified octahedrons, cubes, &c. ; crystals like Figs. 8 to 16, 59, 60, but usually indis- tinct ; often macled, or aggregated to form dendritic, capillary, or interlacing masses, also in thin laminse or massive ; malleable ; fracture hackly ; opaque ; lustre metallic ; copper-red, often with a brown tarnish, or thin green coating of malachite ; streak light red and shining ; H. 2'5 ; G. 8-5-9-0. B., etc. In matrass unaltered, or darkens on the surface somewhat ; on C fusible at 3 to a bead which is bright while hot, but covered with a dull black crust of oxide when cold, and generally tinges the flame slightly green ; when moistened with HC1 and heated colours the flame intensely blue ; soluble readily in HNO 3 , forming a green solution and giving off orange coloured fumes. Comp. Copper, almost pure ; contain- ing sometimes a little iron, silver, or bismuth. Loc. Botallack, Huel Cock, and other mines at St. Just, in ramose and mossy aggregations ; many parts of the Lizard district, in the joints of the serpentine ; Bellurian Cove and the Ghostcroft, near Mullion ; Pradannack, in conglomerate with pyrites ; Binner Downs and Tre- nance, near Helston; Leseave, Trewa- vas, New Hendra, and Huel Prosper, in Breage, (in thin veins); Owen Yean, St. Hilary ; Providence and other mines near St. Ives; East Relistian, and other mines in Gwinear ; Huel Crenver, in Crowan ; Huel Gorland, Huel Unity, and other Gwennap mines (Figs. 1, 2, and other forms, and in thin leaves filling joints in quartz); Huel Buller, Huel Basset, and other mines near Cam Brea ; Tresavean, lately, in arborescent forms with chlorite and oxide of iron; Condurrow, Dolcoath, Cook's Kitchen, and the mines near Camborne ; Cam Brea and Huel Druid, like Fig. 1, with a dull brown tarnish, and also in thin plates, dendritic, and mossy ; Huel Music, Polberrow, and other mines in St. Agnes ; Great St. George Mine, Perranzabuloe ; Crinnis and Great Dowgas, near St. Austell ; East Crinnis, Par Consols, and Lanescot, near St. Blazey (reticulate); Gunnislake ; "West Caradon ; Fowey Consols ; Phoenix ; Devon and Courtenay, Devon Great Con- sols, Huel Crebor, and other mines near Tavistock ; also many other parts of Eng- land ; Wales, Scotland, Ireland, and most of the countries in Europe, and many parts of Asia, Africa, America, and Australia. Obs. Copper may be readily recognised COPPEB BLACK. CEOMFOEDITE. 37 by its colour when freshly cut, and its malleability. Figs. 3 and 4 are com- pressed macles observed in Cornish spe- cimens. Angles, 00= 109 28' a d = 135 00' a a 90 00 ae 153 26 dd 120 00 ee' 143 08 ao 125 16 de 161 34 d o 144 44 Copper Black. See Melaconite. Copper Glance. See Chalcocite. Copper Green. See Chrysocolla. Copper Mica, See Chalcophyllite and Torbernite. Copper Nickel. See Mccolite. Copper Pyrites. See Chalcopyrite. Copper Vitriol. See Cyanosite. Copper Uranite. See Torbernite. Copperas. See Melanterite. Coralloid. Branched like a coral. Ex. flos-ferri. Cornish Diamond. See Quartz. Cornish Tin Ore. See Cassiterite ("Wood Tin). CORNWALLITE. Amorphous ; reniform, or minutely botryoidal ; compact or disseminate in or on Olivenite ; brittle ; fracture conchoi- dal ; lustre non-metallic ; rich verdigris or dark green ; streak the same ; H. 4'5; G. 41-4'3. /?., etc. In matrass and on C like Olivenite. Comp. Hydrated arseniate of copper, as appears from the following analyses : a. b. c. d. Arsenic anhy- dride 2978 30*65 30 '00 29 '00 Phospho ric anhydride.. 2 '54 177 Oxide of cop- per . 55-00 54-22 54 '00 51 '00 Water 12 '68 13 '36 16 '00 18 '00 Total ... 100-00 100-00 100 '00 98 '00 All were Cornish specimens, a. and b. were analysed by Lerch; c. and d. by Chenevix ; the sp. gr. of d. was 4 '28. Another analysis by Lerch (e.) is given below, compared with twc recent analy- ses by Church, (f. and g.) e. f. g. Oxide of copper 54'61 59'95 58'33 Arsenic anhydride... 30 '21 30 '47 3375 Phosphoric an- hydride 216 271 Water ... .. 13'02 8 '25 7 '92 Totals 100-00 101-38 100 '00 In the analyses f. and g. the water la much less than in the other. If in the earlier analyses the water were merely determined by difference, the anomaly might easily be explained. With arsenic anhydride 32 '0 per cent., oxide of cop- per 55-4, and water 12 '6 the formula may be written As 2 5Cu5H 3 or Cu 3 2AsO 4 + 2CuH 2 O 2 + 3H 2 O or As 2 O 2 Cuo" 3 + 2CuHo 2 + 3OH 2 . This shews it to be closely related to ehlite. Church adopts the/or- mula As 2 5Cu3H 2 . Loc. Probably some of the Gwennap Mines. Obs. It may be readily distinguished from chrysocolla, which it much resem- bles, by its hardness and blowpipe reac- tions ; from malachite, by its solubility without effervescence in COVELLITE. [Covelline. Indigo Copper.] Hexa- gonal ; with perfect basal cleavage ; crys- tals very rare ; usually massive, folia- ceous ; reniform, investing, pulverulent, or granular ; sectile ; thin leaves flexible ; opaque ; lustre submetallic, pearly, or greasy ; deep blue ; streak black, or dark lead-grey; shining; H. 1*5-2; G. 3 '8 to 3'9 ; crystals 4 '6. ., etc. In matrass givei a sublimate of sulphur ; in open tube sulphureous fumes ; on C burns with a blue flame and sulphureous odour, and fuses to a glo- bule of copper, which is more perfectly reduced by the addition of a little soda ; decomposed by HNO 3 , forming a green solution, and leaving a white deposit of sulphur. Comp. Anhydrous sulphide of copper. No analysis of a British specimen is known, but foreign pecimens yield from 32'0 to 34-3 per cent, of sulphur and 64 '5 to 66 "0 of copper, with usually a little lead or iron. With copper 66 "5 and sul- phur 33-5 write Cu 2 S 2 or CuS. Loc. Huel Kind, St. Agnes; Huel Maudlin, investing chalcopyrite ; Cam Brea, pulverulent ; also Vesuvius, Saxony, Poland, Thuringia, &c. CROMFORDITE. [Phosgenite. Horn Lead.] Pyramidal ; usually in four-sided prisms more or less modified; with three easy cleavages forming angles of 90 0' and 135 0'; brit- tle or almost sectile ; fracture conchoi- dal; transparent to translucent; lustre adamantine to waxy ; white, or greyish, yellowish, greenish, brownish; streak whibe; H. 2-5-3; G. 6-6 '3. ., etc. In matrass melts and some- times turns darker while hot ; on C melts at 1 to a yellow globule, which becomes white and crystalline on 38 CEONSTEDTITE. CRYSTALLOGRAPHY. cooling ; in RF gives a bead of lead with white coating of chloride of lead ; with a micro, and oxide of copper gives the re- action for chlorine ; soluble with effer- vescence in HNO 3 . Gomp. Anhydrous chlorocarbonate of lead. The Cornish specimen has not been analysed, but three specimens from Derby- shire yielded the following results : a. b. c. Carbonate of lead ... 48 '4 48 "45 48*22 Chloride of lead 53 '5 50 '93 51 '78 a. by Klaproth, b. by Eammelsberg, c. by Smith. "With carbonate of lead 49' and chloride of lead 51 '0, or oxide of lead 81 '9, carbonic anhydride 8'1, and chlorine 13 '0 the formula may be written PbC + PbCl 2 orPbCO 3 + PbCl 2 or COPbo"PbCl 2 . Loc. One specimen only has been found in Cornwall, which is like Fig. 78, its exact locality is believed to be Huel Confidence, Newquay, St. Columb Minor. It occurred in a gozzan. Also Derby- shire and Scotland, Sardinia and Silesia, but very rare. Some crystals from Der- byshire were sold at prices from 15 to 20 each. Obs. It may be readily distinguished from Cerussite by the reaction for chlo- rine with oxide of copper, and by the form of the crystals. The cleavages are parallel to O, M, a. Angles. M O = 90 (MX O x = 123 08' MM 90 00 Os 112 24 Oa 90 00 xx' 113 48 Ma 135 00 xx 107 21 M u 161 34 s a 145 47 MX 146 54 ss 131 10 Ms 151 26 CRONSTEDTITE. [Chloromelane.] Hexagonal; in three or six-sided prisms, vertically striated, and often in radiating aggregations of such prisms, tapering somewhat toward the summit, sometimes in hemihedral or macled forms, like Figs. 219, 236, 237, 238 ; or reniform ; or massive, fibrous, or amorphous ; cleavage parallel to O, very perfect, sometimes curved ; brittle ; thin fibres, somewhat flexible and elastic ; translucent to opaque ; lustre vitreous, brilliant ; black ; streak very dark green ; H. 2-5-3-5; G. 3 '3 to 3 '5. B., etc. In matrass gives off water; on C froths and fumes somewhat on the edges, yielding in the RF a grey or black magnetic globule ; with borax gives the reactions for iron and manga- nese ; with soda on Pt. foil the reaction for manganese ; decomposed by strong HC1, leaving a deposit of gelatinous silica. Comp. Hydrous silicate of iron. Two analyses of Cornish specimens, by Pro- fessor N. S. Maskelyne and Dr. Flight, yielded the following results : a. b. Iron peroxide 36 '762 32752 Iron protoxide 36 '307 38 '570 Silica , 17-468 18'546 Lime 0'087 Water..., , 10 '087 10132 Totals 100711 lOO'OOO With protoxide of iron 41'54, peroxide of iron 30 '77, silica 17 '31, and water 10*38 the formula may be written 3FeSi O 4 + 4(Fe 2 ) vi H 6 O 6 . A small sample very carefully picked actually yielded 41*272 of iron protoxide. Loc. Huel Maudlin, Lanlivery, in divergent groups, like Figs. 219, 236, 237, 238, on chalybite and decomposing pyrites, with Hisingerite and Vivianite ; also found in Bohemia and Brazil. Obs. It is one of the rarest British minerals, only a few specimens having been obtained. Some recent observations on the peculiarities of its form, &c. , will be found in the Journal of the Chem. Soc. for Jan., 1871, p. 11. Crosscourse Spar. See Quartz. Cryptocrystalline. Amorphous. Crystal. Minerals which occur in geo- metrical forms are said to be crystallized. Each specimen is a " crystal," twin crys- tal, or group of crystals. The surfaces are termed "planes," even when curved, rough, or striated. The meeting of two planes produces an " edge ;" of three or more planes an ' ' angle. " Crystalline. Made up of small and indistinct crystals. Crystallography. The science of crys- tals. The numerous forms of crystals met with in nature are usually referred to six simple types or "systems," depending upon the number, position, and relative lengths of certain imaginary lines called " axes," to which the various planes are referred. Some of the names which these systems have received from various writers are here set down, the first men- tioned being the names adopted in this work. 1. CUBICAL. Trimetric. Monometric. Orthotype. Tessular. Orthorhombic. Isometric. One & one axial. Kegular. 4. OBLIQUE. 2. PYRAMIDAL. Monoclinohedric. Tetragonal. Monoclinic. Dimetric. Hemiorthotype. Two & one axial. Two & one inem 3. RHOMBIC, bered. Prismatic. 5. ANOETHIC. CUBE. CUPEITE. Triclinohedric. 6. HEXAGONAL. Triclinic. Rhombohedral. Anorthotype. Three &one axial. One & one mem- bered. 1. Cubical. THREE AXES, AT EIGHT ANGLES, EQUAL IN LENGTH ; primary form, the octahedron (Fig. 1), or the cube (Fig. 2). 2. Pyramidal. Three axes, at right angles, two equal, one longer or shorter. The unequal axis is called "principal," the other two are ' ' lateral. " Primary form, a double pyramid with square base, or a prism with square base. 3. Rhombic. THREE AXES, AT RIGHT ANGLES, ALL UNEQUAL. One is chosen for the " principal," of the remaining axes the longer is termed ' ' macrodiago- nal," the shorter " brachy diagonal. " Primary form, a double pyramid on rhombic base, or a prism on a rhombic base. 4. Oblique. THREE AXES ; TWO IN- TERSECT EACH OTHER AT AN OBLIQUE ANGLE, AND ARE CROSSED BY THE THIRD AT RIGHT ANGLES ; ALL UNEQUAL IN LENGTH. One of the oblique axes is chosen for principal ; the one which forms a right angle with this is termed " orthodiagonal," the other lateral axis is " clinodiagonal. " Primary form, an oblique double pyramid, or oblique prism. 5. Anorthic. THREE AXES, ALL IN- CLINED, ALL UNEQUAL. One is chosen for principal, the others are macro and brachydiagonal. Primary form, a doubly oblique double pyramid, or doubly oblique prism. 6. Hexagonal. FOUR AXES ; THREE LATERAL, EQUAL IN LENGTH AND LYING IN ONE PLANE, AND MAKING WITH EACH OTHER ANGLES OF 60, THE FOURTH PRIN- CIPAL, AT RIGHT ANGLES, AND OF ANY LENGTH. Primary form, a double pyra- mid on a hexagonal base, or a prism on the same base. Cube. A solid six-sided figure, the sides equal squares. (Fig. 2.) Cube Ore. See Pharmacosiderite. Cupellatioi.. A method of separating the noble metals from lead and other impurities. It may be successfully per- formed on a small scale as follows : A hole is made in a piece of charcoal, about one -half of an inch wide and the same in depth. This is filled with slightly mois- tened bone ash (a bone burnt in an open fire and finely crushed will do very well), and pressed down with some smooth con- vex surface so as to produce a correspond- ing smooth concavity. In this hollow the assay, mixed with several times its weight of lead (unless the sample be a lead ore), is placed, and treated with a strong oxidising flame. The lead will become oxidised and sink into the bone ash, carrying any impurities with it, and leaving the noble metal, gold or silver, as the case may be, on the surface. If the operation be well done the bead will be very nearly a perfect sphere. In this way silver may be detected in a few grains of almost any specimen of galena, a mag- nifying glass being used to detect the bead of silver. CUPRITE.' [Red Copper Ore. Red Oxide of Cop- per.] Cubical; in cubes, octahedrons, rhombic dodecahedrons, and other forms (Figs. 1, 2, 3, 8, 9, 10, 11, 12, 13, 14, 15, 16, 24, 30, &c.); cleavage parallel to O, perfect ; also fibrous, granular, compact, earthy, or disseminated ; brittle ; frac- ture conchoidal or uneven ; subtranslu- cent to opaque ; submetallic, adaman- tine, silky ; splendant to dull ; various shades of red to dark reddish-grey, often with a dark brown tarnish, or sometimes a green coating of carbonate ; streak brownish-red, shining, or earthy ; H. 3*5-4; G. 5-6-6-2. Var. Chalcotrichite, capillary red oxide, or plush copper, is a fibrous variety, with silky lustre and very beau- tiful red colour, which seems made up of elongated cubes. Tile ore is a massive earthy variety, which often contains a considerable pro- portion of oxide of iron. Ruby Copper consists of small and brilliant crystals of a dark red colour. B. , etc. In matrass no change, or be- comes darker ; on C with a strong flame, RF, is reduced to a bead of Cu ; with borax and micro, gives Cu reactions ; if moistened with HC1 tinges the tip of the flame bright blue ; soluble in HC1, HNOs, and ammonia. Gomp. Anhydrous cuprous oxide. The following analysis of a Cornish specimen is by Chenevix : Copper 85'5 Oxygen 11*5 Total 97-0 With copper 88 78 and oxygen 11 '22 the formula may be written Cu 2 or Cu 2 O. Loc. Fine specimens of crystallized cupr'te have been obtained from Huel Basset, South Huel Basset, South Huel Frances, Huel Buller, Huel Druid, and other mines near Redruth ; Huel Music ; Dolcoath ; Cam Brea ; Tincroft ; Huel Unity ; Huel Gorland ; Huel Prosper ; 40 OYANOSITE. DEMIDOFFITE. Huel Muttrell; Huel Virgin; Ting Tang ; Treskerby ; Huel Crenver ; Huel Abraham ; St. Ives Consols ; Huel Ed- ward, Huel Speed, Botallack, and other St. Just mines ; Mullion, and other places in the Lizard district ; Pplgear, Wendron ; Fowey Consols ; Gunnislake ; Phoenix Mines ; Carvath United, Cals- tock ; Huel Crebor ; Devon Great Con- sols ; Bedford United ; and other mines in Devon and Cornwall. Chalcotrichite has been found at South Huel Frances ; West Huel Basset ; Huel Unity ; Huel Gorland j Owen Vean, St. Hilary ; Gunnislake ; Phoanix ; Fowey Consols ; Huel Charlotte, St. Agnes (1825); &c. Tile Ore occurs in very many of the above-named mines. Cuprite occurs also in France, Spain, Germany, Italy, Sibe- ria, Australia, Cuba, Chili, the United States, &c. , Obs. The figures referred to above are all Cornish or Devonshire forms. Angles. 00= 109 28' n a = 144 44' a a 90 00 no 160 32 d d 120 00 p o 164 12 oa 125 16 pd 160 32 da 144 44 CYANOSITE. [Chalcanthite. Blue Vitriol.] Anor- thic ; crystals somewhat like Fig. 183, with an imperfect cleavage parallel to M ; also amorphous, stalactitic, renif orm, fibrous, pulverulent ; brittle ; fracture conchoidal or uneven; semitransparent to translucent ; lustre vitreous ; various shades of blue, or greenish-blue ; streak white; H. 2 '5; G. 2 '2-2 '3; taste very nauseous and metallic. ., etc. In matrass melts very readily at first, gives off large quantities of water and acid vapours with a strong smell of sulphur ; finally becomes a nearly white dry mass ; on C is readily reduced to a bead of Cu, tinging the flame green ; soluble in water, forming a blue solution, which deposits a film of Cu upon clean iron. Comp. Hydrated cupric sulphate. When pure its composition is nearly Oxide of copper 32'00 Sulphuric anhydride 32 '00 Water ... .36'00 Total 100-00 This may be represented by the follow- ing formulae :CuS + 5H 2 or CuSO 4 + 5H 2 or SO a Cuo"50H 2 . Loc. Ting Tang, and other mines in Gwennap, in crystals nearly an inch long, formerly ; St. Ives Consols ; Tre- varthen, near Marazion ; Botallack, in the Crown's lode, at 165 fathoms from the surface, fibrous and crystallized ; South Frances, and other mines near Kedruth ; West Huel Jane ; Gunnislake, fibrous and massive ; also found in Wales, Ireland, Hungary, Germany, Sweden, Spain, Chili, &c. 06s. It is often found on burrows and in old workings, and is a product of the decomposition of other copper ores. The water from most copper mines has usu- ally some cyanosite in solution. Works for the extraction of the copper have been established from time to time at Carnon, Perranzabuloe, and other places. For this purpose it is only necessary to leave pieces of scrap iron in the cupreous water, when the copper is slowly preci- pitated upon the iron. Beautiful speci- mens of precipitated copper are occasion- ally found on nails and fragments of iron in the old workings of copper mines. A ngles. O M = 108 12' M n = 153 44' OT 127 31 Mv 126 10 MT 123 10 Ov 125 38 Mr 126 57 D. Dark Eed Silver Ore. See Pyrargyrite. Decomposed. Separated into its ele- ments, or into less complex parts. Decrepitation. The crackling noise heard when many minerals are suddenly heated. The mineral usually flies to pieces. Ex. Blende, Wolfram, Deltohedron. A regular solid geome- trical figure, bounded by 24 equal "del- toids " (Fig. 5). It is a common form for crystals of garnet, and hence is sometimes called the granatohedron. Deltoid. A plane four-sided figure, such, that one of its diagonals divides it into two equal scalene, and the other into two unequal isosceles triangles. DEMIDOFFITE. Amorphous ; earthy ; translucent to opaque; surface splendant; sky blue or greenish; streak blue; H. 2; G. 2 '25. B. , etc. In matrass turns darker and gives off water ; on C alone turns dark ; with borax yields a grain of copper ; de composed by acids, depositing silica. Comp. Hydrated silicate and phos- phate of copper. Loc. It is said to be found in Corn- wall (Bristow's Manual of Mineralogy, p. 107) ; and in Cumberland, in company with quartzose ro^k and malachite ; also Valparaiso. DIALLOGITE. DOLOMITE. 41 Obs. It covers some of the malachite of Nischne Tagilsk in delicate layers. Dendritic. Tree-like, branched. A term applied to the branching forms com- mon in native silver and other minerals. Desmine. See Stilbite. Devonite. See Wavellite. Diallage. See Pyroxene. DIALLOGITE. [Carbonate of manganese.] Hexago- nal ; in small rhombohedrons, drusy ag" gregates, reniform masses, earthy crusts? or pulverulent ; brittle ; fracture uneven ; opaque or translucent on thin edges ; vitreous to pearly ; rose-red or brownish, often with a dark tarnish ; H. 4-5 ; G. 3'4-3-G. B. , etc. In matrass turns darker ; on C alone infusible ; with soda forms a green bead ; with micro, or borax gives Mn reactions ; soluble with effervescence in warm HC1 or HNO 3 . Oomp. Anhydrous carbonate of man- ganese. Church obtained from a Corn- ish specimen, of a pale rose red colour, and very pure : Oxide of manganese 60*29 Oxide of iron 1*65 Carbonic anhydride 38 '36 Total 100-30 Pure specimens have the following composition : Oxide of manganese 61 "76 Carbonic anhydride 38 '24 "With this composition the formula may be written MnC or MnCO 3 or COMno". The manganese is often partially replaced by magnesia or lime. Loc. Said to have been found at Bovey Tracey, Botallack, and Huel Owles ; also found in Shropshire, War- wickshire, Ireland, Germany, Hungary, Transylvania, Spain, United States, &c. Diaphaneity. A general term expres- sing the degree of transparency or opacity of minerals. The several degrees are : a. Transparent. Outlines can be dis- tinctly seen through such sub- stances. b. Semitransparent. Outlines may be seen, but are indistinct. c. Translucent. Light passes through, but no outline can be seen. d. Subtranslucent. Light is only trans- mitted through thin edges or splin- ters. e. Opaque. No light is transmitted. Dichroic. Minerals which appear to be of two different colours by transmitted light, according to the direction in which they are viewed, are said to be dichroic. Those which appear of three colours are said to be trichroic. Tourmaline is often dichroic, and axinite is trichroic. Dihedral. Having two planes. A crystal like Fig. 160 is said to be a prism with a dihedral summit. Dimorphism. This term is used to express the property possessed by some substances (both simple and compound), of crystallizing in forms derived from two distinct sets of crystallographic axes. Thus carbon as diamond is CUBICAL, but as graphite it is HEXAGONAL. A sub- stance which crystallizes in three forms is trimorphous. Sometimes the term polymorphous is used when the substance appears in more than two forms. The following cases of dimorphism occur in Cornwall or Devon : Sulphide of Iron, f Pyrites : CUBIC. FeS 2 . ( Marcasite : EHOMBIC. Carbonate of ( Calcite : HEXAGONAL. Lime, CaCO 3 . ( Aragonite : EHOMBIC. The following is a case of trimor- phism : Titanic [Entile: PYRAMIDAL. anhydride, < AnataserPYKAMiDAL. TiO 2 . (Brookite: EHOMBIC. Disseminated. Sown or scattered. A term applied to minerals, whether crys- tallized or not, which seem to be scat- tered in small particles through a mass of another kind of matter. Divergent. Crystals which diverge from a common point of support are said to be divergent. Dogtooth Spar. See Calcite. Dodecahedron. A solid figure, bounded by 12 planes. The chief dodecahedrons are the following : a. Rhombic Dodecahedron (Fig 3). This is bounded by 12 equal rhombs. b. Deltoid Dodecahedron (Fig. 34). Bounded by twelve equal deltoids. c. Trigonal Dodecahedron (Fig. 35). Bounded by twelve equal triangles. d. Pentagonal Dodecahedron (Fig. 43). Bounded by twelve pentagons. DOLOMITE. [Bitter Spar. Brown Spar. Pearl Spar.] Hexagonal; in rhombohedrons, which are often curved ; or in other forms resembling those of calcite and chalybite (Figs. 197 and 231); cleavage perfect, parallel to E, but often curved ; also massive, granular, or compact; translucent to opaque; lustre vitreous, resinous, or pearly, especially on cleav- ages ; white, yellow, brown, greenish, reddish, black ; streak white, or slightly tinged as the colour in coloured varie* ties; H. 3-5-4; G. 2 -8-31. 42 D01LEYKITE. ELECTRICITY. Far. a. Bitter Spar is a variety with a bitter taste. b. Brown Spar is the name given to dark brown varieties. c. Pearl Spar includes those varieties which have a pearly lustre. d. Ankerite is a variety containing a considerable proportion of carbonate of iron. #., etc. In matrass unchanged ; on C alone infusible, but becomes alkaline ; wben treated with Co the light-coloured varieties turn pink or reddish ; the darker varieties often turn brown or black from the presence of iron ; slowly soluble in HC1 or HXO 3 , with but a slight effervescence. Comp. Anhydrous carbonate of lime and magnesia, with very often some iron or manganese. The mean composition of pure specimens is somewhat as follows : Lime 30-34 Magnesia 21 '80 Carbonic anhydride 47 '86 Total 100-00 "With this composition the formula may be written CaMg2C or CaC0 3 + MgCO 3 or C 2 O;jCao"Mgo". LOG. Botallack, Huel Castle, Huel Owles, Levant, St. Just Amalgamated, and other St. Just mines, on quartz and brown iron ore; St. Ives ; New Rose- warne; Trevascus; North Roskear; West Chiverton ; Great South Chiverton ; Pen- hale ; Polgooth ; Garras ; South Hooe ; Beerferris ; Beeralstone, on flujr; near Kitley Park, rose-coloured ; also Cum- berland, Yorkshire, Scotland, Germany, Italy, Switzerland, Hungary, Tyrol, Norway, Sweden, the United States, &c. Obs. It is perhaps only a variety of calcite, rich in magnesia. It seems to pass into chalybite by an increasing pro- portion of iron. It may be distinguished from calcite by its superior hardness and density. Angles. Nearly the same as those of calcite. RR' = 73 55' R'R' = 106 15' DOMEYKITE. (Condurrite. Arsenical Copper Py- rites.] Amorphous ; massive or disse- minate ; fracture uneven or flat conchoi- dal ; lustre metallic or dull ; tin-white, yellowish, brown, or black ; H. 1-3 "5 ; G. 4-5. Far. Condurrite is a variety which is brownish-black externally, but tin-white or yellowish on a freshly exposed surface. It is so soft as to soil the fingers. B., etc. In matrass yields usually some water, and a white or yellowish sublimate ; on C fuses at 1, giving off arsenical fumes; with soda and borax yields a bead of copper ; insoluble in HC1 ; ^partially soluble in HNO> Comp. Anhydrous arsenide of copper, the water being only mechanical and in partially decomposed specimens. The analyses of Blyth (a) and Faraday (b) gave as the mean composition of con- durrite a. b. Arsenic 28'85 ... 29'89 Copper 7115 ... 7011 Totals 100-00 '.'.'. 100-00 With arsenic 28 7 and copper 71 "3, the formula may be written Cu 3 As or AsCu 3 . Loc. Condurrite has been found from time to time at Condurrow Mine, Cam- borne ; and at Huel Druid, Redruth, in dark coloured, nodular, earthy masses. Dropstone. A local name for Stalag- mites. Drusy. "Dewy." A surface which appears sprinkled with very small crys- tals ; or the crystals themselves. E. Earthy. A mineral; the surface of which when broken is somewhat soft, and presents a multitude of minute prominences without lustre, is said to be earthy. An earthy smell is that which is yielded by clayey substances when breathed upon. Earthy Manganese. See Wad. Effervescence. The peculiar frothy appearance observed when acids are poured upon limestone, and all similar phenomena, are called effervescence. It arises from the rapid disengagement of a multitude of minute bubbles of gas. Efflorescence. The peculiar powdery appearance produced on crystals of car- bonate of soda and other substances when exposed in dry air is so called. Eisenkiesel. A ferruginous variety of quartz. Eisennickelkies. See Pentlandite. Elastic. A mineral which, after being bent, flies back to its original position, is said to be elastic ; mica is elastic ; talc, which often much resembles it, is only flexible. Electricity. One of the physical char- acters of minerals. Some minerals be- come electric by friction, some by heat, and some by percussion. A very simple electroscope may be made from a bent glass rod, from which a small fragment of gilt paper is suspended by a thread ELEMENTS. EEINITE. 43 of silk. On approaching a substance, the electricity of which is excited by the above or any other methods, the sus- pended fragment will move towards it. Many interesting experiments in electri- city may be made by means of this simple instrument. The electricity excited by these simple means is not always of the same kind. Thus, fluor and apatite become negatively, wolfram, mispickel, and cassiterite positively electrified by friction. The kind of electricity varies, however, in the same mineral, according to the smoothness or roughness of the rubbed surface. Elements. Substances which have not as yet been decomposed. About sixty-three elements are known to che- mists, but the great majority of mineral substances are made up of a few only. The elements most commonly met with in the mineral kingdom are Oxygen, Aluminium, Hydrogen, Magnesium, Nitrogen, Iron, Carbon, Potassium, Silicon, Sodium, Calcium, Sulphur. See Part I. of this work for a complete "TABLE OF THE ELEMENTS," with their specific gravities, &c. Elvan. A Cornish name applied to the porphyritic dykes which intersect most of the mining districts. Many of them are highly felspathic, and some contain disseminated crystals of felspar, quartz, schorl, pinite, and other minerals. Emerald. See Beryl. Endellionite. See Bournonite. EPIDOTE. Oblique ; in modified, often macled prisms ; one perfect cleavage, parallel to M (Fig. 159), and oue imperfect, making angles of 115 24' ; also columnar, granu- lar, radiating, or massive ; brittle ; frac- ture uneven, conchoidal, or splintery ; semitransparent to translucent on thin edges ; vitreous ; pearly on cleavage ; green, yellow, red, brown, black, often pleochroic; streak white; H. 6'5; G. 3-3-5. VOLT. The epidotes are divided into four groups, as follows : a. Lime and iron epidote. b. Lime epidote. c. Manganesian epidote. d. Cerium epidote. The Cornish specimens are probably of the class a., but no analysis has been made, the mineral being so scarce. B. , etc. In matrass no change ; on C fusible to a glass, especially the dark varieties ; with borax gives reactions for Fe or Mn ; with micro, the same, leav- ing a skeleton of silica in the bead ; in- soluble in HC1 or HNO 3 ; after ignition partly soluble, depositing powdery or gelatinous silica. Comp. Anhydrous silicate of alumina, iron, and lime. No analysis of a Cornish specimen is published, but foreign speci- mens yield about 38 '0 per cent, of silica, 21 '0 of alumina, 16 'Oof peroxide of iron, and 24 '0 per cent, of lime, with traces of magnesia. Sometimes the iron is partly replaced by manganese. With silica 381, alumina 21 '6, lime 23 '5, per- oxide of iron 16 '8, the formula may be written Fe 2 2Al 2 4Ca6Si or 4CaOSiO 2 + 2Si0 2 -t-2Al 2 3 + Fe 2 3 . Loc. Crowns' Rock, Botallack, in thin light green radiating groups of crystals, on dark hornblende rock ; Mr. J. Carne observes, "Epidote is visible in many other parts of the same cliff, in veins, and has also been found in the tin and copper lodes." (Trans. Roy. Geol. Soc. of Cornwall, vol. ii.); Carn Silver, with Pyrites ; Lamorna Cove, at the junction of the granite and slate ; Mara- zion, in quartz ; St. Keverne ; South Tresavean, in green acicular crystals, &c. ; also Cumberland, Wales, Scotland, Ire- land, Norway, France, Tyrol, &c. Obs. The crystals hitherto discovered in Cornwall have not been at all well defined in form ; some are not unlike blades of grass, radiating from a centre, and pressed flat to the surface of the rock. Angles. M r = 11G Q 17' M z = 104 16' Ml 90 33 rn 125 16 Mn 104 49 zz 109 51 The face 1 is often striated. Equivalent That weight of an ele- ment which is required to displace one part of hydrogen from a compound, or which one part of hydrogen will displace. ERTNITE. Crystallization unknown ; mammi- lated, fibrous, concentric ; brittle ; opaque or subtranslucent ; lustre resi- nous or dull; emerald-green to grass- green ; streak apple-green, or paler than colour; H. 4 '5-5; G. 4 '4. B., etc. In matrass decrepitates and gives off water ; on C fuses, giving off ar- senical fumes ; with borax yields a bead of copper ; soluble in HXO 3 . Comp- Hydrated arsenia^e of copper. The following analysis is by Turner :- - ERUBESCITE. ERYTHBITE. Arsenic anhydride 3378 Oxide of copper 59*44 Alumina 1 77 Water 5'01 Total lOO'OO With arsenic anhydride 34 '7, oxide of copper 59 9, and water 5*4 the formula might be written As 2 5Cu2H 2 or CuO 3 As 2 O 5 -t-2CuH 2 O2 or As 2 O 2 Cuo" 3 2CuHo 2 . LOG. It has been found in old Cornish collections by Professor Church. Obs. It is said by Haidinger to come from the county of Limerick, in Ireland, hence the name. It occurs in mammi- lated and concentric crusts, with a crystalline fibrous structure, and rough surfaces, which are probably the termi- nations of minute crystals. EEUBESCITF. [Purple Copper. Bornite. Horseflesh Ore. Buntkupferz.] Cubical; usually in cubes modified at the angles (Fig. 9), or macled (Fig. 58); the faces are some- times curved ; also massive ; sectile or brittle ; fracture imperfect conchoidal or uneven ; opaque ; lustre metallic ; copper-red to bluish or brownish ; often an iridescent tarnish ; streak greyish- black, shining ; scratch brownish or pur- plish ; H. 3-3; G. 4-4-4-5. .5., etc. In matrass gives a yellow sublimate ; on C melts to a black or dark reddish-brown, magnetic, brittle glo- bule ; when roasted and treated with a little borax yields a bead of copper ; if moistened with HC1 colours the flame blue ; soluble in HC1 or HNO 3 , forming a green solution. Comp. Anhydrous sulphide of copper and iron. The following are analyses of Cornish specimens, a., a specimen from Condurrow Mine, by Plattner ; b., from a mine near Redruth, by Chodnew ; both crystallized : a. b. Copper 56-76 ... 57'89 Iron 14-84 ... 14'94 Sulphur 28-24 ... 26'84 Totals 99-84 ... 99'67 With copper 62 "5, iron 13 '8, and sulphur 23 '7 the composition would be expressed by the formula FeCu. 2 S 3 or 2CuS, FeS. The iron, however, seems to replace the copper in different proportions. Loc. Pennance Consols, in crystals like Fig. 58; South Tolgus, Huel Buller, and other mines near Redruth ; Carn Brea, Dolcoath, Tincroft, Cook's Kit- chen, Condurrow, Camborne Vean, and other mines near Camborne ; Tresavean ; Huel Jewell; Huel Falmouth; Botal- lack, Levant, and other St. Just mines ; Huel Alfred; Huel Boys; Great St. George ; Britannia and Prince Regent, &c. ; also Somerset, Ireland, Norway, Siberia, Silesia, Bannat, Hesse, Hun- gary, &c. Obs. It may be readily distinguished from grey copper (chalcocite) by its supe- rior hardness and by the form of the crystals; from chalcopvrite by the colour of the scratch, which is always yellow in chalcopyrite, but always brownish-pur- ple in erubescite. Angles. a a = 90 00' 00 = 109 28' ao 125 16 ERYTHRITE. [Erythrine. Cobalt Bloom. Arseniate of Cobalt.] Oblique ; in acicular prisms, like Figs. 170, 171 ; with a perfect cleav- age parallel to M ; more usually in aci- cular crystals or radiating groups ; or earthy crusts ; sectile ; thin plates flex- ible ; translucent to opaque ; pearly, vitreous, or dull ; colour crimson, or other shades of red, usually tinged with blue, often peach-blossom red, occasion- ally greenish or greyish ; streak like the colour, but paler ; sometimes the same crystal will be both green and red ; H. 1-5-2-5; G. 2-9-3. B., etc. In matrass gives off water and deposits a white crystalline subli- mate ; on C melts to a grey brittle glo- bule, depositing a white incrustation at some distance from the assay, and giving off a powerful odour resembling garlic ; with borax and micro, a dark blue bead is formed ; soluble in HC1 and HNO 3 , forming a pink solution ; turns black if treated with KHO. Comp. Hydrous arseniate of cobalt ; the cobalt often partially replaced by nickel. No analysis of a Cornish speci- men is known, but foreign specimens yield from 38 "0 to 54*0 per cent, of arse- nic anhydride, 18'0 to 36 '0 per cent, of oxide of cobalt, and 12'Oto 24 '0 per cent, of water. With arsenic anhydride 38 '43, oxide of cobalt 37 '55, water 24 '02, the formula may be written As 2 3Co8H 2 or (Co) 3 As 2 O 5 + SH 2 O or As 2 O 2 Co 3 " + 8OH 2 . Loc. Botallack, near Crown's Engine, with cobaltite and smaltite ; Roscom- mon cliff, with axinite ; Huel Tre- noweth ; Huel Unity ; Dolcoath ; Huel Sparnon and East Pool, on smaltite ; Pednandrea ; Polgooth ; Trugoe ; Wills- worthy Mine, Tavistock; also Cumber- land, Germany, Hungary, &c. Obs. The earthy peach-blossom varie- ties are often found on ores of cobalt which have been left in damp situations. ERYTHEITE. FELSPAR. 45 Angles. OT = 124 51' Ts = 137 06' MT 90 00 On 149 12 Tk 155 05 OM 90 00 Erythrite. An old name for a peculiar red variety of felspar. F. FA HLERZ. [Tetrahedrite. Grey Copper. Falilore.] Cubical ; usually in tetrahedrons, more or less modified, like Figs. 33, 35, 38, 39, 40, 41, 42 ; also massive or disseminated ; brittle ; fracture conchoidal, uneven, or even ; opaque, or very slightly translu- cent on thin edges; metallic or sub- metallic ; steel grey to iron black ; crys- tals often rough and beautifully irides- cent ; streak brownish, reddish, or black; H. 3-4; G. 4 '5-5 '2. Var. Polytelite, or Freibergite, is a variety containing a notable proportion of silver. Tennantite is, perhaps, an arsenical Fahlerz. #., etc. In matrass gives a red or red- dish-yellow sublimate ; on C fuses readily and boils slightly; gives off arsenical vapours and forms a white incrustation on the cool part of the charcoal, and leaves a difficultly fusible magnetic slag ; with soda and borax yields with difficulty a bead of copper ; decomposed by HC1 or HNO 3 , forming a green solution and a jight coloured deposit. Comp. Sulpharsenide or sulphanti- monide of copper, with variable quanti- ties of silver, iron, zinc, and mercury ; the pale varieties contain a large propor- tion of arsenic usually; the darker varieties more antimony. Of the two following analyses of Cornish specimens a. was by Hemming, from Gwennap, b. by Michell, from Crinnis : a. b. Copper 48-40 ... 46'00 Arsenic ll'SO ... Antimony ... 21 '00 Iron 14-20 ... 17'20 Sulphur 21-80 ... 14 '00 Silica 5-00 ... Silver ... 1'80 Total 100-90 '.'.'. 100-00 The composition is so variable that it is difficult to give formulae, but with copper 50 "2 per cent., iron 17 '7, arsenic 11 '8, sulphur 20 '2, the composition might be written As 2Fe 5Cu 4S, or Cu 5 Fe 2 S 4 As ; with copper 46 '7, iron 16 '4, antimo D y 18 "0, sulphur 18 '9 it might be written Cu 5 Fe 2 Loc. Crinnis, and other mines near St. Austell, in large iridescent crystals (Figs. 33, 35, 38, 39, 40, 41); Botallack ; Levant ; Cook's Kitchen, Tincroft, Con- durrow, Tresavean, Carharrack, South Huel Basset, and other mines in the neighbourhood of Camborne and Red- ruth, formerly ; Trevaunance, St. Agnes; Huel Prosper ; Herodsfoot ; Tre- vascus, Trenance; Old Treburgett, St. Teath (Polytelite), Britannia and Prince Regent, North Molton ; Beeralstone ; Combemartin; Tavistock, &c. ; also Scot- land, France, Spain, Italy, Germany, Hungary, Mexico, &c. Obs. The largest crystals have mostly occurred at Crinnis and other mines near St. Austell. Fahlerz may be distin- guished from magnetite and hematite by inferior hardness ; from mispickel by its darker colour ; from chalcocite (copper glance) by supei'ior hardness and brittle- ness. The crystals may be distinguished from all other similar minerals except Tennantite by their form. Tennantite is probably only an arsenical variety of fahlerz. Perhaps analysis a. is Tennan- tite. The Polytelite from Old Treburgett contains a considerable proportion of silver. Angles. o o = 70 32' o a = 125 16' a a 90 00 od 144 44 on 160 32 dd 120 00 False Topaz. See Quartz. Felspar. This term, which is com- monly applied to a particular species (Orthoclase), is more properly a name for a group of nearly-related species, dif- fering from each other, however, in che- mical composition, crystalline form, and other characters. Dana says, "The felspar group is remarkable for its unity in crystallographic and all physical char- acters." The felspars are characterized by a sp. gr. below 2 '85 ; H. 6-7, or mostly scratched by a good knife ; fusi- bility 3-5 ; crystallization oblique or doubly oblique, with two easy and nearly perfect cleavages forming angles of 90, or nearly 90. In all, the cleavage planes have pearly lustre, and some varieties of several species exhibit an opalescence, or a play of colours, when viewed in cer- tain directions. They have been sup- posed to pass into each other by imper- ceptible degrees, and their chemical com- position would seem to favour this view, while the differences of crystalline form are not great enough to forbid the sup- position. Dana, however, considers the microscopic investigation of the felspars to be entirely in favour of the distinct- ness of the species. He remarks that oligoclase and orthoclase are often found 46 FELSPAR. FLUOR. together in granite, obsidian, and tra- chyte, and yet keep themselves distinct, even to microscopic perfection. This has silso been shown, by the Rev. Professor Hiughton, to be the case with albite and orthoclase in the granites of Cornwall and of Ireland. The chief species, according to Dana, are : O. ratio Cleavages. for RR 2 Si. Anorthite ... 94 10' & 85 50' 1.3.4 Labradorite. 93 20 86 40 1.3.6 Hyalophane 1.3.8 Andesite ... 1.3.8 Oligoclase... 93 50 86 10 1.3.9 Albite 93 36 86 24 1.3.12 Orthoclase.. 90 00 90 00 1.3. 12 The amount of silica increases with the increasing proportion of alkalies, from anorthite, which is usually without any alkali, to albite and orthoclase, with the protoxide bases solely alkaline. The following table, from Page's Hand- book of Geological Terms, exhibits the range of composition of the chief felspars : Sil. Alum. Pot. Soda. Lime. Iron Ortho. 61-70 15-20 7-14 1-4 1-3 1-2 Albite. 67-71 14-20 1- 4 7-11 1- 3 0-1 Labrad. 43-55 26-30 0-1 1-4 9-12 1-3 Anorth. 42-46 32-37 0-1 0-1 10-18 0-1 Oligo. 60-64 18-24 1- 3 2-10 2- 5 0-1 Only albite and orthoclase have, as yet, been found in Cornwall and Devon ; these are described under their respec- tive headings. Some of the foreign felspars are valu- able as ornamental stones, while the large deposits of kaolin or china clay, in Cornwall, Devonshire, and elsewhere, are the results of the decomposition of felspar, of granite, or perhaps other fel- spathic rocks. Felspathic. Containing felspar. Fibrous. A term applied to some minerals which occur in, or readily split into, fine thread-like portions, especially if somewhat elastic. Ex. Amianthus, Chalcotrichite, &c. Filamentary and Capillary are terms used with nearly the same meaning. Fibrous Brown Iron Ore. See Limo- nite. Fibrous Gypsum. See Gypsum (Satin Spar). Fibrous Red Copper Ore. See Cuprite (Chalcotrichite). Fibrous Tin Ore. See Cassiterite (Wood Tin). Figure Stone. See Agalmatolite. Filamentary. See Fibrous. Flaming. A method of testing some substances with borax or micro, in a bead before the blowpipe by rapidly blowing a strong and a weak blast alter- nately. This intermittent flame, with some metallic oxides, produces an opaque bead, when the ordinary treatment would give a transparent bead. Jx. Oxide of Zinc. Flexible. Capable of being readily bent. Flint See Quartz (Calcedony). Flints, apparently derived from chalk rock, are not uncommon in several parts of Corn- wall, as Ludgvan, Breage, and other places near the const, as well as all around the coast itself on the beach. They occur also on the high ground of the Land's End, and some parts of the Scilly Islands. Floatstnne. A peculiar vesicular va- riety of quartz found in some of the Cornish mines, and elsewhere. Fluate of Lime. See Fluor. FLUELLITE. Rhombic ; in very small pyramids, with their solid angles truncated, like Fig. 89, but without the planes v. ; trans- parent to translucent ; lustre vitreous ; white; H. 3'0. Comp. According to Wollaston, it contains fluorine and aluminium, but an analysis is much needed. Loc, Stenna Gwynn, St. Austell, with Autunite and Tavistockite, on a grey quartz rock. Sometimes incrusting small "vugs." Obs. It was discovered by Levy nearly 60 years ago, but has since been re-dis- covered by Mr. R. Tailing, of Lostwi- thiel. Most of the specimens yet dis- covered are in the British Museum, and it is intended soon to make a new analysis. The largest crystals are less than one- tenth of an inch long. Angles. e = 108' 00' e e' = 144 00' ee 109 04 FLUOR. [Fluor Spar. Cann. Blue John.] Cubical ; in cubes, octahedrons, and most of the forms from Fig. 1 to Fig. 32, also Figs. 53, 55, 58 ; with perfect octahedral cleavage ; also compact, nodu- lar,* granular, fibrous, or earthy ; brit- tle ; fracture conchoidal or uneven, but difficult to obtain in crystallized speci- mens ; transparent to opaque ; vitreous, splendant to glimmering ; colourless, white, blue, green, yellow, brown, purple, red, black; sometimes dichroic; or co- loured in layers, parallel to the faces of the simple crystal; exhibits fluorescence FLUOR. FLUORINE. 47 in a marked degree ; streak white or slightly tinted as the colour ; H. 4 ; G. 3-3 '2 ; pyro or f rictio-phosphoric. Var. Chlorophane is a compact, white, yellowish, or bluish variety, which is highly pyro-phosphoric, shining with ' a beautiful green light when mode- rately heated, especially if newly raised. Z?., etc. In matrass often decrepitates, sometimes changes colour, or phos- phoresces ; on C decrepitates, melts to an opaque white crystalline mass, colouring the flame dull red ; with gypsum melts to a transparent bead which is opaque on cooling; slowly soluble in HC1 or HNO 3 , giving off a g?.s (HF) which corrodes glass ; readily decomposed by warm H 2 SO 4 , giving off HF abundantly, and being converted into sulphate of lime. Comp. Anhydrous fluoride of cal- cium. No analysis of a British speci- men is known to the writer, but the usual composition is about 47 per cent, of fluorine and 53 per cent, of calcium, which would be represented by the for- mula CaF. 2 . LOG. Huel Spearn, Balleswidden, Spearn Moor, and other St. Just mines, but very scarce ; St. Michael's Mount ; Tremearne, in granite veins ; and Great Huel Vor, Breage, but very scarce ; Stray Park, Dolcoath, North Roskear, and other Camborne mines; East Huel Crofty, Carn Brea, East Pool (crystal- lized and amorphous " chlorophane," as- sociated with wolfram), and other mines in Illogan ; South Huel Buller, Cardrew Downs, Pednandrea (crystallized, in many colours, and amorphous "chlorophane"), North Huel Grambler (Figs. 1, 7, 9, 21, 23), Huel Sparnon, Huel Damsel, Huel Gorland, Huel Unity, Huel Unity Wood, and other mines in Redruth and Gwen- nap, in great variety of colour and form, also fibrous, concentric, or earthy ; North Downs ; Trevaunance, Huel Devonshire, and other St. Agnes mines, formerly in beautiful octahedrons made up of minute cubes, or in cubes with their edges modi- fied by one, two, or three planes, and other forms, like Figs. 1, 7, 21, 22, 23, &c. ; Huel Mary Ann (fine blue modified cubes, like Figs. 10, 21, 23, &c.), Huel Trehane, and Huel Trelawny (deep blue bevelled cubes, like Figs. 18, 21, 22, 23, &c.), Menheniot; Huel Maudlin, near Lostwithiel, in large semi-transparent octahedrons, with chlorite and calcedony ; South Caradon and West Caradon, St. Cleer, in colourless elongated cubes, and like Figs. 1 and 2 ; Stenoa Gwynn ; Holm- bush ; Huel Franco, Buckland Mona- chorum ; Virtuous Lady, and other mines near Tavistock ; East Tatnar Mine ; Beer- alstone (Figs. 1, 2, 8, 9, 16, 20, 21, 22, 23, 53, 55, &c.) ''The finest crystals are either colourless, or of a pale sea-green intern- ally, and upon the surface, or only the edges, of a rich smalt-blue, or a contrary disposition of the same col ours " (Greg and Lettsom, p. 24); also pale-green, translu- cent, or white and opaque octahedrons on hornstone ; also fibrous and compact, Fig. 53 shews part of a magnificent crys- tal from this locality which was in the collection of Professor Phillips. It is probably the most complete crystal of any mineral yet discovered. The foreign localities of fluor are almost every- where where tin, copper, or lead is mined. Obs. Fluor occurs massive in most of the copper mines and many of the tin and lead mines of the county, but is somewhat scarce in the extreme west. It occurs also in pseudomorphs at several localities (see Pseudomorphs). It is used as a flux in reducing iron and copper ores, hence its name from "fluo" to flow. " Cann," or " Kann," is a Cornish name ; Blue John a Derbyshire name. Chloro- phane has, as yet, been found only at East Pool and Pednandrea mines. Angles. o o r - 109 28' w a = 155 42 a a 90 00 wo 145 46 oa 125 16 xx' 166 57 dd 120 00 xx" 140 09 da 135 00 xa 152 04 fa 161 34 tt" 144 03 ff 126 52 tt' 162 15 mm 120 31 ta 150 48 ma 154 46 ag 147 00 ww' 167 47 ai 174 40 ww" 136 47 yy 177 00 Fluorescence. " This name has been given to the peculiar phenomenon exhi- bited by fluor spar, of transmitting one colour and reflecting another from a thin layer adjacent to the surface by which the light enters." (Bristow's Gloss, of Min., p. xvi.) Fluorine. This element, occurs in only a very few minerals, of which fluor is the chief. It may be readily detected in the fol- lowing manner : Heat a small portion of the assay, in fine powder, in a clean and dry matrass, and insert in the open end a small slip of Brazil-wood paper. If any fluorine be present the tube will be roughened and rendered opaque inside, and the paper will turn straw yellow. Other delicate tests are described in works devoted to blowpipe analysis. 48 FLUX. FEANGIBILITY. Flux. A substance added to a mineral to increase its fusibility, and sometimes to carry off one or more ingredients. The principal fluxes used in determinative mineralogy are carbonate of soda (soda), borax, microcosmic salt (micro.), fluor spar, cyanide of potassium, and boric acid. Foliated. A term applied to minerals which may be split into thin leaves. Ex. Mica. Foliated Arseniate of Copper. See Chalcophyllite. Form. Minerals which occur in defi- nite geometrical forms are said to be crystallized (see Crystallography). Those which are evidently made up of minute or imperfect crystals, the form of which cannot be made out, are said to be crys- talline. A considerable number of minerals are not known in the crystal- lized or crystalline state : these are said to be amorphous. Many amorphous minerals, as well as some that are known as crystals, occur sometimes in imitative forms. The chief of these are : a. Globular. When the shape is sphe- rical, or nearly so, as in some varieties of aragonite. When the spheres are small we have the pisolitic form ; when very small, the oolitic. b. Botryoidal. When the shape is nearly like that of a bunch of grapes. Ex. Malachite. c. Mammillary. In rounded promi- nences, less separated from each other than in b. Ex. Blistered Copper. d. Reniform. A form somewhat like that of a bullock's kidney. Ex. Some forms of iron pyrites. Nodu- lar is nearly the same. e. Stalactitic. Icicle shaped. Ex. Sta- lactite. f. Goralloidal. In form somewhat like masses of coral. Ex Some forms of aragonite (flos-ferri). g. Acicular. Needle-shaped. This is more often seen in distinctly crys- tallized specimens. Ex. Antimo- nite. h. Wiry. Ex. Native Silver. i. Dendritic. Mossy. Ex. Native Copper, j. Leafy. In thin plates. Ex. Native Copper. Formula. An abbreviated expression of the chemical constitution of bodies, in which the different elements present are represented by their symbols. An em- pirical formula states only the number of atoms of each element present. A " constitutional" or "rational" formula attempts to express something of the arrangement of those elements. Thus As 2 Co3H l6 O 16 is an empirical formula for Erythrite (Erythrine), while As,3CoSH 2 or (CO) 3 As.jpg + 8H 2 O or As 2 6 s Co" 3 + ! 8OH 2 are rational or constitutional for- mulae for the same mineral. Fracture. A term used for indicating the kind of surface obtained by breaking minerals. The chief varieties of fracture are : a. Conchoidal. Shell-like, with the broken surface shewing curved concavities somewhat like those on the inside of a cockle shell. Ex. Flint. b. Splintery. Ex. Serpentine. c. Hackly. The broken surface shew- ing a number of wire-like points. Ex. Native Copper. d. Uneven. Ex. Pyrites. e. Even. The specimen breaks with an even surface. It is distinguished from Cleavage by the fracture occurring indifferently in any direction, while cleavages are in certain defiuite directions. f. Earthy. This character may occur in combination with others. It is used when the broken surface is seen to be covered with minute irregularities without lustre. Ex. Chalk. Either of these terms may be qualified by the prefix sub. Thus, sub-conchoidal indicates an imperfect conchoidal frac- ture. Fracture must not be confounded with Cleavage, as many minerals exhibit both. In some minerals the cleavage is very perfect and easily obtained, while the fracture is scarcely to be at all ob- served. Ex. Mica, Blende, Galena, Calcifce, c. Francolite. See Apatite. Frangibility. A convenient term for including such characters as-- a. Brittle. When parts of the mineral separate in powder on attempting to cut it. Ex. Calcifce. b. Sectile. When thin pieces may be cut off with a knife, but the mineral pulverizes under the ham- mer. Ex. Chalcocite. c. Malleable. When slices may be cut off, and these slices may be flat- tened under the hammer. Ex. Native Copper. d. Flexible. When the mineral will bend, and remain bent after the bending force is removed. Ex. Native Copper. e. Elastic When the mineral, after being bent, will spring back to its original position. Ex. Mica. FREIBEKGITE. GALENA. 49 f. Friable. Crumbling ; easily crushed between the fingers. Pulverulent has nearly the same meaning. MX. Melaconite. The term Tenacity is sometimes used in the sense of Frangibility. Freibergite. See Fahlerz (Polytelite). French Chalk. See Steatite. Frictio-electric. Minerals which be- come electric, by rubbing are said to be "frictio-electric." Some are "positively" and some "negatively" electrified by friction. Ex. Tourmaline. Frictio-phosphoric. Minerals which shine with a peculiar light some what like phosphorus when rubbed are said to be " f rictio-phosphoiic. " Ex. Some varie- ties of Quartz. Fuller's Earth. This is said, by Garby, to have occurred in Cornwall, but no locality is given. Fusible. Capable of being melted. Minerals which cannot be melted before the blowpipe are said to be "infusible." Fusibility, Scale of. The following is Plattnerr's scale, which is adopted in this work : 1. Readily fusible to a bead. 2. With difficulty fusible to a bead. 3. Readily fusible on thin edges. 4. With difficulty fusible on the edges. 5. Infusible. The following is Von Kobell's scale, which is more definite, but not so easily obtained : 1. Autirnonite. 2. Natrolite. 3. Almandine or precious Garnet. 4. Actinolite. 5. Adularia. 6. Bronzite. G. GALENA. [Lead Glance. Galenite. Sulphuret of Lead.] Cubical ; in cubes, commonly modified by planes of the octahedron and rhombic dodecahedron (Figs. 1, 9, 10, 11, 12, 13, 14, 15, 16, 18, 24, 29, 57, 58, and other forms), \\ith perfect cleavage par- allel to a.; also massive, concentric, botryoidal, incrusting, disseminated ; drusy, granular, or compact ; brittle or sub-sectile ; fracture uneven, but not easily obtained in crystallized speci- mens ; opaque ; lustre metallic, often splendant ; lead grey to black ; some- times with an iridescent tarnish : streak black; H. 2'5; G. 7 '2-7 7. Var. Specular galena is a very bii.ht curved lamellar variety. Blue lead is a pseudomorphous variety, af er Pyromor- phite, which occurred at Huel Hope in 1822 and 1825, in hexagonal crystals ; it will burn in the flame of a candle when newly raised. Argentiferous Galena, or Silver Lead, is a name applied to varie- ties containing a notable quantity of silver. ft., etc. In matrass usually decrepi- tates, and yields a light coloured subli- mate with a strong heat ; in the open tube a white sublimate of sulphate of lead, and sulphureous odour ; on C some- times decrepitates, melts readily, and is easily reduced in RF to a malleable bead of lead, giving off SOg, and depositing a yellow incrustation on the charcoal. A minute grain of silver is often yielded by cupellation ; decomposed by HC1, if in fine powder ; more easily by HNO 3 . Comp. Anhydrous sulphide of lead, usually with some iron, and sometimes small quantities of antimony, zinc, cop- per, silver, &c. With lead 86 '55 per cent, and sulphur 13 '45 the formula may be written Pb's or PbSO^ or SO 2 Pbo". LOG. West Huel Darlington, Ludg- van, associated with silver ore and native silver ; Huel Alfred (with the finest crystals of Pyromorphite ever found in Cornwall), and Boiling Well, Phillack ; Binner Downs ; Huel Pool, Huel Rose, Huel Penrose, Sithney, with phosphate and arseniate of lead ; West Godolphin, Breage ; St. Michael's Mount, in small spots ; Huel Unity, Gwennap, with very fine crystals of ai seniate of lead ; Pol- dice, Tresavean ; Trevascus ; Huel Bas- set ; Dolcoath; North Roskear ; Huel Crofty ; Great Huel Baddern, East Huel Falmouth, Huel Jane, and other mines in Kea and Kenwyn ; Garras and South Garras, St. Allen; Budock Vean, Swan- pool, and other mines near Falmouth ; Huel Rose, East Huel Rose, Cargoll, South Cargoll, Newlyu ; Huel Golden, Huel Penhale, Trebisker Green (with native silver and silver ore), and other mines in Cubert ; West Chiverton ; Great South Chiverton ; North Chiverton ; Perran Huel Virgin ; Huel Mexico ; Huel Kayle ; Carclaze Tin Mine, in small specks ; Pentire Glaze (with very fine carbonate of lead), Endellion; Trebur- gett, St. Teath; Huel Ludcott (with silver ore and native silver), and Huel Wrey, St. Ive ; Herodsfoot, St. Pinnock ; Huel Mary Ann, Huel Trehaue, Huel Trelawny, and other mines in Menhe- niot ; Redmoor ; Holmbush ; Huel Lang- ford and Huel Brothers, Calstock. Huel Lee ; Huel Tamar ; East Huel Ta- mar ; North Huel Tamar ; Landkey ; Beer- alstone ; Hennock ; Combemartin ; Berry Narbor ; Devon and Courtenay ; Huel 50 GALMEI GAENET. Betsy; Huel Friendship; Bridford; Oke- hampton Consols, Holestock, and many other localities in Cornwall and Devon. Most metalliferous mines in Cornwall and Devon have yielded small specks of lead, but in the majority of the cases above referred to considerable quantities of lead ore have been raised. Argentiferous galena has occurred at the following mines, as well as others : Oz. of silver to the ton of ore. Beeralstone 80 to 120 South Hoo, a part of the same mine 140 Huel Betsy, Tavis- tock (about) 12 Huel Pool, Helston 60 about 1822 Garras Mine, near Truro 70 Huel Kose,Newlyn 60 to 65 Swanpool, near Falmouth Very variable. Obs. Galena occurs in almost every mining district where tin or copper is raised, but is, perhaps, most abundant in connection with limestone rocks. The lead ores raised in the two counties during the year 1869- mostly galena- amounted to 10,104 tons, which yielded 343,151 ounces of silver, or an average of nearly 34 ounces per ton. This is by far the richest raised in the United King- dom, except that of the Isle of Man, where the average is more than 40 ounces per ton. (See Min. Stat. for Great Britain, 1869, by Kobert Hunt, F.R.S.) Galena occurs in veins and feeds or irregular deposits, associated with py- rites, blende, limonite, chalcopyrite, ca- lamine, quartz, barytes, and calcite, and ores of gold, silver, arsenic, &c. It may be distinguished from argen- tite by its perfect cleavage and brittle- ness ; from graphite and molybdenite by its fusibility ; from dark varieties of blende by its dark streak and inferior hardness. Angles. 00 = 109 28' n n = 120 31' a a 90 00 na 144 44 dd 120 00 no 160 32 oa 125 16 mo 150 30 o d 144 44 ma 154 46 a d 135 00 Galmei. See Calamine. Gangue. The rocky material in which a mineral is embedded is called the gangue, or veinstone. Thus, the ordi- nary gangue of cassiterite is "capel," a hard compound of quartz, chlorite, and oxide of iron. GARNET. [Almandine. Colophooite. Melanite ; &c.] Cubical; usually in rhombic dode- cahedrons (Fig. 3), or in deltohedrons (Fig. 5), but often variously modified, as in Figs. 25, 26, 31, &c. ; one of the axes is often lengthened or shortened so as to distort the form ; sometimes macled ; the faces sometimes curved ; also mas- sive, compact, granular, lamellar ; very rarely a distinct dodecahedral cleavage ; usually tough, but massive varieties some- times friable ; fracture conchoidal or un- even ; transparent to opaque ; vitreous or resinous ; sometimes white, but more usually various shades of red, yellow, green, brown, or black ; streak un- coloured, except in impure and partially decomposed specimens ; H. 6 '5-7 '5 ; G. 3 1-4 -3. Var. The garnets are variously sub- divided, according to their chemical com- position and colour, as follows : a. Grossularite. A lime-alumina gar- net, of a light greenish colour. b. Pyrope. A magnesia-alumina gar- net. c. Almandite, or Precious Garnet. An iron-alumina garnet of a beautiful red colour. d. Common Garnet. An impure variety of the foregoing, of a brownish colour. e. Colophonite. A lime-iron-alumina garnet, of a yellowish colour. f. Spessartite. A manganese-alumina garnet. g. Aplome. A lime-iron-alumina gar- net, from Sweden, h. Andradite. A lime-iron garnet, i. Bredbergite. A Ifme-magnesia-alu- mina garnet, j. Ouvarovite. A lime-chrome garnet, of an emerald-green colour, k. Essonite. A lime-alumina garnet, of a reddish-yellow colour. 1. Melanite. A lime-iron garnet, of a black colour, &c. The specimens hitherto found in Corn- wall and Devon appear to be all either common garnet or colophonite. B. , etc.. In matrass unchanged on C the varieties containing much iron fuse at from 3 to 5 to a dark 'magnetic bead ; with borax or micro, gives the reactions for iron ; the powder is slowly decom- posed by HC1 more readily after fusion, depositing gelatinous silica. Comp. It is a complex anhydrous silicate of various bases. The range of composition in the various sub-species is very great, viz. : GEMS. GLAUCONITE. 51 Silica from 37'0 to 43'0 Alumina O'O 24'0 Peroxide of iron O'O 31 '3 Protoxide of iron O'O 39 '6 Lime O'O 371 Magnesia O'O 15'0 Oxide of manganese ... O'O 31 '0 Peroxide of chromium. O'O 24 '0 No analysis of a specimen from Corn- wall or Devonshire is known to the writer. Loc. Huel Cock Carn, Botallack, Crown's Rock, Chycornish Carn, and Roscommon Cliff (Figs. 3, 5, 25, 26, 31), from 1-16 th to one inch across, in the hornblende slate of the district, both crystallized and massive ; near Lewellin, embedded in carbonate of lime ; Cape Cornwall Mine, in a tin capel (Fig. 5) and macled, recently from l-10th to l-3rd of an inch ; Rose Moddress, a little west of Lamorna Cove, on a junction of granite and slate ; St. Michael's Mount ; Huel Trannack ; in greenstone between Camborne and Tuckingmill, near Dol- coath and North Roskear ; Carharrack ; near Copper Hill Mine, Redruth, with dark green epidote, very recently ; Seal Hole Tin Mine, St. Agnes (Fig. 3); near Lanlivery and Lostwithiel (black, crystallized, and massive, with magne- tite), specimens from this locality are wow IE. the Museum of the Royal Insti- tution of Cornwall ; Maudlin ; Terrace Hill Quarry, near Callington ; Lustleigh; Hay Tor ; Brent Tor ; on Dartmoor, in granite ; Belstone Consols, in large crys- tals, partly decomposed, &c. ; also Cum- berland, Ireland, Scotland. Obs. The Cornish garnets are asso- ciated mostly with greenstone, either in the rock itself, or in close proximity to it. Most of them are of a dull brown colour, and semi-transparent to nearly opaque ; some of the St. Just garnets formerly raised were of a light colour and resinous appearance. (Colophonite?) Angles. dd = 120 Off nn' = 131 48' nn 146 27 dn 150 00 Gems. These are such mineral speci- mens as are hard enough and have suffi- cient beauty of colour to be used as ornaments for the person. Fine speci- mens of Garnet, Beryl, Topaz, Tourma- line, and Quartz (rock crystals) are used for this purpose. With the exception of the rock crystals, or Cornish diamonds, few specimens of these minerals have been found in the two counties suffi- ciently good to be so used. Geodes. These are hollow stone balls, with the inner surface usually lined with crystals, some being occasionally de- tached. Very fine crystals are sometimes found so situated. Thus, some geodes of partially decomposed galena from Beer- f erris were found to contain fine crystals of anglesitc. GILBERT ITE. [Margarodite. Talcite. Nacrite. Hy- drous Muscovite.] Oblique (?), or more probably Rhombic ; usually in compactly aggregated scales ; friable ; translucent to opaque ; lustre pearly ; white, grey, yellowish, greenish ; H. 2-2 '5 ; G. 2 '6-2 '8. ., etc. In matrass gives off water ; on C alone becomes silvery white and opaque, but retains its lustre ; scarcely soluble in HC1 or HNO 3 ; more readily soluble in H 2 SO 4 . Comp. A hydrated silicate of alumina, containing small proportions of other bases. The following analyses of Corn- ish specimens indicate its composition ; a. by Lehunt, a whitish silky specimen, from a lode at Stenna Gwynn, St. Aus- tell ; b. by Thomson, ditto : Silica 4515 ... 47 ; 80 Alumina 4011 ... 32'62 Magnesia 1'90 ... 1'60 Lime 417 ... Soda ... 9'23 Protoxide of iron 2'43 ... 518 Water... 4'25 . 4'00 Totals 98'01 ... 100'43 Loc. Stenna Gwynn, St. Austell, with fluor ; Carclaze Tin Mine ; Tregoniog- hill and Tremearne, Breage, &c. Obs. It is often spoken of as a variety, species, or subspecies .f mica. It may, perhaps, be considered the crys- talline form of Kaolin. It is associated with the so-called china stone of Corn- wall. Girasol. See Quartz. Glance Cobalt. See-Cobaltite. Glance Copper. See Chalcocite. GLA UCONITE. [Green-earth. Kirwanite.] Amorphous, botryoidal, or massive ; earthy ; brittle, almost friable ; opaque ; dull or glim- mering ; various shades of green, bluish, or greyish ; streak somewhat lighter than the colour; H. 0-2; G. 2 '2-2 '4. B. , etc. In matrass yields much water and darkens ; on C fuses easily to a dark magnetic glass; partially soluble in HC1. Comp. Hydrated silicate of alumina and iron, with often some potash or soda. No analysis of an English specimen is known, but foreign specimens contain from 40 '0 to 52 '0 per cent, of silica, 5'0 to 12 '0 per cent, of alumina, 20 '0 to 25 '0 52 GLAUCOSIDEEITE. GOLD. per cent, of oxide of iron, O'O to 12 '0 per cent, of potash, and4'0 to 10 '0 per cent, of water. Loc. Huel Coates (botryoidal); Brans- comb cliff ; near Chard ; near Beer ; and generally throughout the grecnsavd of Devon. Also in many foreign localities. Obs. The term is applied very loosely to substances of very different composi- tion. Probably some of the so-called "green earth" is chlorite. The true Glauconite analysed by Thomson was from New Jersey, and contained 19 '0 per cent, of lime. Glaucosiderite. An old name applied to various kinds of Mica, and also to micaceous Vivianite. Glimmer. An old name for the various micas. GOETHITE. [Hydrous Oxide of Iron.] Rhombic ; in tabular crystals, like Figs. 124, 326, with some planes striated ; perfect cleav- age parallel to a (brachydiagonal); also acicular, capillary, or micaceous ; some- times botryoidal, fibrous, columnar, ra- diated, granular ; fracture conchoidal or uneven ; translucent on thin edges ; lustre sub-metallic ; adamantine, or silky; yellowish, reddish, or blackish- brown ; thin plates and fine needles red by transmitted light ; streak yellowish - brown; H. 5-5 "5; G. 4 1-4 '4. B., etc. In matrass gives off water; on C, in O F turns reddish, RF becomes black and magnetic ; infusible, or fusible with great difficulty on thin edges; with borax and micro, gives Fe reac- tions ; soluble in HC1, forming a yellow- ish solution ; often leaves a slight insolu- ble residue of silica. Comp. Hydrated peroxide of iron. The following is an analysis by Yorke of a specimen from near Lostwithiel, the sp. gr. of which was 4 '37 : Peroxide of iron 89 '55 Oxide of manganese 016 Silica 0'28 Water ... 10 '07 Total lOO'OG With 90 '0 per cent, of peroxide of iron and 10 '0 per cent, of water the formula may be written FegHg or Fe. 2 O 2 Ho 2 , Loc. Botallack, and other St. Just mines, like Fig. 124, and in doubly pointed flattened prisms, with some of the faces striated, rough, or mamtnilated ; Tincrof t ; Cam Brea ; Huel Druid ; Huel Beauchamp ; Huel Buller ; Restormel, in geodes (Figs. 124, 126, and other forms); Tintagel ; Delabole ; Exmoor, &c. ; also in Somerset, Scotland, Ger- many, Russia, and many other foreign localities. Obs. It usually occurs in veins and cavities, with quartz and limonite, of which it is, perhaps, a crystallized variety. It may be distinguished from specular iron (hematite) and magnetite by its yellowish streak, and by yielding water when heated in a matrass ; from rutile and brookite by its blowpipe reactions. Angles. M M' = 94 52' k k = 144 (XX dd' 130 40 a b 90 00 The form a d M p s has occurred at Botallack ; the forms a d p, a d m p d M p s, d M p, a d M p e u r, d M p b, adMpe, adMps, adMpes, adMpeslz, &c. , are from Restormel ; some were not less than two inches long. GOLD. [Native Gold.] Cubical, in cubes, octa- hedrons, rhombic dodecahedrons, r Redruth ; Tincroft, Carn Brea, Dolcoath, East Pool, and other mines in Illogan and Camborne ; Botal- lack (Fig. 223), with aragonite ; Boscas- well ; Parknoweth ; Huel Owles ; Carn- yorth ; Huel Bellon ; Huel Maggot ; Hennock, near Chudleigh ; Lustleigh ; Birch Tor Mine, near North Bovey ; and other localities in Devon. 56 HEMIHEDEAL. HYPEESTHENE. Micaceous Iron Ore Restormel ; Carn Brea ; Tincroft ; Huel Druid ; Levant ; Little Rounds ; and other localities Kidney Iron Ore and Red Hematite Botallack, Levant, and most of the St. Just Mines ; Huel Rave and Huel Rose, near Helston ; Treluswell, near Penryn, with magnetite ; Ladock, near Gram- pound ; Davidstow ; Birch Tor Mine, near North Bovey ; Lustleigh ; Buckfast- leigh ; Hennock, near Chudleigh ; and several places on Dartmoor ; Huel Forest, near Okehampton ; Bratton Fleming, Shirwell ; East Down ; Viveham, George- ham, and other places near Barnstaple ; Orleigh Court, near Bideford, forming a breccia with chert and flint in greensand ; in greensand at Buckland Brewer ; II- fracombe ; Combemartin ; Lynton ; West Down ; North Moulton ; Brixham, &c. Red Ochre Ladock ; Davidstowe ; and many other of the above-named localities. Red Chalk Little Bounds, St Just ; Ladock ; and Broad Down, Farway, near Honiton ; Peak-hill, near Sidmouth. The chief forms of Hematite are found in most mining districts. Obs. Hematite may be distinguished from goethite and limonite by its being anhydrous ; from these ores and magne- tite by the colour of its streak. The earthy varieties, however, often yield a little water when heated in a matrass, and sometimes have a brownish streak. Angles. RR' = 93 50' uu = 143 07' R o 122 30 u o 158 35 Hemihedral. A term applied to crys- tals which have only one-half of their planes developed. Thus, the tetrahedron (Fig. 33) is the hemihedral form of the octahedron (Fig. 1). If equal slices were to be taken from each alternate face of the octahedron until four of the faces were entirely destroyed, the resulting figure would be the tetrahedron, Hemitrope. A made. Hepatic. Liver-like. A term applied sometimes to a peculiar form of mineral, when it has much the same meaning as reniform, and also to a peculiar colour observed in some minerals. Thus, some varieties of pyrites readily decompose to a liver-coloured mass. HISINGERITE. [Thraulite.] Amorphous; massive and reniform, or compact in concentric crusts ; with rough surfaces ; brittle ; fracture conchoidal or uneven ; opaque ; lustre resinous, inclining to adamantine ; brownish or bluish-black ; streak yellow- ish-brown or pale reddish-brown: H. 3'5-4; G. 174-3. B., etc. In matrass yields much water with an acid reaction ; on C alone fuses with difficulty to a reddish, steel- grey, or black magnetic bead ; with borax and micro, gives Fe reactions ; partially soluble in HC1 or HNO 3 , leav- ing a gelatinous residue of silica. Com.}). Hydrated silicate of iron. The proportion of silica varies from 27 '0 to 36 '0 per cent., proto-peroxide of iron 44-0 to 53-0 per cent., water 10 '0 to 21 '0. A mean of three analyses of a Cornish specimen (sp. gr. 1"74), by Professor Church, gave Peroxide of iron 52"94 Silica 3614 Ph osphoric anhydride trace Magnesia trace Water 10'49 Total 99*57 With peroxide of iron 50 '6, silica 38 '0, water 11 '0, the formula might be written Fe 2 2Si2H. 2 or Fe. 2 O 3 2SiO 2 + 2H 2 O (oxygen ratio = 3.4.2). LOG. Cornwall (Huel Gorland?), on Autunite ; also on iron pyrites, in cavi- j ties, with Limonite, Vivianite, and Cron- | stedtite, probably from another locality. Obs. It was obtained from Mr. Tailing in the first instance, by Professor A. H. Church, who identified it, it having been mistaken for Beraunite. Holohedral. A term used in opposi- tion to "hemihedral," which see. Hornblende. See Amphibole. Horn Lead. See Cromfordite. Hornstone. See Calcedony. Horseflesh Ore. See Erubescite. Hydrate. A compound of an oxide with water, or a metal with hydroxyl. Thus the hydrate of the oxide of copper (cupric hydrate) may be written CuOH 2 as a compound of oxide of copper with water ; or CuH 2 O 2 or CuHo 2 , in which it is looked upon as a compound of cop- per with hydroxyl. Hydrated. Containing water as a con- stituent part, and not merely as external moisture. Water which is given off at a temperature above 100 C is usually con- sidered to be water of hydration. Hydrofluoric Acid. See Fluorine. Hydrous Oxide of Iron. See Limo- nite and Goethite. HYPERSTHENE. Oblique ; crystals usually imperfect and imbedded, when perfect usually somewhat like Fig. 160 (Pyroxene, with which Hypersthene is isomorphous); one perfect cleavage, often curved, or ICELAND SPAE. INDURATED. 57 striated ; another at right angles, im- perfect ; fracture uneven ; translucent to opaque ; lustre vitreous or resinous, usually pearly or sub-metallic on cleav- ages ; grey, green, red, yellow, brown, black ; streak white or grey : H. 4-6 ; G. 3-2-3U Var. 1. Hypersthene proper has very dark colours, and often a greenish-grey strpak ; H. 6 ; rather readily fusible. 2. Bronzite colours dark, and inclin- ing usually to brown ; white streak ; H. 5-6 ; almost infusible ; often brittle. 3. Diallage. Colours usually light ; white streak ; H. 4 ; often easily fusible. 4. Hypersthene rock, Diallage rock, Gabbro, &c., are names given to rock masses, composed largely of some form of hypersthene, with a great deal of fel- spar, as in the cliffs at Coverack Cove and the boulders on Cronsa Downs. ., etc. In matrass no change ; on C alone usually fusible to a dark magnetic globule, or enamel ; with soda and borax gives the reactions for iron, and some- times those of manganese ; insoluble in HC1 or HN0 3 . Comp. Anhydrous silicate of magne- sia, iron, arid lime ; bat of very variable composition. Loc. Coverack Cove (Bronzite?), Ky- nance Cove (Diallage?), and other parts of the Lizard district; St. Cleer (?). Hypersthene occurs in Scotland, Nor- way, Sweden, Italy, North America, &c. Obs. Hypersthene should, perhaps, be included with pyroxene and amphi- bole, in one large group, only separable into sub-species. The chemical composi- tion seems to be in all, too variable to serve as a means of classification in species, and they are isomorphous with each other. I. Iceland Spar. See Calcite. ILMENITE. [Manaccanite. Titaniferous Iron. Ti- tanite. Iserine. Kibdelophau, &c.] Hex- agonal ; in tabular crystals, somewhat like Figs. 200, 20], and 230, but with curved faces ; or drusy ; also massive, granular, or disseminated ; brittle ; f i ac- ture conchoidal or uneven ; opaque ; lustre metallic or sub-metallic, brilliant to glimmering; iron-black, brown, or steel-grey ; streak reddish-brown to black ; sometimes slightly magnetic ; H. 5-6; G. 4-6-5-0. Var. a. Ihnenite occurs crystallize 1 or massive. b. Manaccanite was a term given to the grains of titaniferous iron-sand found at Manaccan. c. Iserine is the term applied to a dark sand of similar composition, fouud at Iserweise, in the Kiesengebirge. .B., etc. In matrass unchanged ; on C unchanged, or turns brown ; with micro, or borax gives the reactions for Ti; the fine powder is slowly soluble in concen- trated HC1 ; the concentrated solution will, after a time, yield a precipitate of titanic anhydride after dilution and boiling ; imparts a blue colour to H 2 SO 4 if boiled in it. Comp. An anhydrous compound of the oxides of titanium and iron. Of the following analyses of Cornish specimens a. was by Klaproth, b. by Gregor, c. by Lampadius : a. b. c. Oxide of titanium... 45 '25 45 '00 43 '5 Oxide of iron Sl'OO 46'00 50'4 Oxide of manganese 0*25 trace 0'9 Silica 3'50 trace 3'3 Alumina 1"4 Total 100-00 91-00 99'5 With 48 '0 per cent, of titanic anhydride and 52 '0 per cent, of ferric peroxide the formula may be Ti 2 Fe 2 or Ti 2 O 3 -HFe 2 O 3 or TiFeO 3 . Loc. Manaccan, in the bed of a rivu- let, as a black sand ; Gwendra, near Coverack, disseminated, in diallage rock ; Lannarth, near St. Keverne, in a stream as a dark sand ; recently at Porthalla, in a ferruginous deposit, both massive and crystallized. The crystals were len- ticular, with curved faces, and varying from l-10th to i of an inch in diameter. Obs. It may most readily be distin- guished from Hematite by its dark brown streak and reactions with micro. Incandescent. Glowing ; combustion without flame ; when charcoal is heated before the blowpipe it glows, but rarely bursts into flame. This is incandescence. Incrustation. A term applied to the dep-sit which is formed on the cool part of a charcoal or tire-clay support when ores of arsenic, antimony, or lead are heated. It may always be driven away by directing the blowpipe flame on the part, and in this manner may be easily distinguished from the white ash left by the combustion of some varieties of char- coal. Indigo Copper. See Covellite. Indurated. Hardened. Talc, Kaolin, and other minerals seem sometimes to be greatly hardened wnen iu contact 58 INFUSIBLE. JAMESONITE. with igneous rocks, as if baked. They | are then said to be indurated. Infusible. That which cannot be fused j or melted. Minerals are said to be in- j fusible if they cannot be fused by means ! of an ordinary blowpipe flame, although I they may be mostly fused by using the j oxy-hydrogen blowpipe. Investing. A term applied to minerals which occur spread in a thin coating over the surface of some different kind of mineral or rock. Iridescent. Exhibiting colours some- thing like those of a rainbow. Iridescent Copper Pyrites. See Chal- copyrite (Peacock Copper). Iris. See Quartz. Iron Flint. See Quartz. Iron Glance. See Hematite (Specular Iron). Iron Mica. See Hematite (Micaceous Iron Ore). Iron Nickel Pyrites. See Pentlandite. Iron Ochre. See Hematite and Limo- nite. Iron Pyrites. See Pyrites. Iron Rutile. See Goethite. Iron Spar. See Chalybite. Isomorphism. " Similarity in crystal- line form exhibited by substances of similar chemical constitution." Thus the following mineral carbonates crystal- lize in forms having a very great resem- blance to each other, all being hexagonal, and their primary or cleavage rhombohe- drons having faces similarly inclined to to each other, and varying only from 105 03' to 107 9 54' : Calcite CaC0 3 = 105 '03 Dolomite (MgCa)CO 3 10615 Diallogite MnCO 3 106'51 Chalybite FeCO 3 107 '00 Mesitine Spar (FeMg)CO 3 10714 Magnesite MgCO 3 107 '25 Calamine ZnCO 3 107 '54 A similar group of isomorphous carbo- nates, crystallizing in the rhombic sys- tem, is the following, the angles being those of the prisms : Aragonite CaCO 3 = 116 10' Cerussite PbCO 3 117 14 Strontianite SrCO 3 117 19 Witherite BaCO 3 118 30 Similar groups of isomorphous minerals are known in each system of crystalliza- tion, when it is found that there is a ten- dency for one member of a group to take the place of another in a compound, thus leading to a passage from one to another. In fact, it seldom happens that one member of an isomorphous group is quite free from traces at least of another. For further information on this interesting subject see the works of Mitscherlich ; Frankenheim's Systeme der Krystalle ; or Brooke and Miller's Elementary In- troduction to Mineralogy, 1852. ISO PYRE. Amorphous ; compact ; brittle ; frac- ture conchoidal or uneven ; translucent on thin edges, or opaque ; lustre vitreous or dull; greyish or velvet-black, some- times with reddish spots ; streak pale greenish-grey; H. 5 '5-6 '5; G. 2 '9-3; slightly magnetic. ., etc. In matrass not changed ; on C fuses readily to a magnetic globule, sometimes colouring the tip of the flame greenish ; with borax and micro, gives Fe reactions ; imperfectly decomposed by HC1 or HNO 3 , leaving a deposit of silica ; the powder is decomposed by strong solution of carbonate of potash. Comp. Anhydrous silicate of iron, alumina, and lime (?). The following analysis of a specimen from St. Just was made by Turner : Peroxide of iron 20 '07 Alumina 13'91 Lime 15'43 Oxide of copper 1'94 Silica . . 47-09 Total 98*44 Loc. Huel Carne, St. Just, in masses of several inches in length, in granite, associated with Cassiterite and Tourma- line ; it is also said to have been found near St. Ives. Obs. In appearance it is not unlike Obsidian, but less lustrous. It has been thought to be an impure variety of opal or jasper. J. Jade. A substance which has some- times been so named is described as Saussurite, which is itself perhaps only a variety of Pyroxene. See Saussurite. JAMESONITE. Rhombic, usually in aggregations of imperfectly formed acicular prisms, with a perfect basal cleavage at right angles to the prismatic faces ; or fibrous, co- | lumnar, or massive ; sectile ; opaque ; 1 lustre metallic ; dark steel grey ; streak black, or very dark; H. 2-2 %5; G. 5 '5-5/8. Var. Feather ore is a variety which occurs in soft masses, with interlacing fibres, like felt. B., etc. In matrass decrepitates, and 1 yields a reddish or yellowish sublimate ; i on C fuses at 1 to a dark mass, which is partly absorbed by the charcoal ; deposits JASPER. KALINITE. 59 a yellow incrustation ; may be en- tirely volatilized in O F, except a little infusible slag, which gives Fe or Mn re- actions ; in EF yields, after a good deal of blowing, a malleable bead of lead ; decomposed by warm HC1, leaving a white ppt. Comp. It is an anhydrous sulphide of lead and antimony. The following analy- ses, by H. Rose, are all of Cornish spe- cimens : a. b. c. Lead 4075 40'35 3871 Antimony 34 '40 33 '47 34 '90 Sulphur 2215 nt. det. 22 '53 Iron 2-30 2'96 2'65 Copper 013 0'21 019 Zinc... , trace 074 Total 9973 9972 "With lead = 43 '6, antimony 36 '2, and sulphur 20 '2, the formula might be writ- ten Pb 3 Sb 4 S 9 or 2PbS Sb 2 S 3 + PbS. Loc. Near Padstow ; Port Quin Cliffs, and Trevinnock, near Endellion, with bleinierite ; Port Isaac, Pendogget, Huel Lee, Calstock ; Huel Boys ; Tintagel ; found also in Spain, Hungary, Siberia, Brazil, &c. Obs. It usually occurs with other ores af antimony. It may be distingished from antimonite by its basal cleavage, yel- low incrustation when heated on charcoal, and by its yielding a bead of Pb in EF. JASPEE. Amorphous ; tough ; fracture conchoi- dal, uneven, or splintery ; opaque ; lustre resinous or dull ; sometimes white, but more usually grey, yellow, red, brown, green, or black, sometimes mot- tled of various colours ; streak white or slightly coloured; H. 6-7; G. 2'6-3'0. Var. a. Eibbon Jasper has the colour arranged in stripes, or bands. b. Lydian Stone, Tin Flint, Touch- stone, or Basanite, is of a velvet-black colour, and has a flat conchoidal fracture. It is sometimes placed with Calcedony. c. Bloodstone seems tobe partly Jasper and partly Calcedony. It is of a dark green colour, spotted with red. d. Eisenkiesel, or Iron Flint, is a brown and somewhat earthy variety. B., etc. In matrass unchanged, or gives off a little water ; on C infusible ; with soda fuses readily to a coloured bead, with much effervescence ; insoluble in HC1, HN0 3 , or H 2 SO 4 . Comp. Anhydrous silica. It usually contains, however, a small proportion of water, and a variable proportion of per- oxide of iron, and other oxides. Loc. Botallack, Huel Owles, Levant, Cape Cornwall, Huel Spearn, Little Bounds, Huel Stennack, and other mines in St. Just, of various colours, as red, black, green, &c. ; Ding Dong, Madron ; Marazion Beach ; Looe Bar ; Tremearne ; North Eoskear, Dolcoath (red and black); Eedruth; Huel Unity; St. Austell; Tru- goe ; Huel Maudlin ; in greensand at Buckland Brewer ; Ivybridge ; Doddis- combleigh; Blackdo wn -hills ; Brent Tor; Okehampton ; near Exeter ; Haldon, near Teigiimouth, pale red; and many other places in the two counties. Very fine masses of Jasper are obtained from Egypt, Italy, Germany, &c. Obs. It can only be regarded as an impure mixture of crystalloid and colloid silica, with various metallic oxides. Por- celain Jasper, or Porcellanite, is of quite a different composition ; it is simply a greatly hardened (baked?) clay. Jaspery Iron Ore. A siliceous variety of Hematite, or a very ferruginous Jasper. JOHANNITE. [Uran-VitrioL] Oblique; in small flattened prisms, reniform masses, or druses ; transparent to opaque ; lustre vitreous ; emerald or yellowish-green ; streak pale green; taste bitter and astringent ; H. 2-2 '5 ; G. 319. B. , etc. In matrass yields water with acid reactions, and turns brown ; on C is fusible at first, but leaves finally a dark infusible residue ; with borax and micro, gives the reactions for Uranium ; slightly soluble in H 2 O. Comp. Hydrous sulphate of Uranium. Loc. Johannite has, perhaps, occurred at South Huel Basset, in transparent, bright yellow crystals, with other ores of Uranium. (See Trans. Eoy. Geol. Sc. Corn., vol. vii., p. 86.) The true Johan- nite occurs in Germany and the United States. Obs. It is probably a product of the decomposition of the ores of Uranium. Its solubility in water would of itself account for its rarity in a wet county like Cornwall. KALINITE. [Alum. Potash Alum.] Cubical ; crys- tals usually like Figs. 1, 2, 3, or com- binations of these ; generally in crusts, fibrous masses, or as an efflorescence ; fractnre conchoidal or uneven ; trans- parent or translucent; colourless, white, or slightly tinted with green, yellow, or blue ; streak white ; taste sweetish- astringent ; H. of compact specimens 2-2-5; G. 175-1-9. 60 KAMPYLITE. KEKATE jB., etc. In matrass melts at first, yields a large quantity of water with acid reaction ; on C the same, and gives off SO 2 ; the white residue becomes blue if treated with Co ; soluble readily in water. Comp. Hydrated sulphate of potash and alumina. "With sulphuric anhydride 3376, alumina 10 '82, potash 9 '95, water 45 '47, its formula may be written A1 2 2K 43 + 24H a or S 4 O 8 Ko 2 Al 2 o vi + 240 H 2 . Loc. It is said to occur in clay at Chudleigh, in Devon (Greg'and Lettsom, p. 71). Obs. It is extracted from shales in large quantities in Yorkshire, near Whitby, and other places. Kampylite. See Mimetite. Kann. See Fluor. Kaolinite. Dana. Rhombic, appear- ing as hexagonal scales under the micro- scope. Perhaps may be found in the Cornish and Devonshire Kaolins. KAOLIN. [China Clay, Lithomarge, &c.] Amor- phous ; massive, in beds, veins, or disse- minated ; should, perhaps, be regarded rather as a rock than a mineral ; fracture earthy ; sectile, brittle, or friable ; opaque ; dull ; adherent ; unctuous or plastic while moist, sometimes meagre when dry ; white, grey, or bluish, yel- lowish, brownish, &c., from various impurities ; streak like colour : H. 1-3 ; G. 1-8-27. Var. a. China Clay is the pure white variety, used for thebest kinds of pottery. b. Lithomarge is a peculiar indurated variety, with H. 2-2 '5 : G. about 2 '6 ; sometimes pyro-phosphoric. c. Carnat is a flesh-coloured variety, containing a good deal of iron. B. etc.. In matrass gives off water ; on C is infusible, and often loses colour; trente-1 with Co turns blue; not readily decomposed by HC1 or HNO 3 . np. Hydra ted silicate of alumina, with very often potash. Of the following analyses a. was from Breage, analysed T>y Dr. B.ase; b. from St. Stephens, dittu ; c. from Devon, hy Berthier ; d. from Dartmoor, by Fownes : a. b. c. d. Silica 4015 39 55 50 '51 47'20 Alumina 3S'20 38 '05 3818 38'80 Peroxide of iron trace Magnesia 175 1'45 0'24 Potash & loss 9-50 870 176 Water 11 -65 12'30 11 "02 12'00 Total 99-23 100D5 9971 100130 e. is the analysis of a specimen from Devonshire ; f., from Dartmoor; g., a kaolin earth from Plympton ; h. , a yel- lowish-white lithomarge, with peach- coloured veins, from Cook's Kitchen, by Reeks (Trans. Roy. Geol. Soc. Corn., vol. vii., p. 76): e. f. g. h. Silica 44-26 44'25 40'9 48'3 Alumina 38'81 36'81 44'5 36'4 Peroxide of iron 0'8 Lime & potash 2 '20 Water 1274 1270 15'3 14'5 Total 95-81 95'96 1007 100.0 With silica 46 7, alumina 41 1, water 12 '2 the formula may be written 2A1 2 3Si + 3H 2 or 2(Al 2 3 SiO 2 ) + SiO 2 + 3H 2 O or Si 3 (Al 2 o vi ) 2 -i-3OH 2 . Loc. a. China Clay Balleswidden, and other St. Just mines ; Tregoning- hill, Breage; Vogue, near St. Day; East Huel Damsel; St. Stevens and St. Den- nis, Carclaze, and many other places near St. Austell ; Chy tane, St. Enoder ; Cligga Head, St. Agnes ; Great Dowgas ; Bovey Tracey ; Dunscomb-hill, near Sidmouth ; Plympton ; Fownes ; on Dartmoor ; and ' many other places in Cornwall and ! Devon. b. Lithomarge Balleswidden, and i other mines at St. Just ; near St. Ives ; | Cook's Kitchen, Tin croft, Dolcoath, Cam | Brea, and other mines near Camborne ; Huel Druid ; Huel Basset ; West Basset ; South Huel Frances ; Carharrack ; Ting Tang ; West Huel Jewell ; St. Blazey ; | in amorphous yellow masses with agate | at Hay Tor ; with apatite and tourma- line at Bovey Tracey. Obs. Kaolin is a substance of immense importance in the arts. In an impure form it probably composes all the clays of the earth's crust, and when indurated | forms xlates and shales. It should rather be described as a rock than a mineral. Kassiterite. See Cassiterite. KERA TE. [Kerargyrite. Horn Silver.] Cubic; in small modified cubes, octahedrons, or rhombic dodecahedrons (Figs. 1, 2, 3, 8, to 16); sometimes acicular, columnar, massive, or investing ; sectile or mallea- ble ; fracture conchoidal . or uneven ; translucent to almost opaque ; resinous or waxy ; pearl-grev, greenish, bluish, or brown, especially on exposure to light ; streak white and shining ; H. 1-1-5; G. 5-3-5-6. jB., etc. In matrass melts without further chanae ; on C fuses readily, and is easily reduced to a malleable bead of KILLAS. LEPIDOLITE. 61 silver ; if mixed with oxide of copper tinges the flame bright blue ; if moist- ened and rubbed on a plate of polished iron, metallic silver is deposited ; insolu- ble in HC1 or HNO 3 ; slowly soluble in ammonia, and re-precipitated by HC1. Comp. Anhydrous chloride of silver. Pure specimens contain 75 '34 per cent, of silver and 24 '66 per cent, of chlorine, the formula will therefore be AgCl. Loc. Huel Herland ; Huel Alfred and Huel Ann, Phillack ; Huel Duchy, in brown gossan, in forms resembling Figs. 8 and 12 ; Huel St. Vincent, near Cal- stock, with native silver ; Silver Valley ; Huel Brothers ; Huel Mexico and Huel Basset, Perranzabuloe, crystallized and massive ; Dolcoath ; North Dolcoath (Figs. 1, 8, 12); Botallack, Levant; found also in Ireland, and in many foreign silver producing districts. Obs. In Cornwall it usually occurs with other ores of silver, hydrous oxide of iron, quartz, and ores of copper. Mr. Came observes, "It has not yet occurred in any Cornish mine whose lode traverses granite." (Trans. Roy. Geol. Soc. Corn., vol. vii., p. 87.) Angles. Same as Cuprite. Killas. A Cornish term for the al- tered clay-slate of the district. Klinoclase. See Clinoclase. Kupferindig. See Covelline. Kupfernickel. See Niccolite. Lamellar. Minerals which can be split up into plates are so called. Ex. Barytes, Fluor, &c. Foliated is the same, but the plates are very thin. LANGITE. Rhombic ; crystals usually small and short, in forms not unlike those of ara- gonite ; also fibro-lamellar, concretion- ary, or investing ("rippled"); the surface sometimes earthy; transparent or translucent ; lustre of crystals vitre- ous, of thin crusts silky ; colour blue or greenish-blue ; H. 2 '5-3, crusts softer ; G. 3-48-3-5. B., etc. In matrass gives off water with acid reaction, and turns black ; on C gives off a sulphureous odour, and easily yields a bead of copper; soluble in HC1. Comp. Hydrated basic sulphate of copper. The following analyses are all very recent : a. b. c. d. e. f. Sulphuric anhydride 16 '42 1677 1679 1672 16'88 16'2 Oxide of copper .. 65-82 65'92 67'48 67'31 67 '88 681 Lime 0'83 0'5 Magnesia 0'29 Water .. 18'32 16'19 1573 16'25 15'53 15 '2 Total 100-56 lOO'OO 100-00 100-28 100-29 lOO'O a. is an analysis by Maskelyne, b. by Pisani, c. by Church, d. and e. by War- rington, f. by Tschermak. With sul- phuric anhydride 16 '4, oxide of copper 65 '2, and water 18 "4 the formula may be written 4Cu, s", 5H 2 or CuSO 4 +3CuH 2 O 2 + 2H 2 O or SO 2 Cuo"3CuHo 2 + 20H 2 . Loc. Copper Hill Mine and Huel Bas- set, Redruth ; East Pool, Dolcoath, and other mines near Camborne. U bs. It is found on killas, in brilliant minute macled crystals of a beautiful deep blue colour, or "rippled" crusts of a greenish-blue tint and somewhat earthy appearance. The name Devilline was at first given to a very similar mineral. (See Comptes Rendus for 1864, pp. 813, 633 ; see also Journ. Chem. Soc., II., iii., 87; Phil. Mag., IV., xxiii., p. 306, 1864; Phil. Mag., IV., xxii., p. 473, 1865 ; Chem. News, x., 263, 1864, &c.) Lapis Ollaris. See Steatite (Potstone.) Lazurite. See Chessylite. Lateral. This term is applied to the secondary axes in the pyramidal and hexagonal crystallographic systems. Lead Earth. A term applied to the earthy variety of Cerussite. Lead Glance. See Galena. Lead Ochre. See Plumbic Ochre. Lead Spar. See Cerussite. Lenticular. Lens-shaped. Crystals which are nearly flat circular scales, but slightly convex above and below. Ex. Some specimens of Hematite and Ilmenite. Lenticular Arseniate of Copper. See Liroconite. LEPIDOLITE. [Lithia Mica.] Rhombic; rarely In prisms, with perfect basal cleavage ; usu- ally in pinkish granular masses, inter- spersed with small flexible translucent scales ; lustre pearly ; peach-blossom red to pearl-grey, white, or brownish ; crys- tals dichroic; H. 2'3; G. 2 '8-3. /?., etc. In matrass scarcely altered; on C fuses more or less readily to a trans- parent and nearly colourless glass ; colours flame red, especially if just mois- tened with HC1 or H 2 SO 4 , or mixed with KHSO 4 ; insoluble in HC1, HNO 3 , or H 2 SO 4 , but readily decomposed by HC1 after ignition. 62 LEPIDOMELANE. LIBETHENITE. Gomp. Anhydrous silicate of alumina, iron, potash, and lithia, with some flu- oride. Of the following analyses of Cornish specimens a. is by Turner, b. and c. are by Rammelsberg, d. is a recent analysis by Haughton, of a white, pearly specimen, from Tremearne, in Breage, which occurred in rhombic tables of 60 and 120: a. b. c. d. Silica 50-82 5170 52'40 47 '60 Alumina 21 '33 26 76 26 '80 27 '20 Protoxide of iron . . 9'08 Peroxide of iron .... 5 '20 Oxide of manganese trace T29 T50 T20 Lime 0'40 0'45 Magnesia 0'24 trace Potash 9-86 10'29 914 10"48 Soda 1-15 0-72 Lithia 4'05 T27 4'85 114 Fluorine 4 '81 7'12 418 Fluosilicon 5 '68 Phosphoric anhy. .. 016 Total 99-95 100"38 98'87 99'67 Loc. St. Michael's Mount, in pale peach-coloured and silvery hexagonal scales ; Trewavas Head and Tregoning- hill, Breage, in white rhombic scales ; Lanarth, near Redruth, nearly white ; near Bovey Tracey, in white silvery plates, &c. ; it occurs also in Scotland, Ireland, and many foreign localities. LEPIDOMELANE. Rhombic ; in six-sided plates, or rhombs of 60 and 120, with perfect basal cleavage ; flexible and elastic ; translucent or opaque ; lustre sub-me- tallic, adamantine, or vitreous ; dark brownish or greenish-black ; dichroic ; streak greenish ; H. 3'0 ; G. 3'0. B. , etc. In matrass no change ; on C melts readily to a dark magnetic globule ; with borax forms a greenish glass ; de- ed by HC1, leaving pearly silica. Gomp. Silicate (with fluoride) of alu- mina, iron, potash, and lithia. Of the following analyses a. is a Cornish speci- men (brown), by Turner ; b. a very dark coloured specimen from Cam Bosavern, recently analysed by Professor Haughton, F.R.S.: 27-06 Silica 40-06 Alumina 22'90 Protoxide of iron . . ) Peroxide of iron . . . . j Oxide of manganese .. 179 Lime Magnesia .. 1'07 Potash 4'30 .. 976 Soda .. 0'99 Lithia 2'00 .. 171 Fluosilicon . . 3'04 Fluorine 271 . b. 39-92 22-88 15-02 2-32 1-40 0-68 Total 100-82 . . 987 It will be seen that lepidomelane differs mainly from lepidolite by the smaller quantity of silica, and the presence of a large proportion of iron. Loc. Carn Bosavern, St. Just, and many of the Cornish granites. LEUCOPYRITE. [Arsenical Pyrites. Lolingite, &c.] Rhombic ; the usual combination is much like Fig. 115, without the plane O ; one perfect cleavage ; more usually massive ; compact, granular, or columnar; some- times disseminated ; brittle ; fracture uneven ; opaque ; lustre metallic ; sil- very-white to steel-grey, often a yellow or brown tarnish ; streak greyish-black ; H. 5-5*5; G. G-9-7'4. B. , etc. In matrass gives an abundant white or yellowish sublimate, which is dark and metallic below ; on C fuses readily to a black magnetic mass, depo- siting a white incrustation, and giving off copious arsenical fumes ; with borax gives Fe reactions ; insoluble in HC1 ; soluble in HNO 3 , with a separation of As 2 3 . Gomp. Arsenide of iron, with a little S, and sometimes Ni and Co. No analy- sis of a British specimen is known to the author, but foreign specimens yield about 30 '0 per cent, of iron and 70 "0 per cent, of arsenic. With iron = 32 '6 and arse- nic 73'5 the formula will be FeAs 2 . Loc. East Pool, Dolcoath, and pro- bably many other Cornish mines. It occurs largely in Norway and Germany. Obs. It has been usually mistaken for mispickel, from which it may be distinguished by its small proportion of of sulphur and its greater sp. gr. It not unfrequently contains paying quantities of gold and silver. LIBETHENITE. [Phosphate of Copper.] Rhombic ; mostly in small crystals, like Fig. 139 ; also globular, reniform, radiated, or com- pact masses ; brittle ; fracture conchoi- dal or uneven ; translucent on thin edges ; lustre somewhat resinous ; olive or black- ish-green ; streak olive-green ; H. 4 ; G. 3-6-3-8. B., etc. In matrass gives off water, turns black, and often decrepitates ; on C fuses to a dark globule of metallic ap- pearance ; in R F with soda yields a bead of copper, sometimes a slight alliaceous odour; soluble in HC1 or ammonia, still more readily in HNO 3 , forming a blue solution ; decomposed by KHO, the solution when neutralized with HNO 3 yields a pale yellow ppt. on addition of solution of nitrate of silver. LIME URANITE. LIMONITE. 63 Comp. Hydrated phosphate of cop- per. Specimens from Libethen, in Hun- gary, yield about 66 '5 per cent, of oxide of copper, 29 '7 per cent, of phosphoric anhydride, and 3 '8 per cent, of water. With these proportions the formula may be written Cu 3 P 2 4-CuH 2 or 3CuO, P 2 O 5 + CuH 2 Oo or P 2 O. 2 Cuo" a + CuHo 2 . Loc. Gunnislake, Callington, form- erly, with gozzan, qiiartz, and pyrites ; it was also found at South Huel Frances and some of the Gwennap mines (?), by the late Mr. John Garby. Its chief foreign localities are Hungary, Germany, the Ural, South America, &c Obs. This species is isomorphous with Olivenite, and the phosphoric anhydride is often partially replaced by arsenic an- hydride. Angles. M M' = 92 20' s e = 149 06' Ms 135 53 ee' 70 08 s s' 120 56 Lime Uranite. See Autunite. LIMONITE. [Brown Hematite. Hydrous Oxide of Iron, &c.) Amorphous ; maramilated, botryoidal, reniform ; fibrous, radiating, or concentric ; compact, earthy, or fria- ble ; stalactitic, &c. ; brittle ; fracture conchoidal, uneven, or earthy ; opaque ; lustre sub-metallic, resinous, silky, or dull; brown, to yellowish or black; streak yellowish -bro wn ; H. 5-5 '5, except ochre and umber, which are often less thanl; G. 3 '4-4. Far. a. Brown Hematite is a reni- form variety, with sub-metallic or silky lustre, and concentric fibrous structure. It is sometimes called Kidney Iron. b. "Wood Hematite has bands of yellow and brown alternately. c. Stilpnosiderite is a black or very dark brown variety, with conchoidal fracture and splendant lustre. d. Bog Iron Ore, Meadow Iron Ore, or Ochrey Brown Iron Ore, is a soft variety, often found in swampy places in mining districts. e. Yellow Ochre is a yellowish, earthy, or friable variety. f . Brown Umber is an impure, friable, brown-coloured variety. B., etc. In matrass gives off water and turns darker ; on C infusible, turns dark, and magnetic ; very thin splinters may sometimes be melted with great difficulty ; with borax and micro, gives iron reactions ; soluble in warm HC1, forming a yellowish solution ; of ten leaves a portion of silica undissolved. Comp. Hydrated peroxide of iron. Of the following analyses a. is of a Corn- ish specimen, by Yorke; b. and c. are recent analyses of massive specimens from Perran ; d. is a rusty -yellow stalac- titic specimen from Botallack, by Prof. A. H. Church (Journ. Chem. Soc., II., iii., 214):- t ^ a. b. c. d. Peroxide of iron 8216 58 '77 75 '04 7373 Oxide of manga- nese 3-08 2-65 Alumina 0'69 0'42 Lime 6-39 Oil Magnesia 0'26 012 Phosphoric an- hydride 113 6-99 1-54 Silica 2-42 8'01 718 Water 14'28 14'87 12'02 24'40 Total 98-99 99'06 99'08 9813 This last specimen is considered to be a distinct species by Dana, on account of the large proportion of water. With 811 per cent, of peroxide of iron, and 18 '9 per cent, of water the formula might be written Fe ? 2H 2 or Fe 2 O 3 +2H 2 O or Fe 2 OHo 4 . With peroxide of iron = 85 '6 per cent., and water 14 '4 it may be written 2Fe 2 O 3 + 3H 2 O or Fe 4 O 3 Ho 6 . Loc. Botallack, and the St. Just mines generally, in most of the varieties ; Huel Mary, and other mines in Lelant ; St. Ives Consols ; Great Work; Huel Rose, Sithney ; Constan- tino; St. Keverne; Trumpet Consols, and other mines in Wendron ; Huel Her- land ; Carn Brea ; Tincroft (Stilpnoside- rite and other forms); Camborne Vean ; Ting Tang, Huel Fortune, and other Gwennap mines ; North Downs ; Huel To wan, South Huel To wan, and several other St. Agnes mines ; Perranzabuloe ; Ladock ; Charlestown United, Ruby and Knightor, and other mines near St. Aus- tell, in several forms; Huel Maudlin (Stilpnosiderite and other varieties); Restormel Royal Iron Mines; Retire, Withiel, and other places in Cornwall ; Five Acre, Huel Prosper, Parkins, Sharp- ham, Torbay, and other iron mines near Brixham; Gymton, near Paignton; Smallacombe and Hatherly, Ilsington; Shaugh, and other places near Plympton ; Combemartin (umber, yellow ochre, &c.); Buckf astleigh ; Huel Robert, Sampf ord Spiney ; Huel Betsey, near Tavistock ; Copper Hill Mine, near Okehampton ; on Exmoor ; East Down and Viveham, near Barnstaple ; Buckland Brewer, near Bideford ; Ugbrook Park, near Chud- leigh (umber); and many other places in the two counties. 64 LINAEITE. LONCHIDITE. Bog Iron Ore Marazion ; Perran Con- sols, in 1839, light yellowish-brown to black ; " The light yellow ore appears to have formed around, and enclosed, some of the roots of the heath." (W. M. Tweedy, Rep. Roy. Inst. Corn., 1839.) Obs. It occurs in small quantities in almost every metalliferous mine in the world, except those worked in quartz rock. LINAEITE. [Cupreous Sulphate of Lead.] Oblique, with one perfect cleavage ; brittle ; frac- ture conchoidal ; translucent ; lustre vitreous to adamantine ; deep azure blue ; streak pale blue; H. 2 '5-3; G. 5 '3-5 '45. B., etc. In matrass gives off water with acid reaction, and loses colour ; on C fuses to a pearly globule ; in RF is easily reduced to a malleable bead, de- positing a yellow coating on the char- coal, and yielding sulphureous odours; with borax, alternately RF and OF, yields a grain of copper ; decomposed by HN0 3 , leaving a white residue of sulphate of lead, and forming a bluish solution. Comp. The hydrated sulphate of lead with copper specimens from Leadhills yielded to Thomson and Brook nearly 757 of oxide of lead, 19 '8 of oxide of copper, and 4 '5 of water. The formula may therefore be written PbS + CuH 2 or PbSO 4 +CuH 2 O 2 or SO 2 Pbo" + CuHo 2 . LOG. Very small specimens were found by Dr. C. Le Neve Foster at Huel Pen- rose, Sithney, about the year 1866. It occurs also in Cumberland, and at Lead- hills, in Lanarkshire. Obs. The crystals from Cumberland are not much unlike Figs. 148, 149, 151. The Cornish specimens were not crystal- lized distinctly. LIROCONITE. [Octahedral Arseniate of Copper. Len- ticular Arseniate, &c.] Rhombic or oblique ; in obtuse faintly striated double pyramids, like Fig. 165 ; crystals usually minute, but have been obtained formerly as much as one inch in length ; some- times in granular masses, but more rarely so than crystallized ; sectile ; fracture conchoidal or uneven ; trans- lucent ; vitreous to resinous ; sky-blue to verdigris-green ; streak pale blue ; H. 2-2-5; G. 2-8-3-0. B. t etc. In matrass gives off much water and turns dark green ; on C alone deflagrates (?), fuses readily to a dark slag containing granules of copper; de- posits a white incrustation on the char- coal at a considerable distance from the assay ; with soda, after well roasting, yields a malleable bead of copper ; easily soluble in HNO 3 ; decomposed when in powder by solution of KHO, leaving a black powder of oxide of copper. Comp. Hydrated arseniate of copper. Of the following analyses of Cornish spe- cimens a. was by Wachtmeister, b. by Hermann, c. and d. by Damour : Oxide of copper 3773 36 : 38 3718 37 : 40 Alumina 8 '61 10 '85 9 '68 10 '09 Peroxide of iron 3 '66 0'98 Arsenic anhy- dride 22-29 23-0522-2223-40 Phosphoric an- hydride 3-87 3-73 3-49 3 '24 Water 23 "84 25 '01 25 '49 25 '44 Total 100-00 100-00 98-06 99*57 The sp. gr. of b. was 2 '985, of d. 2 '964. With oxide of copper 36 "61, alumina 11 '87, arsenic anhydride 26 "59, and water 24*93, the formula might be written 8Cu2As 2 Al 2 + 24H 2 or (CuO) 3 As 2 O 5 + Al 2 O 3 As 2 O 5 + 5CuHoO 2 + 19H 2 O or 2As 2 O 2 Cuo" 3 + Al a Ho 6 + 2CuHo 2 + 19OH 2 . Loc. Huel Muttrell, Huel Gorland, Huel Unity, Gwennap, many years since ; Great Hewas United, and Gun- nislake more recently, but not such fine specimens. It is also said to have oc- curred at Huel Providence, Lelant. Obs. It occurred always associated with other arseniates of copper. Its beautiful colour is sufficient to distin- guish it from them all. Angles. MM' = 119 20' oo = 107 38' Lithia Mica. See Lepidolite and Lepi- domelane. Lithomarge. See Kaolin. Loadstone. See Magnetite. Localities. A complete list of Cornish and Devon localities, topographically arranged, will be found in Part I. of this book. In the case of minerals indicated with type as follows : FLUOR or JASPER, only the localities of the best specimens, or those remarkable for their situation, will be given ; in other cases the author has given all the localities known to him. Foreign localities are indicated, with the greatest conciseness, so as to shew the wide distribution of many minerals which are commonly supposed to be almost exclusively Cornish. Of this, Cassiterite is a noteworthy example. Lonchidite. A peculiar variety of marcasite which formerly occurred at Cook's Kitchen and Tincroft mines, in crystals resembling Fig. 152. LUNNITE. MAGNESITE. 65 LUNNITE. [Phospliorocalcite. Pseudomalachlte. Ehlite.] Oblique (?) or Khombic? reni- form ; massive ; fibrous ; surface drusy ; brittle ; fracture small conckoidal or un- even ; translucent or sub-translucent ; lustre adamantine or vitreous ; dark green ; streak light green ; H. 4 '5-5 ; G. 4-4 '4. B., etc. Like Libethenite. Comp. Hydrated phosphate of cop- per. The following is an analysis by Heddle ; the sp. gr. of the specimen was 4'25 : Phosphoric anhydride 22 '73 Oxide of copper 6813 Water 8'51 Silica 0'48 Total 99-85 LOG. " Only one specimen of this substance has hitherto been found in Great Britain ; it is from Cornwall, and in Mr. Greg's collection. Colour verdi- gris-green ; translucent by transmitted light. Consists of minute globular con- cretions, not very closely compacted." (Greg and Lettsom, Manual of Miner- alogy, p. 324.) Foreign specimens have occurred in Germany, Hungary, and Siberia. Fig. 167 represents a foreign specimen. Angles. O e = 146 18' f f = 117 49' ge 168 46 Lustre. The reflection of light from the surface of a body occasions what is called its "lustre." The following are the chief varieties observable in minerals : a. METALLIC. Ex. Pyrites, Galena. b. ADAMANTINE. Ex. Diamond. c. VITREOUS. Ex. Crystallized Quartz. d. RESINOUS. Ex. Some varieties of Cassiterite. e. PEARLY. Ex. Pearl Spar. f. WAXY. Ex. Kerargyrite. g. SILKY. Ex. Fibrous Carbonate of Iron. Each of these kinds of lustre may exist in several degrees: as "splendant," "brilliant," "shining," "glimmering." When no lustre is observable the speci- men is "dull." The various kinds of lustre are also qualified by the prefix "sub." Thus many varieties of dark mica have a "sub-metallic " lustre. The true metallic lustre is only ob- servable in minerals which are perfectly opaque. The silky lustre is usually ob- servable in minerals which have a fibrous structure; while the pearly lustre is j often seen in minerals having a foliated or lamellar structure, and usually occurs on the cleavage planes. M. Made. Twin Crystals, " Macles," or "Hemitropes" are groups of two or more crystals, which appear as if mu- tually intersecting each other, or as if a single crystal had been cut in two, one part turned round a certain number of degrees, and then re-united to the other. Thus, if the octahedron Fig. 54 a., Plate III. , be cut in two in the direction of the dotted line, the one-half rotated 90, and then re-united to the other, a made like Fig. 54 b. will be the result, as in many crystals of Spinel, Alum, and other minerals. Of course, such a divi- sion and re-union has not really taken place ; the whole crystal has pi'obably taken the peculiar form from its first formation. The corresponding axes of macles are always inclined to each other, in accordance with very precise laws. Made. See Andalusite (Chiastolite). Macro-diagonal. The greater of the lateral axes in the rhombic system, also a plane parallel to this axis and the principal. MAGNESITE. [Carbonate of Magnesia.] Hexagonal; in rhombohedrons ; with perfect rhom- bohedral cleavages, forming angles of 72 31' ; also massive ; compact, reni- foim, earthy ; tough or friable ; fracture conchoidal or earthy ; transparent to opaque ; lustre vitreous ; shining to dull ; colourless, white, yellow, brown, or black ; streak lighter than colour ; H. 4 '5-5, except earthy varieties ; G.2 - 8-3'l. ft., etc. In matrass no change, or loses colour ; on C infusible, loses colour, becomes alkaline; turns reddish with Co ; soluble with effervescence in HC1, HN0 3 , or H 2 S0 4 . Comp. Anhydrous carbonate of mag- nesia. Pure specimens contain Car- bonic anhydride 51'62 per cent., mag- nesia 48 "38. With this composition the formula may be written MgC or MgCO 3 or COMgo". LOG. From veins of serpentine in the Lizard district (impiu-e). "An amor- phous mineral of snowy whiteness, and occasionally pulverulent, from West Grambler, has been pronounced to be carbonate of magnesia, but hitherto this fact has not been confirmed." (J. Garby,. 66 MAGNETISM. MALACHITE. Trans. Hoy. Geol. Soc. Corn., VII., 81.) Found also in Norway, Germany, India, &c. 06s. It usually occurs in serpentine districts. It may be distinguished from calcite by its solubility in H 2 SO 4 , and by its behaviour when treated with Co. Magnetic Iron Ore. See Magnetite. Magnetism. A property possessed by many minerals containing iron, and in a less degree by those containing Ni and Co, especially after heating on C. MAGNETITE. [Magnetic Iron Ore. Oxidulated Iron.] Cubic ; usually in modified octahedrons or rhombic dodecahedrons, &c. (Figs. 1, 2, 3, 8, 10, 14, 15, 29, &c.); often macled ; also compact, granular, lamellar, disse- minated, or earthy ; brittle ; uneven or conchoidal ; opaque ; lustre metallic or sub-metallic ; splendant to dull ; iron- black or dark brown ; streak like colour ; H. 5 '5-6; G. 4-9-5-2; magnetic, espe- cially when massive. B., etc. In matrass no change, or turns red ; on C infusible, or fuses with very great difficulty, and often loses its magnetism somewhat ; with borax gives Fe reactions ; soluble in warm HC1 or HN0 3 . Comp. Anhydrous proto-peroxide of iron. A pure specimen contains of prot- oxide of iron 35 '03, peroxide of iron 68-97, or iron 72 '41, oxygen 27 '59. With this composition the formula may be written FeFe. 2 or Fe 3 O 4 or Fe 2 O 2 Feo". LOG. Botallack, Crown's Rock, and the cliffs near by, massive, in bands or veins, with garnets, hornblende, axinite, epi- dote, and other rare minerals, also as a black magnetic sand ; St. Michael's Mount ; the Lizard, in hornblende ; Gvvinter, in diallage rock ; Trelus- well, near Penryn, with green chlo- rite ; Tresavean, massive, in chlorite ; near Redruth, crystallized ; Huel Jane, Kea ; St. Agnes, in slate ; Huel Maud- lin ; Lanlivery, with pyrites and garnet ; Roche ; Fowey Consols, with chalcopy- rite and francolite ; St. Stephens ; Buckland-in-the-Moor, near Ashburton ; Haytor, with hornblende and felspar ; Hatherby, near Ilsington ; South Brent ; near Tavistock ; in veins at Lundy Island, &c. ; found also in Scotland, Ice- land, Norway, and many foreign locali- ties, in large quantities. Obs. Massive magnetite may be dis- tinguished from hematite by its black streak ; crystallized specimens may be distinguished by form alone. Angles. The same as in Cuprite. oo = 109 28' dd = 120 0(K a a 90 00 &c. MALACHITE. [Green Carbonate of Copper.] Oblique ; crystals minute, and like" Figs. 155, 156, 157 ; perfect cleavage parallel to M ; usually massive, globular, reniform, bo- tryoidal, mammillated, stalactitic; com- pact, fibrous, or earthy ; brittle ; frac- ture sub-conchoidal or uneven ; translu- cent to opaque ; lustre adamantine or vitreous ; often dull ; various shades of green ; crystals dark green ; globular ! masses usually banded in concentric : layers of different shades ; streak light green; H. 3 "5-4; G. 3 '7-4. -B., etc In matrass gives off water and turns black ; often decrepitates ; on I C infusible and turns black ; in RF ! yields a globule of Cu ; more readily | on addition of soda ; with borax yields Cu reactions ; soluble with effervescence in HC1 or HNO 3 (dilute), forming a i blue solution ; slowly turns ammonia I blue. Comp. Hydrated carbonate of copper. ! Pure specimens yield nearly 71 '91 per cent, of oxide of copper, 19 '90 per cent. of carbonic anhydride, and 8 19 per cent. of water. With these proportions the formula may be written CuC 4- CuH 2 or CttCOg+CuHjO, or COCuo" + CuHo 2 . Loc. Botallack, Huel Cock, Huel Edward, Huel Speed, and other mines in St. Just ; Huel Alfred, Phillack ; St. Michael's Mount, in small specks; West Godolphin, Breage ; Mullion ; various parts of the Lizard district, with native copper ; Dolcoath and other Camborne mines ; Huel Buller. Huel Basset, South Huel Basset, and other mines near Red- ruth ; Huel Gorland, Ting Tang, Car- harrack, and many other mines in Gwen- nap ; Huel Husband ; West Huel Vir- g'n; Huel Music; Huel Mexico: Hewas; uel Harmony ; Lanescot ; Pentire, in acicular crystals ; Phoenix ; Gunnis- lake ; Buckfastleigh ; Hennock, near Chudleigh ; ComKemartiu, and other places in Devon, in small quantities. Obs. Malachite occurs in small quan- tities in the older workings of almost all the copper mines of the two coun- ties. The crystals are usually found lining cavities in the massive specimens. It maybe distinguished from chrysocolla by its superior sp. gr., hardness, and abundant effervescence, and ready solution when treated with dilute HC1. MALLEABLE. MATEASS. 67 Angles. M M' = 123 35' M e = 112 33' OM 90 00 ee 107 16 OT 90 00 Malleable. Capable of being beaten into thin plates. Ex. Gold, Silver, Copper. Malleable Copper. See Native Copper. Mammillary. See Form of Minerals. Manganese Spar. See Rhodonite. MANGANITE. [Grey Oxide of Manganese.] Rhom- bic ; in prisms vertically and deeply striated (Fig. 110); often grouped in bundles, with perfect brachy diagonal cleavage ; also massive, fibrous, radiat- ing, compact, granular ; brittle ; fracture uneven ; translucent on thin edges to opaque; metallic or sub-metallic, often splendant ; dark steel-grey to iron-black ; streak brown or black ; H. 3 '5-4 ; G. 4 '2-4 '4 ; perfectly conducts electricity. B., etc. In matrass gives off H 2 O ; on C is infusible ; with soda, borax, and micro, gives Mn reactions ; soluble in warm HC1. Comp. Hydrated manganic peroxide. Pure specimens yield 89 '90 per cent, of peroxide of manganese, and 10*10 per cent, of water. With this composition the formula will be Mn 2 H 2 or Mn 2 O 3 H 2 O or MngOsHog. LOG Botallack, in brilliant crystals ; Huel Bucketts ; Veryan ; Indian Queens, near St. Columb ; Trebartha ; St. Min- ver, well crystallized ; Lettcott ; Lanli- very; Restormel (acicular); Upton Pyne, near Exeter (well crystallized); Doddis- combleigh, near Chudleigh ; in North Devon ; in West Devon, in sandstone. The mineral occurs well crystallized in Scotland, Ireland, and in many foreign parts. 06-5. It may be readily distinguished from Pyrolusite by its lustre and hard- ness ; from the ores of copper and anti- mony by its inf usibility. Angles. M M' = 99 40' k k = 103 24' MO 90 00 MARCASITE. [White Iron Pyrites.] Rhombic; in modified prisms (Figs. 150, 151, 152, &c.); often macled; crystals usually striated, sometimes rough ; often stalactitic, bo- tryoidal, reniform, radiating ; brittle ; fracture uneven ; opaque ; lustre metal- lic, splendant to dull; pale yellow, greenish, greyish, often a brown tarnish ; streak dark greenish-grey j H. 6-6 '5 ; G. 4-6-4-9, Far. a. Cocks-comb Pyrites is a macled variety, which occurs in forms resem- bling Fig. 152. b. Lonchidite is a similar variety, con- taining a little (2 to 6 per cent.) arsenic. It is tin-white, greyish, or greenish -grey. c. Hepatic Pyrites is a partly decom- posed variety, of liver-brown colour. B. , etc. In matrass gives a deposit of S ; on C melts readily to a dark magne- tic bead, gives off a sulphureous odour ; insoluble in HC1; soluble in strong HNO 3 , leaving a deposit of S. Comp. Anhydrous sulphide of iron. The following analysis of a specimen of Lonchidite from Cook's Kitchen is by Platnner : Sulphur 4961 Iron 44-23 Arsenic 4'40 Cobalt 0-35 Copper 075 Lead 0-20 Total 99-54 With iron 46 '67 per cent., sulphur 53 '33, or the same as ordinary iron pyrites, the formula may be FeS 2 . Loc. Cook's Kitchen and Tincroft (Lonchidite), on brown iron ore and py- rites ; Huel Unity ; Creegbrawse ; Huel Clifford ; Huel Rose, Newlyn ; Fowey Consols ; Huel Crowndale ; Huel Cre- bor (Lonchidite, in at tie heaps); Vir- tuous Lady Mine, aggregated crystals, very large, on quartz ; Combemartin ; Tamar Mines, near Beerferris (formerly in hexagonal prisms, pseudo after cal- cite); found also in Cumberland, Scot- land, Ireland, and many foreign locali- ties. Obs. It is best distinguished from Pyrites by its crystalline form, paler colour, and greater liability to sponta- neous decomposition. Margarodite. See Gilbertite. Marmolite. See Serpentine. Martial Arseniate of Copper. See Scorodite. Martial Pyrites. See Pyrites. Massive. Regular structure, but no distinct external form. Matrass. A small vessel of glass with a bulb blown at one end ; a bolt head ; a simple tube closed at one end, used in the testing of minerals by the aid of heat. Two such tubes may be made from a piece of glass tube about four inches long and one-sixth wide, by softening the centre in a gas flame or candle flame, with the aid of a blowpipe, and then pulling the ends asunder. For the method of using such tubes sea Blowpipe Reactions. 68 MEAGEE. MESSOLITE. Meagre. Minerals which feel soft and rough are so called ; the word is used in centra-distinction to harsh (hard and rough) and unctuous (soft and smooth). MELACONITE. [Black Copper Ore.] Amorphous ? cubic ? oblique ? usually massive, pul- verulent, earthy, or investing ; friable ; opaque ; dull ; dark grey to black ; streak black and shining, or dull ; soils the fingers ; H. below 1'5(?) G. 5 '2. Var. "Melaconite crystals from Corn- wall, collected by Mr. Tailing, have been described by Maskelyne as 'monoclinic,' ' basal cleavage easy,' . . 'often twins,' . . 'H. a little above 4; G. 5-825-827; Church has ascertained that the crystals are essentially pure CuO.' It would appear . . that this oxide of copper is trimorphous." (Dana, Syst. Min., 1868.) B., etc. In matrass usually gives off some water ; on C is reduced to mallea- ble copper where it touches the support ; pure specimens are easily reduced to a bead ; with borax or micro, gives Cu re- actions ; with soda an indication of Mn is often obtained ; soluble in HC1 or HNO 3 , forming a green solution ; slowly soluble io ammonia, forming a deep blue solution. Comp. Anhydrous oxide of copper, often containing silica, manganese, and a little water. Pure specimens contain copper 79 '85 per cent., oxygen 2015 per cent. With these proportions the for- of 97 39' and 82 21' , with perfect basal cleavage ; usually botryoidal, reniform, stalactitic, pulverulent, incrusting, or massive ; brittle; conchoiflal or uneven; ! translucent to opaque ; vitreous ; various j shades of green, with a yellow or brown ! tarnish ; streak white ; H. 2 ; G. 1'8- ' 1'9 ; taste metallic and inky. B., etc. In matrass fuses, swells up, and gives off water, which reddens blue litmus paper, leaving a yellowish infusi- ble residue ; on C the same ; gives off | SO. 2 ; finally turns red and magnetic ; with borax gives Fe reactions ; soluble in H 2 O, forming a pale green solution, which gives a rust-coloured precipitate with ammonia. Comp. Hydrated sulphate of iron. Pure specimens yield 2719 percent, of i oxide of iron, 31 '02 percent, of sulphuric | anhydride, and 41 '79 per cent, of water. j With these proportions the formula may | be written FeS-f 7H 2 or FeSO 4 + 7H 2 O | or SO 2 Feo"-t-7OH 2 . Loc. Huel Prosper, in irregular nodu- | lar or semi-crystalline masses ; St. Agnes ; ! Ting Tang ; United Mines ; Fowey Con- | sols, Huel Maudlin ; and the old work- ' ings of many other mines in Cornwall, in ! small quantities. Found also in similar circumstances in most mining districts. Obs. It is probably produced by the decomposition of pyrites or marcasite. Distinct and well-formed crystals seldom occur in nature. Menaccanite. See Ilmenite. mula will be Cu or CuO. Loc. Botallack, Huel Speed, and other St. Just mines ; Huel Trenwith ; Huel Providence ; Marazion Mines ; West Godolphin ; Great Huel Vor ; Great ! Huel Fortune; Huel Herland ; Relis- tian ; Tresavean ; Ting Tang ; Huel J Jewell ; United Mines ; Huel Basset ; I Huel Buller ; Huel Trefusis ; Dolcoath ; Tincrof t ; Huel Seton ; Great St. George, < Perranzabuloe ; Pembroke ; East Crin- nis ; Fowey Consols; Gunnislake; and in small quantities in most of the copper mines of the two counties, with other ores of copper, of which it is, perhaps, a decomposition product. It occurs in copper mines and gozzans, under similar circumstances, all over the world. Obs. It may be easily distinguished from wad, asbolane, and pyrolusite by its yielding a bead of copper on C before the blowpipe. From pitchblende by the same reaction, and by its softness. MELANTERITE. [Copperas. Green Vitriol. Sulphate of Iron.] Oblique ; in prisms, with angles MESOLITE. [Harringtonite. Antrimolite. Mealy Zeolite.] Anorthic (?); two perfect cleav- ages 88 and 92 ; in acicjAar aggrega- tions, the crystals always inacled ; in divergent groups ordelicsrte tufts, lateral planes being indistinct^ striated; also massive, fibrous, columnar, drusy, com- pact, porcellanous, &c., fragile; tough when amorphous ; transparent to opaque ; lustre vitreous or silky; white, colour- less, greyish, yellowish; H. 3 '5-5 '5; G. 2-2-4. Var. a. Antrimolite is a variety ; with H. 3-5-4; G. 2-21. b. Harringtonite has H. = 5 '25 ; G. 2-21 ; it occurs massive, earthy, and tough. B., etc. In matrass gives off much water ; on C becomes opaque, if not so already ; swells up into a vermicular mass, and fuses to a blebby enamel; de- composed by HC1, depositing gelatinous silica. Comp. Hydrated silicate of lime, alumina, and soda. The composition of METEORITE. MIMETITE. 69 the Irish, Scottish, and foreign speci- | mens hitherto analysed is from 45 '0 to 49'0 per cent, of silica, 25 '0 to 28'Oper ; cent, of alumina, 5 '0 to 11 '0 per cent, of lime, 4'0 to S'O per cent, of soda, and 10 '0 to 13 '0 per cent, of water. Loc. The rocks between Botallack and Huel Cock, with axinite and natrolite, as a mealy deposit ; Stenna Gwynn. It , occurs also in Ireland, Scotland, Iceland, and many foreign localities. Obs. It is usually associated with vol- canic rocks. Meteorites. A meteorite of 231bs. weight fell at Stretchley, in the parish of Ermington, about 12 miles from Ply- mouth, in the year 1623. (Trans. Devon. Assoc. , vol. III. ) Another meteorite fell at Menabilly, Cornwall, in 1791. (Greg andLettsom, p. 246.) Mica. This term, which was formerly | applied to almost all minerals which could be split into thin foliss, is now made use of only as a convenient term for a group of complex mineral silicates having many properties in common. a. They are all characterized by a per- fect and easily obtained basal cleavage ; so that they are readily reduced to thin, tough laminae, with usually a pearly or sub- metallic lustre. b. Potash is almost always present among the protoxide bases, and alumina among the peroxides. c. The crystallization is either rhom- bic or hexagonal, the angle formed by any two adjacent prismatic faces being 120. The Micas described in this Handbook are Gilbertite, Lepidomelane, Lepidolite, Muscovite. Micaceous Iron Ore. See Hematite. Micaceous Uranium Ore. See Autu- nite and Torbernite. Microcosmic Salt. This very useful salt, a phosphate of soda and ammonia, is largely used in the blowpipe examina- tion of minerals. The colours of its beads, formed with various metallic oxides, are sometimes different to those pro- duced with borax, and it affords a ready means of detecting silica, which is solu- ble in borax but not in " micro." MILLERITE. [Sulphuret of Nickel. Haarkies.] Hex- agonal ; in six or twelve-sided capillary, acicular, or divergent filaments ; brittle ; opaque ; lustre metallic ; various shades of yellow ; often a grey or iridescent tar- nish ; streak like colour; H. 3-3 '5; G. 5-2-5-3. B., etc. In matrass gives off SO 2 and a yellow sublimate ; on C fuses, boils, forms a black magnetic mass ; with borax gives Ni reactions ; insoluble in HC1 ; soluble in warm HNO 3 ; more readily in Aqua Regia, forming a green solution. Comp Anhydrous sulphide of nickel. With nickel 64 '86 and sulphur 3514, the formula may be written NiS. No analysis of a British specimen is known to the author. Loc. Huel Sparnon, in capillary and divergent fibres of a dull yellow colour; Pengelley Mine, St. Ewe; Huel Chance; Fowey Consols ; Combemartin, and near Ilfracombe, in minute filaments lining cavities, and dispersed among crystals of galena. Found also in Wales, Scotland, Ireland, Germany, &c., but everywhere a rare mineral. MIMETITE. [Arseniate of Lead. Mimetesite. Kam- pylite.] Hexagonal, in regular six-sided prisms, often terminally modified (Figs. 188 and 190), or with curved faces ; also fibrous ; mammillary ; sectile or brittle ; imperfectly conchoidal or uneven ; trans- lucent, resinous, or pearly ; yellowish, greenish, often a brown tarnish ; streak white, or nearly so; H 3 '5-4; G. 7 '0-7 '3. Var. a. Kampylite, or Camphyllite, is a yellowish-brown variety, which occurs in crystals with convex faces (barrel- shaped). b. Hedyphane is a white variety. H. , etc. In matrass gives a white sub- limate ; on C fuses readily ; forms a white incrustation, yields an arsenical odour, and finally a bead of Pb with R flame ; more readily on addition of soda ; decomposed by strong HNOs, and by KHO. Comp. Anhydrous arseniate of lead, with some chloride of lead. The follow- ing analysis of a specimen from Huel Unity was made by Mr. Gregor, in 1809:- Arsenic anhydride 26 '40 Oxide of lead 69'76 Chlorine T58 Total 97-74 An analysis of a Cornish specimen by Dufrenoy was equal to 84 '55 per cent, of arseniate, 4 "5 per cent, of phosphate, and 9'05 of chloride of lead. With arseniate of lead = 90-66 and chloride of lead 9 '34, the formula might be PbCl 2 + 3Pb 3 As 2 or SAsgO^Pbo's + PbClg. With arsenic an- hydride 23-2, oxide of lead 67 '5, and chloride of lead 9 '3 the formula might be As 3 3 Pbo" 4 ( Pb"). 70 MINERAL. MOLYBDENITE. Lor,. Huel Unity, formerly, in very fine thick light brown translucent crys- tals, on galena, some more than three- quarters of an inch long, also acicular ; Huel Alfred, in the year 1824 fine crys- tals of Mimetite were here first disco- vered, in a cross lode ; "the crystals are splendant, of a rich topaz colour;" "some of the crystals of an inch in length, and J of an inch in diameter " 'Man. of Min., Truro, 1825); Huel Gorland, fine yellow crystals, on quartz ; Huel Rose and Huel Penrose, Sithney ; Huel Pros- per ; Penberthy Croft ; Huel Boys, En- dellion ; North Downs Mine ; Beeral- stone, with other ores of lead. Found also in Cumberland, Durham, Yorkshire, and most lead mining districts. O6. It usually has part of its arsenic anhydride replaced by phosphoric anhy- dride. Mineral. Any natural, homogenous, inorganic body. The word is used in this sense throughout this Handbook. Rocks are often composed of mixtures of minerals, more or less impure. Ex. Granite, The science which treats of minerals may be conveniently sub-di- vided into a. DETERMINATIVE MINERALOGY, in- cluding the chemistry of minerals. b. DESCRIPTIVE MINERALOGY, includ- ing the sub-science of crystallo- graphy. c. SYSTEMATIC MINERALOGY, or the ar- rangement of minerals into classes and systems. d. DISTRIBUTIVE MINERALOGY, or their geographical distribution. e. PARAGENETIC MINERALOGY, or their mutual association in lodes and rocks. Mineral Pitch. See Bitumen. MISPICKEL. [Arsenical Iron. Arsenical Iron Py- rites.] Rhombic ; in prisms or pyramids (Figs. 90 to 93, &c. ) ; often striated, curved, rough, or macled ; also acicular, or mas- sive, columnar, radiated, fibrous; or dis- seminated ; brittle ; fracture uneven ; opaque ; lustre metallic, often glimmer- ing only; tin- white to steel-grey; streak blackish-grey ; H. 5*5-6; G. 6-6 .B., etc. In matrass a red sublimate; on C fuses to a dark magnetic globule, giving a yellow incrustation, and a sul- phureous and arsenical odour ; soluble, except the sulphur, in strong HNO^, more readily in Aqua Regia. Comp. Anhydrous sulpharsenide of iron. With iron = 34 '37 per cent., sul- phur 19 '64, and arsenic 45 '99 the for- mulas FeS 2 + FeAs 2 , FeSAs or Fe 2 S 2 As a may be used. Loc. Botallack, Huel Castle, Levant, and other St. Just mines ; Penzance hill ; Wherry Mine ; Huel Mary and Provi- dence, Lelant (containing silver); St. Ives Consols ; West Poldice ; New Rosewarne ; Huel Herland, Huel Unity, Relistian, in chlorite, and other mines in Gwiuear ; Huel Vor, Breage ; Carn Camborne, Dolcoath, Cook's Kitchen, Tincrof t, Carn Brea, East Pool, and other mines in Camborne and Illogan ; Huel Tolgus ; South Tolgus ; the United Mines ; Huel Jewell ; Great He was United ; Huel Maudlin ; Holmbush ; Devon Great Consols ; Virtuous Lady (fine crystals, imbedded in chlorite); Tamar Mines, near Beerferris (fine crystals); Ivy Tor Mine, near Okehampton ; and many other localities in the two counties. It is a very common mineral in many mining districts in Cumberland, Scotland, and abroad. O6s. A large quantity of the white arsenic of commerce is obtained from this mineral, which is largely associated with the tin and copper ores throughout the district. A great deal of arsenic is, however, in some mines obtained from Leucopyrite. A nrjles. M M = 111 22' r r' = 33 32' MO 90 00 e e 120 48 11' 100 38 si 159 50 s s' 62 08 Mock Lead. An old name for Blende. Modified. Crystals which have small planes in place of their solid angles or edges are said to be modified ; thus Fig. 8 is an octahedron, modified by planes of the cube ; Fig. 9 a cube, modified by planes of the octahedron, &c. MOLYBDENITE. [Sulphuret of Molybdena. Molybdena Glance.] Hexagonal; in small crystals like Fig. 223, in irregular flat tables with perfect basal cleavage ; foliated, mas- sive, or scaly ; flexible, but not elastic ; opaque ; lustre metallic ; colour like freshly-cut lead ; streak greenish-grey ; marks paper like plumbago ; unctuous ; H. 1-1*5; G. 4-4-4-8. -B., etc. In matrass unchanged ; on C infusible, but gives off SO^ and burns away, colouring the flame green, except a small ash, which gives Mn or Fe reac- tions with soda and borax; effervesces when fused with soda ; insoluble in warm HC1 or HNO 3 ; soluble in strong H 2 SO 4 , forming a blue solution. Comp. Anhydrous sulphuret of mo- lybdenum. Pure specimens yield 59 '13 MUNDIC. NICCOLITE. 71 per cent, of molybdenum and 40 '87 per cent, of sulphur, the formula being MoS 2 . Loc. Huel Mary, Lelant ; Huel Friend- ship ; Huel Unity, and other mines in Gwinear ; Huel Gorland, and other parts of Gwennap, in elvan ; Menabilly ; Drake walls Mine, Calstock. It is also found in Cumberland, Scotland, and many foreign localities. It has been found in slags from copper smelting works. Obs. It may be distinguished from graphite by its superior sp. gr., blowpipe reactions, and the colour of its streak on porcelain. Mountain Cork, Mountain Paper, Mountain Leather, Mountain "Wood. See Amphibole. Mundic. See Pyrites. Murchisonite. See Orthoclase. Muriate of Copper. See Atacamite. Muriate of Silver. See Kerargyrite. MUSCOVITE. [Mica. Potash Mica.] Oblique (?); or Hexagonal (?); sometimes occurs in prisms, but more usually in tables like Figs. 239 to 241, or irregularly-shaped scales, or massive ; cleavage perfect and easily obtained, basal ; thin plates flex- ible and elastic ; tough ; lustre pearly or sub-metallic ; white, grey, brown, yellow, &c. ; often dichroic ; translucent ; thin plates transparent; streak white or grey- ish ; H. 2-3; G. 2-8-31. /?., etc. In matrass unchanged, but usually yields traces of HF ; on C some varieties are readily fusible to an opaque or glassy enamel : insoluble in HC1 or H 2 S0 4 . Comp. A complex silicate of alumina, iron, potash, &c. Loc. St. Dennis, near St. Austell. Probably most of the mica of the Cornish and Devonshire granites belongs to this species, but as crystals are rare it will probably be necessary in any future close examination of these micas to distinguish them by their optical properties. The chemical constitution of the micas seems too varied to form the basis of a sub- division, as least at present. Art files. M M' = 120 46' o b = 90 00' MO 98 40 or 107 05 Mb 119 38 bx 148 30 That there is still some confusion as to the species, is seen in the fact that, al- though the above angles are given as those of muscovite, Descloiseaux states that its crystals are right rhombic prisms of 120, or just the same as Lepidolite and Lepidomelane. N. Nacrite. See Gilbertite. Nail-headed Copper Ore. See Chal- cocite. Native Arsenic and other metals. See the metals. Native Loadstone, Native Magnet. See Magnetite. NATROLITE. [Needle Stone. Mesotype. Zeolith.] Rhombic, in slender or acicular prisms, like Figs. 112 and 113, with perfect lon- gitudinal cleavages; also mammilated, massive ; fibrous or radiating ; brittle ; fracture conch oidal or uneven; trans- parent or translucent, occasionally opaque ; lustre vitreous or silky, pearly on cleavage planes; white, yellowish, greyish, greenish, or brown ; streak white ; H. 5-5' 5; G. 2 '2-2 '3. B., etc. In matrass gives off water; on C fuses readily, often boiling ; colours the tip of the flame yellow ; the white residue treated with Co turns blue ; de- composed readily by HC1 or oxalic acid, depositing gelatinous silica. Comp. Hydrated silicate of soda and alumina. The Cornish specimens are not known to have been analysed, but foreign specimens yield about 48 '6 per cent, of silica, 277 per cent, of alumina, 16 '6 per cent, of soda, and 9 '7 per cent, of water. With these proportions the formula may be written Na 2 Si+Al 2 2Si + 2H 2 or Si 3 O 2 Al 2 o vi Nao 2 + 20H 2 . Loc. The rocks between Botallack and Huel Cock, and at Huel Carne, with Prehnite and Stilbite. Said to have been found also at Stenna Gwynn. It is also found in Ireland, Scotland, and many volcanic districts abroad. Obs. It is one of the very rarest British minerals. Angles. M M' = 91 00' 00 = 143 20> MO 116 40 Needle Spar. See Aragonite. Nephrite is said to have been found in the Lizard district, but the specimens were probably Saussurite. NICCOLITE. [Kupfernickel. Copper Nickel. Arse- nical Nickel. ] Hexagonal ; usually mas- sive and compact ; also reticulated, ar- borescent, reniform, or columnar ; brit- tle ; fracture uneven ; opaque ; lustre metallic ; pale copper red, often with a greyish or blackish tarnish ; streak pale brownish -black ; H. 5-5 '5 ; G. 6 '6-7 '3. 72 NICKEL OCHEE. OLIYENITE. B., etc. In matrass gives a faint white sublimate ; in open tube turns yellowish- green, and yields a white crystalline sublimate ; on C fuses easily to a glo- bule, giving off strong arsenical odours ; with borax yields reactions for Fe, Co, Ni, &c. ; soluble in Aqua Kegia, forming a green solution. Comp. Anhydrous arsenide of nickel. "With arsenic = 55 '98 per cent, and nic- kel 44 '02 the formula might be written NiAs. Loc. Huel Chance, St. Austell, with Millerite ; Fowey Consols, formerly, in the 200 fathom level; Pengelly Mine, St. Ewe, massive, and in tine fibres ; Black Down, Devon, with Rhodonite and Psilomelane. Found also in Scotland, Germany, France, and many other foreign localities. Obs. It may be easily distinguished from native copper, which it often some- what resembles in colour, by its hard- ness and brittleness. Nickel Ochre. See Annabergite. Noble Metals. Those metals the oxides of which can be reduced by heat alone, without the use of carbon or fluxes. Ex. Gold, Silver, Mercury, Pla- tinum. Nodular. Occurring in nodules. Nodule. An irregular rounded mass. O. Oblique Prismatic Arseniate of Copper. See Clinoclase. Ochre. See Hematite and Limonite. Octahedral Arseniate of Copper. See Lirocouite. Octahedral Cobalt Pyrites. See Smal- tite. Octahedral Copper Ore. See Cuprite. Octahedral Copper Pyrites. See Eru- bescite. Octahedral Iron Ore. See Magnetite. Octahedron. A solid figure having eight sides. In the regular octahedron these are equal equilateral triangles (Fig. 1). Odour. A character of some value in the discrimination of minerals in a few instances. Thus, many substances con- taining alumina give off a peculiar " earthy " smell when breathed upon or broken. Many ores containing sulphur or arsenic give off peculiar odours when broken or rubbed, aa is also the case with some varieties of quartz, calcite, barytes, &c. OLIVENITE. [Olive Copper Ore. Olive Malachite. Right Prismatic Arseniate of Copper. Pharmacochalcit.] Rhombic ; in prisms variously modified (Figs. 136, 137, 138); the planes often curved, striated, or rough ; more usually reniform, stalac- titic, fibrous, or capillary ; or massive, | nodular, granular, or earthy ; brittle ; I fracture conchoidal or uneven ; lustre I adamantine, vitreous, resinous, or silky ; shining to glimmering ; various shades of greyish or brownish-green ; streak like the colour, but lighter ; H. 3 ; G. | 3-9-4. Var. Wood arseniate is a fibrous con- I centric variety, with but little lustre, 1 and often almost ash-coloured. B., etc. In matrass gives off water and turns darker ; on C fuses at 1 to a i dark globule, which crystallizes on cool- | ing ; sometimes deflagrates ; deposits an abundant white inci'ustation on the cool part of the charcoal support ; gives off a strong arsenical odour ; with soda yields a malleable bead of copper ; solu- ble in HNO 3 , and partially so in ammo- nia, forming a blue solution. Comp. Hydrated arseniate of copper. The following are analyses of Cornish specimens, a. by Yon Kobell, a massive specimen ; b. and c. by Richardson, massive and acicular ; d. by Damour, sp. gr. 4 '378; e. by Hermann, sp. gr. 4135 : a. b. c. d. e. Arsenic anhy- dride 36-71 39-9 39-80 34 "87 33 "50 Oxide copper 56 '43 56 "2 56 '65 56 "86 56 '38 Phosphoric anhydride.. 3 -36 3 '43 5 "96 Water 3'50 3'9 3'55 372 416 Total 100 -00 100 -0 100 "00 98 '88 100 "00 The following analyses perhaps point to a different composition ; f . , a fibrous spe- cimen, by Hermann, G. 3 '913; g., by Thomson, fibrous ; h., by Klaproth: f. g. h- Arsenic anhydride... 40 '50 40 '61 45 "00 Oxide of copper 51 '03 54 '98 50 '62 Phosphoric anhydride I'OO Oxide of iron 3'64 Water .. . 3 '83 4 '41 3 "50 Total lOO'OO 100-00 9912 With arsenic anhydride 40'6 per cent., oxide of copper 56 "3 per cent., and water 31 per cent, the formula maybe written 4Cu, As 2 , H 2 or Cu 3 As 2 O 8 + CuH 2 O 2 or As 2 O 2 Cuo" 3 + CuHo 2 . Loc. Huel Unity, Huel Gorland, Ting Tang, Carharrack, and other mines in Gwennap (most varieties); Huel Buller; OPAL. OPTICAL CHARACTERS. 73 Pednandrea ; Tincrof t ; Beam Mine ; Phoenix ; Gunnislake ; Bedford United Mines, near Tavistock, in olive-green prismatic crystals, also fibrous and acicu- lar. It is found also in Cumberland, and many foreign localities. Obs. It will be seen that, as is fre- quently the case with arseniates, a small proportion of the arsenic anhydride is replaced with phosphoric anhydride. The massive varieties may be distin- guished from other arseniates of copper by their olive-green or ash-grey colour. Crystals may be known by their forms. Angles. M M' = 92 30' a b = 90 00' Mb 136 15 vb 125 46 Ma 133 45 ea 124 35 ee' 69 10 The combinations most frequently seen are Me, Meb, Meba, Mebav. The faces e and a are frequently uneven. OPAL. Amorphous ; massive, reniform, sta- lactitic, &c. ; brittle ; fracture conchoidal, even, or uneven; transparent to trans- lucent on edges ; lustre vitreous, resi- nous, or pearly ; colourless, milk-white, grey, red, brown, blue, green ; often a play of colours as the specimen is moved about ; streak white; H. 5 "5-6 '5; G. 1-9-2-3. Var. a. Common Opal is semi-trans- parent, and the colours are dull. b. Semi-opal is similar, but less trans- parent, and with still duller colours. c. Ferruginous Opal (Eisenkiesel or Iron-flint) is a hignly ferruginous variety. d. Wood-opal has the form and tex- ture of wood, of which it is often a silicified variety. e. Hyalite or Muller's Glass is vitre- ous, transparent, and colourless. f. Fire-opal is transparent or semi- transparent ; red or yellow, and irides- cent. g. Noble Opal is semi-transparent or translucent, of a milk-white, bluish, or yellowish-white colour, and exhibiting a beautiful play of colours. h. Cacholong is white and opaque. i. Hydrophane is nearly opaque when dry, but if immersed in water becomes nearly transparent. B., etc. In matrass usually yields water ; on C infusible ; sometimes de- crepitates, or turns red or opaque ; with soda melts with much effervescence to an opaque or transparent bead ; with micro, retains its form and appearance ; inso- luble in HC1, HNO 3 , H. 2 SO 4 , or Aqua Regia ; the powder soluble in KHO. Comp. Hydrated silica, with from 3'0 to 13 '0 per cent, of water, and varia- ble quantities of alumina, lime, magne- sia, potash, soda, or oxide of iron. LOG. 1. Common Opal. Botallack, Huel Stennack, Huel London, Trewel- lard, the Bunny, and Huel Spearn, St. Just ; Huel Spinster, Huel Damsel, and Huel Buller, near St. Day and Redruth; North Roskear, Camborne ; Huel Rose- warne, Gwinear ; Stenna Gwynn ; Huel Sovereign, massive, blue and white, pre- sented to Royal Institution of Cornwall in 1846 ; Trugoe ; Huel Maudlin ; Hay Tor ; on Dartmoor ; Lustleigh, &c. 2. Semi-opal occurs at most of the above localities, and especially near Oke- hampton, of a snow-white colour. 3. Wood-opal (silicified wood) occurs on the Blackdown-hills, Devon. 4. Ferruginous Opal occurs especially in the St. Just mines and near Cambome. 5. Fire Opal occurs, of a greyish-white colour, at Botallack; Rosewarne; Huel Spinster, and Huel Gorland (yellow), St. Day. 6. Cacholong, of a cream colour, on quartz and with steatite, from Botallack, is now in the Museum of tho Royal In- stitution of Cornwall. 065. Opal may be distinguished from the different varieties of calcedony by the larger quantity of water given off when heated in a matrass, by its inferior hardness and gravity, and by its solubi- lity in caustic potash. It is, however, possibly, only an extreme form of calce- dony, which usually contains some water, and is slightly soluble in caustic potash. The finest opals come from Mexico. Opalescent. Resembling opal in lustre and texture ; exhibiting a play of colours or iridescence, like fire-opal and noble opal. Opaque. Substances through which light cannot pass are said to be opaque. The minerals having true metallic lustre, as Pyrites, Galena, &c., are the most opaque. Ophiolite, Ophite. See Serpentine. Optical Characters of Minerals. The chief of these are : 1. Colour. 2. Lustre. 3. Diaphaneity. 4 , Phosphorescence. 5. Fluorescence. 6. Refractive power. 7. Polarization. Each of these are described under their respective heads. 74 OETHOCLASE. OKTHOCLASE. OR-THOCLASE. [Felspar. Potash Felspar. Orthose ; &c.] Oblique; in prisms, often flattened, or variously modified (see Figs. 172 to 180); two perfect cleavages (basal and clinodiagonal, M., O.), making angles of 90 00' ; brittle ; fracture conchoidal, un- even, or splintery ; transparent to nearly opaque ; vitreous to pearly ; white, grey, red, green, brown, or black ; streak white, greyish, or slightly tinted like the colour ; H. 6 ; G. 2 '5-2 '6. Far. a. Adularia is colourless and transparent ; sometimes a little green- ish, opalescent, or a faint play of colours ; cross fracture conchoidaL b. Moonstone is like Adularia, but contains bluish-white spots, which, when held to the light, appear pearly or silvery. c. Murchisonite is a flesh-red variety, pale or deep in tint ; viewed in an oblique direction it has gold, yellow, or silvery reflections on a third cleavage ; a micro- scopic examination seems to indicate that it is a compound of Orthoclase and Albite. d. Common Felspar. Colour very va- rious, but often pink or reddish, and usually a not very brilliant lustre. e. Erythrite. A flesh-red variety, con- taining 3 per cent, of magnesia. f. Amazon Stone is a clear green cleav- able variety. g. Sanadin, or Ryacolite, occurs in glassy transparent crystals, mostly tabu- lar. It is often associated with modern lavas or pumice. h. Compact Felspar is an uncleavable variety. i. Pitchstone is, perhaps, an amor- phous variety, of dark pitchy appearance. B., etc. In matrass not changed, or loses colour ; on C fuses at about 4 to a blistered slag, or infusible ; with borax dissolves slowly, with effervescence, to a clear glass ; insoluble in micro.; insoluble in HC1 and HNO> Comp. Anhydrous silicate of potash and alumina, with small quantities of other bases. Of the following analyses a. and b. are Orthoclase, from Trewavas Head, Breage, by Professor Haughton, recently (a. from veins at foot of cliff, b. from granite at head of cliff); c. and d. of Orthoclase from the "Glass Mine," Roche, by Phillips (Phil. Mag. Feb., 1871); e. is an analysis of felspar from Dartmoor ; f. of Murchisonite from Ex- minster, both by Prof. Church (Rep. Dev. Assoc., vol. II., p. 201); g. is Murchiso- nite, from Dawlish, by Phillips (Phil. Mag. vol. 1, 1814, p. 448). a b. c. d. Water 0'40 0'40 0'83 0'50 Silica 63-60 63'20 65'00 65'33 Alumina 21 '04 21 '00 19 '00 19 '16 Ferric oxide ... trace trace '50 *50 Lime 0'90 0'68 T57 1'68 Magnesia - trace trace Potash 9-91 10-30 10'37 10'37 Soda 3-08 2'75 2'40 2'40 Total 98-93 98 '33 99 '67 99 '94 e. f. g. Silica 65-61 65'27 68'60 Alumina 1973 20'34 16'60 Potash 1273 12'43 14'80 Soda 1-50 1-44 Lime 0'33 0'33 Magnesia 010 019 Total 100-00 100-00 lOO'OO With silica 69 '7 per cent., alumina 19 7 per cent., and potash 10 '6 the formula may be written 6Si, K 2 , A1 2 or Al 2 O 3 3Si O 2 +K 2 OSiO 2 + 2SiO 2 or Si 6 O 8 Ko 2 Al 2 o vi . This last is the formula given by Pro'fes- sor Frankland. With silica 60 "5, alumina 25 "7, and potash 13 '7, the formula might be 4Si, K 2 , A1 2 or Al 2 O 3 3SiO 2 + K 2 OSiO 2 or Si 4 O 4 Ko 2 Al 2 o Ti . Loc. 1. Adularia Tintagel and Dela- bole, in slate ; Kit-hill, Callington ; said to have been found also in prisms at St. Just. 2. Moonstone is said to have been found at Gluvias Burnt-house, near Penryn. 3. Murchisonite Heavitree, near Exe- ter; Exminster; Topsham ; Jacobstowe ; Crediton ; and near Dawlish, in the red conglomerate ; the finest masses are ob- tained on the coast between Teignmouth and Dawlish, often lying on the beach. 4. Common Felspar Fine crystals or masses have been obtained at the Scilly Isles ; Boscreagen Cove, near the Land's End, of a deep red colour ; Pendeen Cove, in fine crystals imbedded in schorl rock ; Botallack, Balleswidden, and many of the St. Just mines, in fine masses ; Mulvra-hill, Sancreed ; Morvah United Mines ; Ding Dong, Madron ; St. Ives Consols ; Huel Mary, and other mines in Lelant ; Lamorna Point, near Penzance ; the Marazion Mines ; Huel Darlington ; St. Michael's Mount ; Trewavas Head, Tremearne, and Great Huel Fortune, Breage, in granite ; Huel Ann, Trumpet Consols, and many other mines in Wen- dron ; Kynance ; near the Old Lizard Head, in green talc ; Coverack Cove, Huel Union, Towednack, and other places in the Lizard district ; the United ORTHODIAGONAL. PENTLANDITE. 75 Mines, Tresavean, Huel Fortune, and other mines in Gwennap ; East Huel Crofty; Dolcoath ; East Pool; Huel Coates, St. Agnes (in twin crystals, some converted intoCassiterite); Cligga Head, in a decomposing granite ; near Truro, in beautiful pink crystals, in several elvans ; St. Stephens, St. Austell Hill Mine, and other localities near St. Aus- tell ; Luxulyan ; and a large number of other localities near the granite. Birch Tor Mine ; North Bovey ; Hay Tor ; Ivybridge, in altered Devonian slate, with Chiastolite ; Bovey Tracey, in fine red crystals ; Lundy Island, with rock crystal ; and many other places. 5. Sanadin, or Glassy Felspar Little Haldon-hill, near Teignmouth, in large Ttals imbedded in porphry. Pitchstone Skewes, Crowan ; Carn Brea ; South Huel Basset. Obs. Only the more remarkable loca- lities of felspar are given above, or where it is obtained in very pure specimens. Felspar forms a large proportion of the widely-spread masses of granite in Corn- wall and Devon. The only certain way to distinguish between massive ortho- clase and albite is by analysis ; but good indications may be obtained by observing the cleavages, and also by the blowpipe behaviour. See Albite. Angles. T T = 118 54' O x = 129 41' TO 112 16 Oy 99 38 TM 120 36 Mn 134 57 Tn 95 14 Mz 150 35 Tx 110 40 Mo 116 53 Ty 134 19 oy 140 33 OM 90 00 oz 124 59 Orthodiagonal. That lateral axis which is at right angles to the principal in the eblique system ; also a plane parallel to that axis and the principal. Thus, in Figs. 168, 169, the plane a. is orthodia- gonal ; in 170, 171, the plane T. Oxide. A combination of an element with oxygen is so called. Those oxides which form acids by addition of water are also called anhydrides by many chemists. Oxide of Antimony. See Yalentinite and Senarmontite. Oxide of Arsenic. See Arsenolite. Oxide of Bismuth. See Bismite. Oxide of Cobalt. See Asbolane. Oxide of Copper. See Cuprite anc Melaoonite . Oxide of Iron. See Magnetite, Hema tite, Limonite, and Goethite. Oxide of Lead. See Plumbic Ochre. Oxide of Manganese. See Pyrolusite Manganite, Psilomelane, and Wad. Oxide of Tin. See Cassiterite. Oxide of Tungsten. See Wolframite. Oxide of Uranium. See Pitchblende and Zippaeite. Oxidising Flame. See Instructions for ihe Examination of Minerals before the blowpipe in Part I., and "Blowpipe Reactions," p. 18, Part II. Oxychloride of Copper. See Ataca- mite. Oxydulated Iron. See Magnetite. Oxygen Ratio. This is a terra, used to express the rates between the proportion if oxygen in base and acid in a compound containing both. The modern unitary ;heories of chemistry have, therefore, in some degree lessened the use of the ex- pression ; since, by these, salts are not .ooked upon as compounds of base and acid. The oxygen ratio is most referred ;o in speaking of silicates, and was formerly considered of great value in determining their specific value. Pro- fessor Dana, however, would seem to consider it of but little importance, as the following remarks shew: "The fel- spar group is remarkable for its unity in crystallographic and all physical charac- ters, evincing the profoundest isotypism, and yet the O ratio for the bases of silica varies from 1-1 to 1-3." (Syst. Min., 1868.) See also p%ge 46, Part II. of this Handbook, under Felspar. P. Parti-coloured. When the colour of a mineral specimen is different in different parts this term is often used. Peacock Copper. See Chalcopyrite. Peach. A Cornish name for Chlorite. Pearl Spar. See Dolomite. Pechurane. See Pitchblende. PENTLANDITE. [Eisennickelkies. Sulphuret of Iron and Nickel.] Cubical, with octahedral cleavage ; usually massive, granular, or imbedded ; brittle ; fracture uneven ; opaque ; lustre metallic ; light bronze yellow or brownish; streak dark brown ; H. 3'5-4; G. 4'6; not magnetic. B., etc. In matrass gives a yellow- sublimate ; in open tube a strong sul- phureous odour; on C fuses to a dark brittle bead; with borax and micro, yields iron reactions. Soluble in HNO 3 , forming a greenish-yellow solution. Corny. Anhydrous sulphide of iron and nickel. With iron 42 '0 per cent., sulphur 35 '9 per cent., and nickel 22 '1 per cent, (which is very near Scheerer's analysis of a Norwegian specimen), the formula may be written 2FeS + NiS. 76 PEEOXIDE OF IEON. PHOSPHATES. LOG. Huel Jane, near Truro, about the year 1857, in large masses, associated with Vivianite. 06?. Its general appearance, physical characters, and blowpipe reactions are not greatly different to those of Pyrrho- tite (Magnetic Pyrites). It is not, how- ever, magnetic like Pyrrhotite, and the considerable proportion of nickel may be easily detected by humid analysis. Peroxide of Iron. See Hematite, Limonite, Goethite. Peroxide of Tin. See Cassiterite. Petroleum. See Bitumen. PHARMA COSIDERITE. [Cube Ore. Arseniate of Iron.] Cubic; in cubes usually modified (Figs. 2, 3, 9, 16, 49, 50), with some planes striated, others curved, or rough ; rarelv massive ; brittle ; fracture uneven or sub-conchoi- dal ; translucent to opaque ; lustre vi- treous, adamantine, or greasy ; various shades of green, often tarnished yellow or brown ; streak pale green, yellowish, or brownish; H. 2 '5; G. 2 '9-3; pyro- electric. .B., etc. In matrass turns red, gives off H 2 O and a whitish sublimate ; on C fuses easily to a grey magnetic slag, yielding a very strong alliaceous odour ; with borax and micro, gives Fe reac- tions ; soluble in HC1 or HNO 3 . Comp. Hydrated arseniate of iron. The following are analyses of Cornish specimens of " arseniate of iron," a. and b. by Chenevix, c. and d. by Berzelius : a. b. c. d. Arsenic anhydride 31 '0 33 '0 38 '00 40 '20 Peroxide of iron ... 45 '5 27 '0 40 '56 39 '20 Oxide of copper... 9'0 22'5 0'60 0'65 Silica 4-0 3'0 0'35 176 Phosphoric anhy- dride - - 0-70 2-53 Water... .. 10 "5 12 "0 19 "57 18 '61 Total 100-0 97'5 9978 102'95 With arsenic anhydride 41 '7 per cent., peroxide of iron 38 '1 per cent. , and water 19 '6 per cent., the formula may be writ- ten 4Fe 2 , 3As 2 , 18H 2 or 3(Fe 2 As. 2 O 8 + 5H 2 O)+Fe 2 H 6 6 e or 3(As 2 O 2 Fe 2 o vi 5OH 2 ) + Fe 2 Ho 6 . These formulae agree* pretty well with the analyses c. and d. , but not with a. and b., which are, perhaps, seme other mineral. As is usual, a part of the arsenic is replaced by phosphorus. Loc. Formerly at Huel Jane, near Truro, in cubes, with the alternate angles replaced, some with all the angles and edges replaced ; Huel Falmouth ; Huel Unity, Huel Gorland, and Carhar- rack Mine Gwennap, with many ores of copper (some inferior specimens have lately been found on the burrows in this neighbourhood); Carn Brea Mine, in dark green or yellowish -green cubes ; Botal- lack, Levant, and Huel Owles, St. Just, in crystals which were usually covered with a dark tarnish ; Beam Mine, in rhombic dodecahedrons of a brilliant grass-green, bottle-green, or pale blue colour, the size of pins' heads (Man. of Min., Truro, 1825, p. 63); recently at Pednandrea, in fine green modified cubes. Obs. This mineral is rarely found other than crystallized, and the crystals are usually very small, one-eighth of an inch being considered a good size. A ngles a a = 90 00' dd 120 00 o o 109 28 ak 109 28 a d 135 00 ao = 125 od 144 ok 164 k k 152 dk 160 16' 44 12 44 32 The forms 2, 3, 9, 16, 49, 50, are all Cornish, most of them being in Mr. Greg's collection. Phosgenite. See Cromfordite. Phosphates. Compounds of phospho- ric anhydride with metallic oxides are so called, or phosphoric acid in which the hydrogen has been replaced by a metal. Phosphates may often be detected by the green tint which they impart to a blowpipe flame, and especially if first moistened with H 2 SO4 and heated in OF. In the presence of copper and some few other bases this reaction is obscured, when very small quantities may be de- tected by the following method : The material to be tested is finely powdered, mixed with five times its volume of a mixture of three parts carbonate of soda, one of silica, and one of nitre, and the whole fused on platinum foil. The fused mass is dissolved in water and filtered ; to the clear liquid a few drops of a solution of carbonate of ammonia is added. The solution is then boiled, and silica sepa- rates as silicate of soda, which should be filtered off. Acetic acid is then added to the clear solution, slightly in excess, it is then boiled to expel carbonic anhy- dride, and a drop of solution of nitrate of silver added. If a yellow precipitate should fall after this treatment it is evi- dence of phosphorus. Most arseniates contain at least traces of phosphoric anhydride. The phos- phates found in the two counties are the following : Apatite, Pyromorphite, Childrenite, Vivianite, Beraunite, Libcthenite, C/iurchite, Lunnite, Demidoffite, Torbernite, A utumte, Wavellite. PHOSPHATE OF CERIUM. PINITE. 77 Of these, Apatite and Pyromorphite are anhydrous ; the rest are hydrous. In many of them traces of arsenic anhy- dride may usually be detected. Phosphate of Cerium. See Churchite. Phosphate of Copper. See Libethe- nite, Lunnite, Demidoffite, and Torber- nite. Phosphate of Iron. See Vivianite, Beraunite, and Childrenite. Phosphate of Lead. See Pyromorphite. Phosphate of Lime. See Apatite. Phosphate of Uranium. See Autunite and Torbernite. Phosphorescence. When minerals ap- pear luminous under certain conditions they are said to be phosphorescent. This property may be produced by 1. Friction. Ex. Quartz (frictio-phos- phoric). 2. Heat. Ex. Fluor (pyro-phosphoric). 3. Electricity. Ex. Apatite (electro- phosphoric). 4. Exposure to sunlight. Ex. Dia- mond, Calcite (helio-phosphoric?). Phosphorite. See Apatite. Physical Characters of Minerals. A convenient sub-division of the characters of minerals is into 1. Physical. 2. Chemical. 3. Optical. The chief physical characters are 1. Form, 5. Hardness, 2. Cleavage, 6. Specific gravity, 3. Fracture, 7. Magnetism, 4. Frangibility, 8. Electricity. PIGOTITE. Amorphous ; incrusting ; brown ; streak and powder yellow. B. , etc. In matrass gives off water ; on C burns away slowly, leaving a small quantity of white ash, which, when treated with Co, turns blue ; insoluble in water or alcohol ; soluble in HC1 (?). Comp. A hydrated Mudesite of alu- mina, the formula of which is said to be 4A1 2 3 + C 12 H 5 8 +27H 2 . Loc. Some of the granite caves of the coast of Corn .vail. Obs. It can hardly be considered a mineral. It has been observed in places where the surface-water trickles down over the granite rocks. "The organic constituent of Pigotite is considered by James F. Johnston to be derived from the decay of the various plants which grow on the moist moorlands above, and which being carried by the waters into fissures in the granite beneath, combines with the alumina of the decomposed fel- spar, and when it reaches the air depo- sits itself over the roof and sides of the cavern in the form of layers, varying from two to three inches in thickness." (Bristow's Gloss. Min., p. 288.) PINITE. Khombic ; usually in six or twelve - sided prisms, sometimes with the termi- nal edges modified (Fig. Ill); sectile or brittle ; fracture uneven ; translucent to opaque ; dull, glimmering, or waxy ; re- sinous or pearly ; greyish, greenish, or dark brown ; streak white or grey : H. 2-3; G. 2-7-2-9. B., etc. In matrass gives off a little H 2 O ; on C loses colour, and fuses on thin edges to a blistered glass or enamel; with Co turns bluish ; with borax yields Fe reactions ; imperfectly decomposed by HC1. Comp. No analysis of a British spe- cimen is known to the author, but foreign specimens contain from 47 "0 to 56 "0 per cent, of silica, 25 "0 to 29 '0 per cent, of alumina, 7'0 to 8'0 per cent, of protoxide of iron, 6'0 to 10 "0 per cent, of potash, and 2'0 to 8'0 per cent, of water. This composition differs scarcely at all from that of some Agalmatolites, with the ex- ception of the iron. Loc. Trewellard Cliff, St. Just ; the high hills south of Trewellard, in granite (Trans. Roy. Geol. Soc. Corn., J. Carne, vol. ii); Nangisel Cove, Sennen; Mulvra- hill, near Sancreed ; in the rocks to the east of Lamorna Cove, in small dark brown crystals, like Fig. Ill ; Tol Pedn Penwith; St. Michael's Mount; in im- bedded crystals in an elvan running through St. Hilary and Breage, by Tre- goning-hill, and in another running from Tregurtha to Praa Sands ; these elvans are largely used for road material, and good specimens may sometimes be ob- tained in the heaps by the roadside ; be- tween St. Austell and Grampound, in an elvan running from Polgooth, by Trewi- then, to Court Mill ; found also in Scot- land, and many foreign localities. O65. Dana includes Finite with Agal- matolite and many other minerals in a group of hydrous alkaline silicates, re- lated chemically and physically to ser- pentine. He observes that it occurs in pseudomorphous crystals after lolite, Neph elite, Scapolite, Felspar, and Spodu- mene. Some of the Breage specimens have a bluish colour, and considerable lustre. Angles. MM' = 119 10' ab = 90 00' MO 90 00 ad 150 25 Ma 120 25 dd' 120 50 Or 132 12 78 PITCHBLENDE. POLYBASITE. Sometimes a face r is observed in the crystals from Lamorna, which truncates the angle M O. PITCHBLENDE. [Uranium. Pechurane.] Cubic (?) or amorphous ; botryoidal, reniform, mas- sive, or disseminated ; columnar, curved, lamellar, or granular ; brittle ; fracture uneven or small conchoidal ; opaque ; lustre metallic, sub-metallic, or dull ; greyish, greenish, or brownish-black ; H. 5'5; G. 6-4-7. B., etc. In matrass no change ; on C infusible ; with borax gives a yellow bead in OF ; greenish in RF ; with micro, gives U reactions ; insoluble in HC1 ; soluble in warm Aqua Regia, or hot HNO 3 , forming a yellow solution. Oomp. Proto-peroxide of uranium. No analysis of a British specimen is known to the author. With uranium 8478 and oxygen 15 '22 the formula would be TJ + Ua or U 3 O 4 . Loc. Huel Edward, St. Just (many years ago and again recently) ; Botallack, formerly ; Huel Trenwith ; Huel Provi- dence ; Wherry Mine ; Tincroft, with autunite ; Huel Basset ; Huel Buller ; Tolcarne; Ting Tang; Pednandrea(mam- millary); Roskrow United, Ponsanooth ; St. Austell Consols; Treemoor, Withiel; found also in Norway, Sweden, Ger- many, and many other foreign localities. 06s. It may be distinguished from blende by its sp. gr. and fracture ; from wolfram by its fracture and streak. It is used for enamel painting, colouring glass for optical purposes, &c. It is often associated with ores of silver, lead, and copper. Pitch Ore. See Pitchblende. PITTICITE. [Pitchy Iron Ore.] Amorphous ; reni- form, stalactitic, or massive ; brittle ; fracture flat conchoidal or earthy ; trans- lucent on edges to opaque ; lustre vitre- ous, resinous, or dull ; yellow, reddish, or blackish-brown ; streak pale yellow ; H. 2-3; G. 2-3-2-4. B., etc. In matrass gives off H 2 O and yields a white sublimate, often crystal- line ; on C melts readily to a dark mag- netic globule, giving off copious white fumes with an alliaceous odour, and de- positing a white coating on the cool part of the charcoal support ; soluble in warm HC1 or HNO 3 . Comp. Hydrated arseniate of iron, of very variable and uncertain composition. Loc. Dolcoath, formerly ; specimens were found in the year 1866, by Dr. C Le Neve Foster, which were at first soft and plastic, but soon became harder, and fell to pieces ; these are of a greyish- yellow colour. Found also in France, Germany, and many other localities. 06s. It is probably a product of the decomposition of mispickel, with which some parts of Dolcoath abound. Plastic. Capable of being moulded like clay. Plumbago. See Graphite. PLUMBIC OCHRE. [Earthy Lead Ore.] Amorphous; mas- sive ; compact or earthy ; opaque ; dull ; yellow, brownish, or bluish -brown ; streak the same; H. 0-2; G. 8U B. , etc. In matrass unchanged ; on C easily reduced to a malleable bead of lead ; soluble in HNO 3 without efferves- cence. Comp. Anhydrous oxide of lead. Loc. " Earthy Lead Ore " was found about the year 1820 in Huel Mexico, Perranzabuloe ; it was " amorphoxis, or in minute six-sided prisms (Plattnerite?) in cavities in ferruginous quartz;" the colour was straw-yellow or greenish- yellow. A specimen analysed by Mr. Michell yielded 20 '2 per cent, of lead, 24 '6 per cent, of iron, 2 '4 per cent, of silver, 37 "0 per cent, of silica, and 14 '0 per cent, of oxygen, with a trace of chlorine. Plush Copper. See Cuprite (Chalco- trichite). Podar. An old Cornish term for py- ritous dust or waste. POLYBASITE. Hexagonal (Nicol) or Rhombic (Dana); usually in short tabular prisms, the bases striated parallel to the alternate edges ; also massive or disseminated ; fracture uneven ; opaque, or translucent in very thin pieces ; lustre metallic ; iron-black ; thin plates cherry red by transmitted light; streak iron-black; H. 2-2 '5; G. 6-0-6-25. B., etc. In matrass decrepitates and fuses ; in tbe open tube yields a sul- phureous odour and a yellow or reddish sublimate ; on C deposits a white coating of the oxides of Sb As or. Zn, fusing, boiling, and yielding finally a white me- tallic alloy ; with micro, gives indications of Cu ; by cupellation a bead of silver ; decomposed by HNO 3 . Comp. Anhydrous sulph-antimonide of silver and other bases. A Cornish specimen yielded to Joy the following results : POLYTELITE. PSETJDOMOEPH. 79 Sulphur 15*87 Antimony 5"46 Arsenic 3'41 Silver 72'01 Copper 3'36 Iron ... 0-34 Total 100-45 Loc. "Cornwall" is given as a loca- lity of Polybasite by Dana, but this may refer to a Cornwall county in the United States. Polytelite. See Fahlerz. Porcelain Clay. See Kaolin. Porcelain Jasper. A highly indurated clay, much resembling true Jasper, but containing a large proportion of alumina. PORCELLANITE. [Porcelain Spar.] Rhombic (Brooke), prismatic angle 88, or tetragonal (Dana), two cleavages forming right angles ; also massive, compact, or columnar ; brittle ; fracture uneven: transparent to opaque; lustre vitreous, pearly, or greasy ; white, grey, greenish, bluish, reddish ; H. 5-5-6; G. 2-6-2-74. B., etc. In matrass yields a little water ; on C loses colour, and fuses at from 3 to 4 to a blebby glass ; treated with Co turns blue ; imperfectly decom- posed by HC1. Comp. Silicate of alumina, lime, and soda, with perhaps silica 50'6 per cent., alumina 28 '1 per cent., lime 15 '6 per cent., soda 5 '7 per cent. Loc. It is said to have been found near Redruth(?). It occurs in Norway, Sweden, and many foreign localities. Obs. It is readily decomposed by ex- posure to air and moisture, and con- verted into friable porcelain earth, which frequently retains the form of the crystals. Potash Mica. See Muscovite. Potato Stone. See Geode. Porphyry. Any rock which contains disseminated crystals distinct from the main mass. Thus there may be fel- spathic porphyry, claystone porphyry, granitic porphyry, &c. The _ Cornish elvans are usually porphyritic. The term was originally applied to a reddish or purplish syenitic porphyry found in Upper Egypt. Porphyritic. See Porphyry. Potstone. See Steatite. PREHNITE. Rhombic ; in prisms (Fig. 96), striated, or closely aggregated laterally ; cleavage basal, perfect ; often botryoidal, reni- form, or radiated ; brittle ; fracture un- even ; translucent to transparent ; lustre vitreous or pearly; white, or various shades of pale green or yellow; streak white; H. 6-7; G. 2 '9-3; pyro-electric. B. , etc. In matrass gives off H 2 O ; on C fuses at about 3 to a blistered glass, with effervescence ; scarcely acted upon by acids until after ignition, when HC1 completely decomposes it, gelatinous silica being deposited. Comp. Hydrated silicate of alumina and lime. With silica 43 '0 per cent., alumina 24 '4 per cent., lime 28 '4 per cent., and water 4 "2 per cent., which is pretty nearly what is yielded by Scottish specimens, the formula may be written A1 2 , 3Ca, 3 Loc. Roscommon cliff ; a vein in the cliffs between Botallack and Huel Cock, with stilbite and mesotype ; Botallack, Huel Cock, Levant, all in St. Just, formerly, in pale green groups of crys- tals ; fine specimens are found in Scot- land, Ireland, and many foreign locali- ties. Angles. MM 100 00' if 92 00' Me 128 33 Mi 91 30 ij 177 20 Prism. A solid figure, the base of which is any right-lined figure, while the sides are parallel. Figs. 2, 110, 111, 171, &c., are prisms. In mineralogy very short prisms are called tables, and the crystals are said to be tabular. Prismatic Arseniate of Copper. See Olivenite. Prismatic Arsenical Pyrites. See Mis- pickel. Prismatic Bismuth Glance. See Bis- muthinite. Prismatic Cobalt Mica. See Erythrite. Prismatic Copper Mica. See Chalco- phyllite. Prismatic Iron Pyrites. See Marca- site. Prismatic System. See Crystallogra- phy : Rhombic System. Prismatic Talc Mica. See Chlorite. Prismatoidal Manganese Ore. See Manganite. Protoxide of Uranium. See Pitch- blende. Pseudomorph. A substance having the form of one mineral and the compo- sition of another. The chief kinds are those which are 1. Pseudomorphs by loss of an ingre- dient, as when LiMONiTE is found in the form of CHALYBITE. Such specimens have been found in several mines at St. Just, and other places in the two coun- ties. 80 PSEUDOMOBPH. PSEUDOMOBPH. 2. Pseudomorphs by gain of an ingre- dient, as when LiMONiTE occurs in the form of HEMATITE. This is no uncom- mon condition of Limonite in many iron mines. 3. Pseudomorphs by exchange of in- gredients, as when GALENA occurs in the form of PYKOMORPHITE. Very fine exam- ples of this change occurred at Huel Hope, in the year 1827. In some specimens of Limonite after Pyrites ; and in those of Felspar after Chlorite, observable in the granite of the north and western flanks of Carn Marth, the change often appears to commence in the centre and to proceed outwards. Sometimes this change proceeds until the whole of the original substance is replaced by one of totally different composition, as when Quartz, Calcedony, or Horn- stone appear in the form of Fluor. Thus, Mr. J. Carne states that in some cubic Quartz found at Botallack is a crystal "in which the acuminated angles often seen in Fluor are well preserved. 1 ' (Trans. Eoy. Geol. Soc. Corn., vol. II.) 4. Pseudomorphs of dimorphous sub- stances, as when CALCITE is found in the form of AKAGONITE. 5. Pseudomorphs by incrustation, formed as moulds on the surface of other minerals. These are often hollow, and sometimes contain fluids. In some speci- mens of Calcedony in hexagonal tabular crystals from Balleswidden, in one "the calcedony is merely a deposit on Calcite, which is everywhere visible ; in the other, where the Calcite is seen at all, the line of it is but just perceptible, and in some parts is wholly gone, and the solid crystal of Calcedony remains. " 6. Pseudomorphs by infiltration, formed as casts within the moulds men- tioned in 5. 7. Pseudomorphs after organic forms, as when the substance of a fossil is re- placed with mineral matter. With these, the arborescent forms often met with in native copper and native silver must not be con- founded. Such forms are in no way connected with organization, they are simple dendritic accretions, analagous to those of water on a window pane on a f rosty'night. Of this kind were, probably, some specimens of metallic copper, in the form of plants, from Treskerby, *' The stem, and often the fibres of the leaves, were very perfect," so that "a good botanist might almost venture to give the names and descriptions of the plants." (J. Carne, Trans. Roy. Geol. Soc. Corn., voL II.) The following is as/ complete a list of Devonshire and Cornish Pseudomorphs as the author has been able to obtain. Where it was possible, he has indicated the class in which the specimen should be placed, but in some instances no par- ticulars were obtainable : Group 1. Pseudomorphs by loss of ingredients In the form of Locality. 1 Limonite, Chalybile, St. Just. 2 ,, ,, Perran Iron Lode 3 Garnet, Belstone Consols. AUTHORITIES. 1, J. Carne (Trans. Roy. Geol. Soc. Corn., vol. vi.); 2, Prof. Smyth (ibid. vol. vii., p. 336); 3, J. Davis, Brit. Mus. (private information). Group 2. Pseudomorphs by gain of ingredients In the form of Locality. 1 Limonite, Hematite(?)Reatormel. (?) This locality is doubtful. The author has seen a well-marked specimen which is said to have come from there. Group 3. Pseudomorphs by gradual exchange of ingredients In the form of Locality. 1 Limonite, Pyrites, Levant. Huel Owles. Trecrobbeu Mine Carnmarth. Huel Ruby. Restormel. Huel Maudlin. 4 Oxide of Iron,Felspar, 5 Hematite, Calcite, 6 Goeihite, Pyrites, 7 Wolfram, Scheelite, 8 Galena, Pyromorph.JlueUlope. 9 Chalcopyrite, Chalcocite, St. Ives Consols. 10 Cerussite, Galena, 11 Cassiterite, 12 13 14 15 Chlorite, 16 17 18 19 Calcedony, 20 21 22 Kao n, 23 24 25 26 27 28 ScAorZ, AUTHORITIES. 1, 10, 14, 19, 20, J. Carne (Trans. R. G. S. C., vol. vi.); 2, 6, 13, 16, 28, R. Pearce (Rep. Roy. Inst. Corn., 1861, 1863, and private information); 5, Prof. Smyth (private information); 18, 26, Prof. Church (ditto); 7, Greg and Lettsom, (p. 354); 8, Michell (Man. Min., Truro, 1825, p. 9); 11, W. M. Tweedy (Rep. Roy. Inst. Corn., 1841, p. 39); 12, T. M. Hall (Min. Direct., p. 131); 3, 4, 9, 15, 17, 22, 23, 24, 25, 27, the author has himself seen, recently, many in situ. Group 4. Pseudomorphs of dimor- phous substances. No example from Devon or Cornwall known to the author. Felspar, Huel Coates. n Carn Brecon. Balleswidden. Quartt, Huel Primrose. Felspar, Carnmarth. United Mines. Pennance. Carclaze. Calcite, Balleswidden. Datholite Haytor. North Roskear. Felspar, Balleswidden. }} Tregoning hill. if Tremearne. Vogue. | " Carclaze. St. Stephens. Felspar, St. Enoder. PSEUDOMORPH. PSEUDOMORPH. 81 Group 5. Pseudomorphs by incrusta- 9 Quartz, Fluor, Huel Sparnon. ttow, 10 ,, ,, BeerftTris. 11 South Hooe. In the form of Locality. 12 Beeralstone. 1 Quartz, Fluor, Huel Spearn. 13 ", Calcite, Gwennap. 2 ,, Botallack. 14 St. Ives Consols. 3 Caruidjack. 15 ,, ,, Botallack. 4 Huel Alfred. 16 Hay Tor. 6 Huel Herland. 17 ,, Dolomite, Levant. 6 , United Mines. 18 Huel Cock. 7 , Consolidated Ms. 8 , ,, Trevaseus. 9 , North Roskear. 19 ,, Felspar, Boscagel Downs. 20 Calcedony, Calcite, North Roskear. 21 ,, ,, Near Penzance. 10 , North Pool. 22 Hay Tor. 11 , Dolcoath. 23 ',', Dolomite, North Roskear. 12 , Huel Trelawny. 24 ,, Levant. 13 , Huel Mary Ann. 14 ,, ,, Near Holrnbush. 15 Chalybite Botallack. 25 ,, Barytes, Herodsfoot. 26 ,, ,, Huel Mary. 27 Limonite, Calcite, S. Huel Basset. 16 ,, Dolcoath. 17 ,, ,, Cook's Kitchen. 28 ,, Pyrites, Hennock. 9(\ Bottilhick 18 Calcedom}, Fluor, Craft-an-verth. 30 " S. Huel Basset. 19 Galcite, Balleswidden. 20 Chalybite, SelenitQ, Virtuous Lady. 31 Chalybite, Huel Owles. 32 ,, D ilomite, 21 ,, ,, Beeralstone. 22 Huel Friendship. 23 Fluor, Virtuous Lady, 24 Galcite, Beeralstone. 33 Goethite, Pyrites Restormel. 34 Pyrites, Chalybite, Restormel. 35 ,, Calcite, Huel Mary. 36 ,, Tavistock. 25 Pyrites, Herodsfoot. 26 Quartz, Chalybite, Cousol. Mines* 37 " Albite, Consolidated Ms. 38 ,, Barytes, Herodsfoot. AUTHORITIES. 1, 2, 4, 9, 18, 19, J. Came 39 Marcasite, Calcite^ Tamar Mine. (Trans. R. G. S. G., vol. vi.); 3, 15 (ibid. vol. 40 Chalybite, Calcite, Beeralstone. ii.); 5, 6, 8, 10, 11, J. Garby (ibid. vol. vii., p. 73); 12, 13, 16, 17, R. Pearce (private informa- tion); 14, 25, Prof. Smyth (ditto); 20, 22, 23, 24, Greg and Lettsom (p. 260); 7, 26, 11. W. 41 Fluor, Fowey Consols. 42 ,, Dolomite, Huel Owles. 43 Hornstone, Fluor, Beeralstone. 44 Chlorite, Magnetite, North Roskear. Fox, F.R.S. (Rep. R. C. P. S., 1845, pp. 2, 7). Group 6. Pseudomorphs by infiltration. 45 ,, Tresavean. 46 ,, Albite, Consolidated Ms. 47 ' Axinite, St. Just.(?) In the form of Locality. 48 ,, ,, Dartmoor. 1 Cassiterite, Felspar, Huel Coates. 2 Quartz, Fluor, Consol. Mines. 49 Chalcopyrite, Blende, Levant. 50 ' Huel Alfred. Sometimes " the infused portion of Tin- 51 Chalybite, Levant. stone has not sufficed to fill the cavity left by the Felspar, in which case crystallization has 52 ,, Fahlerz, 53 ,, Crinnis. taken place, and the Tinstone has assumed its ordinary form." (W. M. Tweedy, Rep. 54 ,, Chalcocite, ,, 55 Dolomite(?)H\iel Tolgus. Roy. Inst. Corn. 1841, p. 39.) AUTHORITY. 2, R. W. Fox, F.R.S. (Rep. 56 ,, St. Just. 57 Malachite, Cent-suite, Near Redruth. 58 Halite, t Near Blackbrook R C. P. S., 1845, p. 2). 59 M ? Near Sidmouth. Group 7. Pseudomorphs after organic 60 Finite, lolite, Breage. forms 61 ,, ,, Lamorna. In the form of Locality. 1 Calcedony. Animal forms, Torquay. 2 Broadhembury. 3 ,, Livermead Head. 4 Paignton Harbr. 6 Shells, Haldon. 62 ,, St. Hilary. 63 Trewellard. 64 , MulvraHill. 65 , TolPedn Pen with 66 ' , St. Michael's Mt. 67 , Tregoning Hill. 63 Jf , Nr. Grampound. 6 Copper, Plants, (!) Treskerby. 7 (?) Gondurrow. 69 , Sennen. 70 Mica, P nite, Nr. Land's End. AUTHORITIES. 1, 2, 5, Prof. Church (Phil- 71 Fluor Felspar Mag., 1864, and private information); 3, 4, W. Pengelley (Trans. R. G. S. C., vol. vii., p. 311); 6, 7, J. Carne (ibid. vol. ii.). AUTHORITIES. l, 6, 8, 11, 14, 17, 20, 24, 28, 29, 30, 40, 41, 49, 51, 52, 57, T. M. Hall, F.G.S. (Min Direct, pp. 130 131); 2, 3, 4, 5, 7, 9, 10, No particulars obtainable 12, 13, 16, 21, 22, 23, 25, 26, Greg and Lettsom 1 Quartz, Fluor, St. Agnes. 2 Gt. Crinnis. p 95, et seq.y, 27, 30, 31 (ibid* p. 255); 32, 33, 38, 42, 53, 67, 70, 71, R. Pearce (Rep. R. I. C., 3 ,, ,, South Caradon. andprivateinf.);15, 18, 19, 43, 44, 54, 55,.T. Carne 4 ,, ,, Cam Brea. (Trails. R. G. S. C., vol. ii.); 69, Prof. Smyth 5 ,, ,, Balleswidden. (private information); 68, De la Beche (Rep. 6 ,, ,, Spearn Moor. on Cornwall, &c.); 58, 59, G. W. Ormerod 7 ,, ,, Trehane. (Rep. Dev. Assoc., vol. iii., p. 78); 45, 60, 67, 8 ,, ,, Perranzabuloe. the author has himself obtained. 82 PSILOMELANE. PYEITES. Many of the pseudomorphs referred to are given on the authoiifcy of several mineralogists, although only one is men- tioned in each case. PSILOMELANE. [Black Hematite. Compact Grey Oxide of Manganese.] Amorphous ; botrvoidal, stalactitic, or massive ; surfaces often smooth; tough; fracture conchoidal, un- even, or even ; lustre metallic, sub-me- tallic, or silky ; dark steel-grey to iron- black ; streak brownish-black and shin- ing ; H. 5-6; G. 4-4-4. B., etc. In matrass yields a little water ; on C infusible ; with borax and soda gives Mn reactions ; soluble in warm HC1, with evolution of Cl. Comp. An impure peroxide of man- ganese of variable composition, often containing baryta and water. No analy- sis of a specimen from Cornwall or Devon is known to the author. LOG. Restormel Royal Iron Mines, in splendid velvet- black stalactitic masses ; Lif ton, near Launceston ; Creva Wood ; St. Minver ; Huel Bucketts ; Pednan- drea ; Huel Tolgus ; and other mines in Cornwall. Black Down and Brent Tor, in fine botryoidal and stalactitic masses ; East Down, Georgeham, West Down, and Viveham, near Barnstaple ; near Bideford; Orleigh Court, Buckland Brewer ; Blackdown ; Upton Pyne, near Exeter ; Chudleigh ; Ashton, &c. It also occurs in Ireland, Germany, Nor- way, North America, &c. Obs. It usually occurs associated with Manganite, Pyrolusite, and Wad. Some Cornish specimens occur in concentric layers, alternating with Pyrolusite or Wad. It may be easily distinguished from Pyrolusite and Wad by its hardness; from Hematite by the colour of its streak; and from Magnetite and Pitchblende by its reactions with soda and borax. Purple Copper. See Erubescite. Pyramid. A solid figure, whose base is any right-lined figure, and whose sides are all triangles. A pyramid in crystal- lography comprises two such figures, piaced base to base, i.e., a double pyra- mid. Fig. 1, the octahedron, is a pyra- mid with square base, the sides of which are equal equilateral triangles. PYRARGYRITE. sometimes dendritic, micaceous, dissemi Dated, or massive ; brittle, or almost sec- tile ; fracture conchoidal or uneven ; trans- lucent to opaque ; lustre sub-metallic, adamantine, or resinous ; dark red, lead- frey, or iron-black ; streak dark red ; H. -2-5; G. 57-5-9. B., etc. In matrass decrepitates, and gives a reddish sublimate ; on C fuses at j 1, gives off a sulphureous odour, deposits a copious white incrustation of oxide of antimony ; after long roasting yields a bead of Ag ; insoluble in HC1 ; decom- posed by HNO 3 ; the powder becomes black if treated with KHO. Comp. Anhydrous sulphide of silver and antimony. With silver 59 '9 percent., j antimony 22'5 per cent., and sulphur I 17 "6 per cent, its formula may be | SbAgsSs or SbAgs 3 . Loc. Huel Herland, formerly, in small i crystals, and granular ; Mount Mine ; j North Dolcoath ; Dolcoath ; Huel Mexi- i co ; Huel Ludcott ; Holmbush ; Huel Brothers ; Huel Duchy, Callington, in a i cross-course, both crystallized and mas- sive, with native silver, native c.ipper, and black sulphide of silver. It has been found sparingly in Sark, also found in France, Germany, Chili, Peru, and other . foreign localities. Obs. It may be readily distinguished from Cuprite by its blowpipe reactions ; i from Chalcocite and Galena by its streak ; ; from Tennantite by the crystalline form j of the latter. Angles. e e' = 137 58' a a' == 120 00' eR 144 21 PYRITES. [Dark Red Silver Ore. Antimonial Sil- ver Blende. Rubin-Blende (in part).] Hexagonal ; in prisms variously modified, and of ten macled (Figs. 213, 214); cleav- age rhombohedral, perfect (R = 103 42'); [Iron Pyrites. Mundic. Sulphide of Iron.] Cubic ; in forms resembling Fi-s. 1, 2, 4, 8. 9, 16, 32, 43, 45, 46, 47, 48, 50, i 52 ; the faces often striated or rough ; j macles like Fig. 58 not uncommon ; often j drusy on other minerals ; also massive or compact ; sometimes spheroidal, bo- ; tryoidal, radiated, stalactitic, fibro-la- mellar or cellular ; brittle ; tough ; frac- j ture conchoidal, uneven, or splintery ; opaque ; lustre metallic, splendant, sometimes shining or glimmering; brass- yellow ; occasionally greenish-yellow or ( iridescent ; streak black or greenish- j black ; H. 6-6 5 ; G. 4'S-51 ; gives off a I sulphureous odour when broken, and is | hard enough to give sparks when struck i with steel. Var. 1. Auriferous Pyrites is a varie- I ty containing a notable proportion of gold. PYEITES. PYBOLUSITE. 83 2. Argentiferous Pyrites contains sil- ver. 3. Hepatic Pyrites is a variety of a brown colour, and partially converted into Limonite. B., etc. In matrass gives a sublimate of S, which readily melts into brownish- yellow drops; turns black; on C fuses at I, burns with a blue flame, forms a dark brittle magnetic globule, with a crystalline surface when cool; with borax gives Fe reactions ; scarcely acted upon by HC1, nor by HISTO^ until finely pow- dered, when it dissolves, forming a green- ish-yellow solution. Comp. Anhydrous per-sulphide of iron. Common as it is, but few or no analyses of Cornish or Devonshire spe- cimens are on record, at least within the knowledge of the author. With sulphur = 54 '25 per cent. , and iron 45 "75 per cent, the composition would be indicated by FeS 2 . LOG. Fine specimens have occurred from time to time at Botallack, Levant, Huel Spearn, and other St. Just mines ; at Providence Mine and West Poldice ; Huel Darlington ; Mount Mine ; Great Work, Godolphin, Huel Vor, and other mines in Breage (Figs. 2, 43, and 45, im- bedded in chlorite, as well as other forms); Huel Herland, Gwinear ; Huel Trannack ; Huel Prospidnick, Sithney, in chlorite (Fig. 45); Cadgwith ; Bellu- rian Cove, near Mullion, in a conglo- merate, with native copper ; Dolcoath, Cam Brea, Tincroft, East Pool, and most of the mines in Camborne and Illogan ; Huel Unity, Ting Tang, Tresavean, and most of the mines in Gwennap ; Huel Buller, Copper Hill, Pednandrea, and other Redruth mines ; Creegbrawse ; Huel Jane ; Huel Falmouth ; Nangiles ; Re- tallack, Huel Golden, and other mines in Perranzabuloe ; St. Agnes, magnetic, in cubes? of one inch, formerly (J. Garby, Trans. R. G. S. C., vol. vii., p. 82); Fovvey Consols ; Polgooth ; Lanescot ; Crinnis ; Pembroke ; Great Dowgas ; Huel Maud- lin ; Herodsfoot ; Huel Maria, in chlo- rite, deeply striated and iridescent. Huel Friendship ; Combemartin ; Vir- tuous Lady, Bedford United, and other mines near Tavistock ; Huel Robert, Sampford Spiney ; Parracombe, in trap ash ; Bishop's Tawton, Venn, Bicking- ton, Viveham, and other places near Barnstaple, disseminated in the rocks ; near Tiverton, in a quarry, in the inte- rior of fossil shells ; in the cliffs to the west of Axmouth, &c. Stalactitic Pyrites occurs at East Pool and other localities. Pyrites occurs pseudomorphous after calcite near Tavistock and other places ; after fluor at Beeralstone, &c.; after albite at the Consolidated Mines, Gwen- nap, &c. See Pseudomorphs. Obs. It is, in small quantities at least, almost universally distributed in metal- liferous districts ; few mines being abso- lutely without specimens. It may be readily distinguished from Gold by its hardness and brittleness ; from Chal- copyrite by its hardness ; from Marcasite it can only be distinguished with cer- tainty by its crystalline form (Marcasite is, however, said to be more often radi- ated and fibrous, of a paler colour, often greenish, and much more liable to de- composition. It is largely used in the manufacture of sulphuric acid. A nyles. 00 = 109 28' e o = 140 16' a a 90 00 ov 157 47 o a 125 16 k o 160 32 ae 153 26 kk 148 50 The cube Fig. 2, octahedron Fig. 1, pen- i tagonal dodecahedron Fig. 43, and Figs. j 45, 46, 47, 48, 52 are the most common I forms. Pyritous Copper. An old name for Chalcopyrite. Pyro-electric. Minerals which become electric by heating are so called. Ex. Tourmaline. PYROLUSITE. Black Oxide of Manganese. Anhy- drous Bin oxide of Manganese.] Rhom- bic ; rarely crystallized distinctly ; some- times in crystals, like Figs. 136, 137 ; a Cornish specimen in the author's collec- j tion like Fig. 242 ; botryoidal, reniform, : columnar, fibrous ; massive, compact, ' granular, or earthy ; brittle ; fracture I uneven ; opaque ; lustre metallic, sub- ! metallic, or silky ; steel-grey, to iron or J bluish-black ; soft enough to soil the fingers when handled; H. 2-2 '5 ; G. 47-5-0. B., etc. In matrass unchanged, or gives off a little water: onC unchanged, or turns reddish ; with soda arid borax gives Mn reactions ; soluble in HC1, with evolution of Cl. Comp. Anhydrous manganic dioxide, with often small quantities of oxides of j iron and baryta AVhen pure the com- position will be manganese 63 '3 per cent., oxygen 36 '7, when the formula may be written Mn 2 or Mn 2 O 3 . LOG. Tregony, Very an ; Restormel ; Indian Queens, Creva Wood, Callington ; Lifton and Trebartha, near Launceston ; 84 PYEOMORPHITE. PYROXENE. Tresweeta, St. Stephens ; near Calstock ; and most of the manganese mines of East Cornwall. Tavistock ; Brent Tor (on Psilomelane); Upton Pyne, near Exeter ; Georgehamand Viveham, near Barnstaple ; Newton St. Cyres, Doddiscombleigh, and Ashton, near Chudleigh ; and other Devon loca- lities. (" Manganese" occurs near Buck- f astleigh ; Dean Church, south of Buck- fastleigh; LewTrenchard ; Leigh Down ; East Cot Beacon ; Higher Chillaton ; Narracol ; "VVick ; Bowdon Down, south of Marystow, &c. See Ordnance Map. ) Foreign localities very numerous. (>bs. It may be distinguished from Psilomelane and Manganite, with which it is usually accompanied, by its inferior hardness ; from Antimonite and Jameso- nite by its infusibility. It is largely used in the preparation of chloride of lime, for bleaching purposes; and for glass making. A riffles. MM' = 93 40' MO= 90 00' Od 128 45 P YROMORPHITE. [Brown Lead Ore. Green Lead Ore. Phosphate of Lead] Hexagonal; in horizontally striated prisms, with the terminal edges often replaced, and the basal plane concave or rough (Figs. 188, 190, 192); also globular, reniform, botry- oidal, or massive ; brittle ; fracture im- perfei-t conchoidal ; semitransparent to translucent on thin edges only ; lustre resinous to adamantine ; splendanfc to glimmering; various shades of green, grey, yellow, or brown ; streak white, or pnle yellowish, or greenish-brown ; H. 3-5-4; G. 6-5-71. jB., etc. In matrass darkens ; on C fuses at 1 to a bead which crystallizes suddenly on cooling, tinging the flame green on the edges ; with soda yields a bead pf Pb ; sometimes gives off an allia- ceous^ odour ; when fused with oxide of copper yields a beautiful blue flame ; in- soluble in HC1 ; soluble in HNO 3 . Comp. Anhydrous chlorophosphate of lead No analysis of a specimen from Devon or Cornwall is known to the author, but foreign specimens yield nearly 15 '6 per cent, of phosphoric an- hydride, 81 "8 per cent, of oxide of lead, and 2 '6 per cent, of chlorine. With these proportions the formula will be similar to that of apatite, viz., 9Pb3P 2 -f PbCl 2 or PgOgPbo/PbCaO. Loc. Very fine crystals, formerly, at Huel Alfred, and Huel Hope (mostly changed into galena); more recently at Huel Rose and Hnel Penrose, Sithney ; Penberthy Croft; Huel Bell ; Huel Kea; Huel Falmouth ; Huel Golden ; Beer- alstone, in grey masses, with mimetite, &c. It is found also in Derbyshire, Yorkshire, Cumberland, Wales, and many foreign localities. <>bs. The phosphoric anhydride is very frequently replaced in part by arsenic anhydride, especially in the yellow, grey, or brown specimens. Sometimes the lead is largely replaced by lime, when the sp. gr. is much below that given above. Angles a a' = 120 00' O x = 139 38' Oa 90 00 xx' 142 12 xa 130 22 ba 150 00 Pyrophosphoric. A term applied to substances which " phosphoresce " on heating. Ex. Fluor, especially Chloro- phane. PYROXENE. [Augite. Diallage, in part. Malaco- lite Sahlite ; &c.j Oblique ; when crystallized usually in modified prisms (augite like Figs. 160, 161); cleavage par- allel to M, tolerably perfect ; the faces a b often striated longitudinally ; macles not uncommon ; brittle ; fracture con- choidal or uneven ; sometimes transpa- rent, but more usually translucent or opaque ; lustre vitreous, sometimes co- lourless, but more usually grey, green, dark brown, or black ; streak white to grey; H. 4-6; G. 3 '2-3 '3. Var. 1. Augite. Often dull, dark green, or nearly black, and opaque ; usually fusible at about 2. Usually con- tains notable quantities of alumina. 2. Diopside. Green and transparent ; very brilliant. 3. Sahlite. Often greyish. 4. Diallage. Diallage Metalloide, Schiller-Spar, Bastite, is perhaps the same ; lamellar, greyish or brownish ; curved cleavages ; sometimes classed with Hypersthene. H. = 4. See also Schiller-Spar. 5. Bionzite. Very similar, but darker and less fusible. S^e also Hypersthene. 6. Saussurite (which see) is, perhaps, a variety. 7. Smaragdite is grass-green ; H. 5 ; G. 3-31. Many other varieties have been distin guished. B., etc. In matrass scarcely changed; on C most varieties fuse quietly at about 2 (some intumesce somewhat) to a glassy bead ; with borax and micro, give Fe re- actions ; scarcely soluble, however, in micro. ; the light varieties become pinkish PYROXENE. QUAETZ. 85 if treated with Co; scarcely affected by acids, except when in fine powder ; a long digestion (sometimes partially de- composes it. Comp. Anhydrous silicate of Mg, Ca, and other bases. No analysis of a Bri- tish specimen is known to the aiithor, but foreign specimens sometimes yield about 55 '0 per cent, of silica, 25 '7 of lime, and 18 "6 of magnesia. With these proportions the formula might be written CaSiMgSi or CaSiO 3 + MgSiO 3 or Si 2 O 2 Cao"Algu". Loc. a. Augite. Rocks north of Bo- tallack, and Huel Cock. b. Bronzite. Coverack Cove, of a dark brown colour, in serpentine. c. Diallage. In "'Diallage Rock" at Coverack Cove, Crousa Downs, G winter, and many other parts of the t>t. Keverne district ; the Manacles ; &c. d. Smaragdite is said to have occurred at Coverack (J. Garby, Traus. Roy. Geol. Soc. Corn., vol. vii., p. 76). Ob*. Pyroxene in its various forms is a common mineral in crystalline lime- stones and dolomites, serpentines, vol- canic rocks, &c. ; it ocours also, but less abundantly, wi'h granitic rocks and me- tamorphic schists. The pyroxene of limestones is mostly white, light green, or greyish ; that of most other metamor- phosed rocks although sometimes color- less, is usually green of various shades, from pale green to greenish-black : that of serpentine sometimes occurs in tine crystals, often of the foliated green kind called "Diallage;" that of eruptive rocks is the black, or greenish-black "Augite." "Lime is a prominent ingredient in all the varieties of Pyroxene, while it is wanting, or nearly so, in some (most?) of those of Hornblende." "In Pyroxene, columnar and fine fibrous forms are un- common ; in Hornblende, exceedingly common." (Dana, System of Min., 1868.) It really seems as if the many varieties of so-called Pyroxene, Amphibole, Hy- persthene, &c. are still too little known to allow of a rational classification. They sliould, perhaps, form one great group, only divisible into sub species. Descloizeaux separates ttionzite "da Cap Lizard, Cornouailles," and Hypers- thene from Diallaye and Pyroxene on ac- count of their c> ystaltoyrafitac and opti- cal characters. A tiyles. MM' = 87 06' ab = 90 00' Ma 133 55 sb 119 44 Mb 136 27 ss 120 31 PYRRHOTITE. [Pyrrhotine. Magnetic Pyrites.] Hex- agonal, in prisms, with perfect basal cleavage, but very rarely crystallized ; usually massive ; lamellar, granular, compact or disseminated ; i>rittle ; frac- ture uneven ; opaque ; lustre metallic ; bronze yellow, with often a reddish or brownish tarnish ; streak greenish or greyish-black; H. 3'5-4'5; G. 4'4-7 ; sightly magnetic. B., etc. Jn matrass yields a yellow sublimate of sulphur ; on C fuse-* at 1 to a grey magnetic globule ; with soda gives Fe reactions ; soluble in warm HC1, with evulution of H. 2 S. Comp. Anhydrous proto-sulphide of iron. The following analysis of a Corn- ish specimen is by Hatchett : Iron 63 '5 Sulphur 36'5 Total lOO'O This agrees almost exactly with the for- mula FeS, but some specimens seem to. have an excess of sulphur. Loc. Botallack ; Levant ; Huel Jane,, Huel Kind, St. Agnes; "Magnetic p\- rites has been found at St. Agnes, in cubic (?) crystals, upwards of an inch in diameter, and also missive, of- a lamellar structure, in this and other localities of the mining districts" (J. Garby); Huel Maudlin, cleavable and massive ; Huel Kit church, near Bodmin (massive). Beeralstone ; Meldon Quarry, ne^ir Oke- hampton. Found also in Wales, Scotland,. Ireland, and many foreign localities. Ubs. It may be distinguished from, Pyrites by its inferior hardness, from Chalcopyrite by its colour and blowpipe reactions, from Pentlandite by its mag- netism and by the absence of nickel. Quartz. A family name which conve- niently includes the following four spe- cies, or sub-species, viz. : 1 QUARTZ, or Hyaline Quartz, 2 JASPER, 3 CALCEDONY, 4 OPAL. These are each described under their re- spective heads. Probably a division of the whole family into (Crystalloid Quartz, including Quartz, proper and Jasper ; and Colloid Quartz,, including Calcedony and Opal, would be the most natural. Jasper seems to be nothing more than ordinary massive quartz rendered opaque by the presence of foreign matter in very variable proportions. This would hardly seem to be a sufficient reason for sepa- rating it, since some well-defined Quartz 86 QUARTZ. QUAETZ. crystals (ferruginous) have been analysed and found to contain as much as 5"0 per cent, of peroxide of iron. Calcedony is evidently distinct from Quartz by its essentially non-crystalline (colloid) character, but as the purest varieties have usually a small proportion of water, are somewhat softer than Hyaline Quartz, are often somewhat lighter, and always partially soluble in solution of caustic potash, it does not seem clear that it should be separated from Opal Flint would probably form a passage to Semi-Opal, and Carnelian. to Noble Opal. QUARTZ. [Rock Crystal; &c.] Hexagonal, in forms like Figs. 203 to 211, 243, &<.; usually in prisms, horizontally striated, sometimes doubly terminated ; more usu- ally singly terminated, with the summit planes very unequally developed ; no distinct cleavage, but sometimes in laterally adherent groups, producing a pseudo cleavage ; parallel or divergent ; not unfrequently macled ; also massive ; compact, granular, columnar, fibrous, cellular, &c.; brittle; fracture conchoi- dal, uneven, or "rippled" in amethyst ; transparent to translucent (Jasper is opaque); lustre vitreous, sub-adaman- tine, or resinous on fracture ; splendant to glimmering ; colourless, or yellow, red, green, brown, purple, black, &c.; streak white; H. TO; G. 2 "5-2 '8, the purest varieties 2 '65; frictio-phosphoric. Far. 1. Rock Crys tal is the colourless crystallized (typical) variety. Cornish, Bristol, Irish, and other so-called dia- monds are rock crystal. The Cornish Diamonds are often obscured by an opaque ferruginous layer when first ob- tained. 2. A methyst is a variety with a pecu- liar "rippled" fracture, which possesses Borne remarkable optical properties. It is usually of a more or less deep violet or purple tint ; in some instances this has been proved to be due to a minute trace of oxide of manganese. "Heintz, how- ever, on analysing a very deep purple specimen from the Brazils, obtained in addition to silica, 0'0187 protoxide of iron, 0.6236 lime, 0'0133 magnesia, and 0'0418 soda, whence he infers that the colour is due to a compound of iron and soda." (Bristow's Gloss. Min. p. 13.) 3. Citrine or False Topaz is a variety tinted of a clear yellow colour with oxide of iron. 4. ferruginous Quartz is the same, but duller, and with less lustre. 5. Cairngorm or Smoky Quartz is a clear transparent variety having a rich smoky-brown tint. 6. Morion is the same, but so deeply tinted as to appear almost black. 7. Hose Quartz, as the name implies, is of a rosy tint, but usually very pale, and often full of cracks. 8. Milk Quartz is bluish-white and nearly opaque. 9. Greasy Quartz is compact and mas- sive, and so-called because of the " greasy" lustre. 10. Sugary Quartz is granular, like loaf-sugar. 11. Cellular Quartz or Floatxtone con- sists of a multitude of small cells, filled with air, and surrounded with very thin films of quartz It is so light as to float on water. Specimens from Pednanrirea and other mines would seem to indicate that it is a pseudomorphous deposit on Fluor Spar, which has now disappeared. 12. Fibrous Q uartz or Cros-course Spar is made up of a multitude of imperfect prisms laid side by side ; the free termi- nations often present crystalline planes. 13. Pra*e is a dark leek-green variety, which occurs massive only. The colour is said to be caused by an admixture of Amphibole. 14. Babel Quartz is a name given to peculiarly formed crystals, like Fig. 209. 15. Hacked Quartz is a crystalline variety of Quartz, with markings on its sides as if "chopped" or "hacked," arising from former partially imbedded crystals. 16. Sta j actitic Quartz "consists of straight stalactites, several inches in length, composed of an aggregation of crystals diverging from a centre (of cal- cedony?), the pyramid of the crystal ap- pearing on the surface." (Phillips's Mineralogy, 1823, p. 7.) 17. Haytorite is rather Calcedony than I Quartz. It occurs in pale brownish crys- I tals, having the form of Datholite, at i Haytor and North Koskear. B., etc. In matrass no change; on C alone, infusible; with soda or borax fuses with much effervescence to a clear glass ; with micro, retains its form ; insoluble I in HC1, HNO 3 , or H 2 SO 4 ; soluble in HF. Comp. Anhydrous silica. With sili- con 48 '94 perjcent. and oxygen 51 '96 per cent., the formula will be SiO 2 . It often contains smalt quantities of various me- tallic oxides. Some very rare instances of crystals of ferruginous quartz from Bo- tallack have yielded as much as 5 per cent of peroxide of iron. QUARTZ. QUARTZ. 87 Loc. a. Rock Crystal. CORNWALL. Fine specimens have occurred at Botal- lack, Boscawen Cliffs, Balleswidden, Spearn Moor, Trewellard, Huel Diamond, and other localities in St. Just ; at St. Michael's Mount; Huel Alfred, Phillack (rhombohedrons); at HerlandaridTrevas- cus, in Gwinear ; at the Lizard, in ser- pentine ; at Swanpool and Mainporth, near Falmouth (the primary rhombohe- dron, more or less perfect, and other forms, in elvan); at Dolcoath (Fig. 243 is a curious example from here); North Roskear, and other mines in Camborne ; at East HuelCrofty, East Pool, and the Cam Brea mines in Illogan (Fig, 208, 211, &c.); Huel Buller, Huel Sparnon, and other mines in Redruth ; the Consolidated and other mines in G wennap (primary rhombo- hedrons and other forms); at Perranzabu- loe (double pyramid without prism); St. Ewe, in slate ; near Caerhayes (primary rhombohedron); at Penlane and Trelow- eth, in St. Columb (with pinite in elvan); East Crinnis, St. Blazey; Restormel, Lostwitbiel ; Huel Mary Ann, Menhe- niot ; at the Delabole Slate Quarries, St. Teath; Tintagel. "They occur in nests in the slate-stone, imbedded in a yellow- ish-white clay, like mud, and sometimes as black as wet soot. The whitish-yellow fluid is decomposed adularia, many per- fect crystals of which are found adhering to the quartz. The black matter is de- composed slate stone." (Man. of Min., Truro, 1825, p. 187.) DEVON. Roborough Downs, Buckland Monachorum (in fine double pyramids); Huel Betsy, near Tavistock ; near Oke- hampton ; Gidleigh, near Moretonhamp- Btead; North Bovey; Combemartin, near Ilfracombe ; Lundy Island, &o. Foreign localities are too numerous to mention. b. Amethyst. Botallack, Huel Bellon, Huel Cock, Bosavern, Levant, Nangisel Cove, Roscommon Cliff, and other St. Just localities ; Huel Uny ; Copper Hill ; j Pednandrea; Huel Tolgus ; East Pool, with pale yellow chalybite ; Great Hewas United, St. Me wan; Polgooth; St. Cleer; St. Ewe, &c., finely crystallized in prisms ; Copper Hill, near Okehampton. c. Citrine. Botallack; St. Michael's Mount ; Cam Brea ; Restormel. d. Ferruginous Quartz. Botallack ; Marazion ; Cam Brea ; Dolcoath ; Res- tormel ; St. Agnes ; North Bovey, in large opaque crystals (like Fig. 210). e. Cainujorm. Trewellard ; North Roskear ; Huel Buller ; St. Cleer ; St. Ewe. f. Morion. Little Bounds, formerly, in brilliant double pyramids ; Huel Ruby ; Fowey, g. Rose Quartz. St. Michael's Mount, in small crystals, with cassiterite ; Huel Bucketts, massive and crystallized, and usually full of cracks. h. Mi'ky Quartz. North Roskear, massive, bluish; Pednandrea; United Mines, Gwennap ; Great Huel Vor, Breage. i. Sugary Quartz. St. Agnes; Mount Hawke ; &c. j. FloaUtone. Huel Alfred ; Cardrew Downs ; Pednandrea ; Relistian, &c. k. Fibrous Qu-i.rtz. Huel Virgin ; Tolcarne; Cardrew Downs; St. Agues; Relistian. 1. Prase. Huel Bellon ; North Ros- kear, dark green and massive. m. Hacked Quartz. Huel Trelawny; East Pool. n. Babel Quartz. Tamar Mines. o. Stalactitic Quartz. Botallack, and Huel Alfred, formerly ; more recently at Pednandrea. Ordinary massive Quartz is common in almost every mine and quarry, while a large proportion of granite consists of imperfect crystals of the same mineral. Many specimens of Quartz from differ- ent localities contain enclosed crystals of schoii and other minerals. A few loca- lities are appended : Enclosing Locality. Rock Crystal, Cassiterite, Huel Diamond. Pyrites, Chalcopyrite, Chlorite, Dolcoath. Hematite, Botallack. Dolcoath. East Pool. ,, Restormel. Amethyst, Schorl, Eoscommon Cliff. Chlorite, Botallack. Quartz, Liquids, Utd. Mines (octa), Virtu. Lady (cubes) Beeralstone(cubes) For the many Quartz pseudomorpha see list of Pseudomorphs. (/&.. The Quartz from copper lodes is said to be rarely transparent. Long nar- row prisms are said to be most common in tin lodes, and almost unknown in lodes containing lead. There is often a pecu- liar brilliancy observable about the quartz from lead lodes, which may be well observed in specimens from West Chiverton, and Huel Rose and Huel Penrose, Sithney. Quartz may be dis- tinguished from other minerals some- what resembliiig it by its degree of hard- ness, crystalline form, brittleness, want of cleavage, and other characters. A ngles. RR = Rz Rb bb 94 133 158 120 15' 44 31 00 bs = bx bz 142 167 141 172 00' 59 47 31 88 RADIATED PYRITES. RHOMBOID. R. See Hematite. Radiated Pyritea. See Marcasite and Pyrites. Radiated Zeolite. See Stilbite. Red Chalk. See Hematite. Red Cobalt Ochre. See Erythrite. Reil Copper Ore. See Cuprite. Red Hematite. Red Iron Ore. Red Iron Ochre. Red Iron Ston. Red Oxide of Copper. See Cuprite. Red Oxide of Iron. 1 g H ,matite. Reddle. ) Red Silver Ore. See Pyrargyrite. Reduced. The conversion of a higher oxide, sulphide, &c., into a compound containing a lower proportion of oxygen, sulphur, &c. , or into the metallic state, either by driving off the metalloid, or, more usually, by adding some "flux" or "reducing agent" to combine there- with. The blowpipe is often used for reductions on a small scale. See "Blow- pipe," par. 5, p. 18. Reduction. The operation of reducing, as when copper is obtained from copper ore, or tin from tin ore, &c. R^diuthite. See Chalcocite. Reflected Light. Light reflected from any surface. When objects are looked "at," and not looked "through," they are seen by reflected light. When looked " through" they are seen by transmitted light. Reniform. Kidney-shaped. Having email irregular rounded prominences like the surface of a bullock's kidney. Replaced. See Modified. Reticulate. Netted. Some specimens of native copper occur in interlaced fibres, and are so-called. RETINITE. [Retinasphaltum.] Amorphous, in rounded or irregular lumps; brittle; fracture imperfect conchoidal, earthy, or uneven ; translucent to opaque ; lustre resinous, glistening, or dull; yellow, yellowish-brown, greenish, reddish, or dark greyish-brown ; streak lighter than colour; H. 1-2 '5; G. 1-1 "2. #., etc. In matrass melts to a clear fluid at a low temperature ; on C burns with a bright flame, and fragrant or aro- matic odour ; insoluble in acids ; partly soluble in alcohol, leaving an unctuous residue ; more readily soluble in ether. Comp. Carbon 76'86 Hydrogen 875 Oxygen 14'39 Total . ., 100-00 ; (J. F. W. Johnston, Phil. Mag. III., 1 XII., p. 500 1838.) The composition is a little indicated in another way as follows : a. b. Resin, Sol. in aloo. 55 '0 ... 59 '32 Bitumen 41'0 ... 27'45 Earthymatter 3'0 ... 13'23 Total 99-0 ... 100-00 a. is by Hatchett, b. by Johnston. Loc. Bovey Tracey", in irregular no- dules, in Lignite. Found also in Hano- ver, with peat, and in the Uuited States. RHODONITE. [Siliciferous Oxide of Manganese.] Oblique; isomorphous with augite (Broulce), anorthic (Greg and Lettsom) ; oryst ils very rare ; clea\ ag * perfect clino- diagonal ; usually massive ; compact or granular ; brittle ; fracture flat conchoi- dal or uneven ; translucent to opaque; lustre vitreous to pearly ; rose-red to reddish -brown, or greenish ; sometimes a dark tarnish from exposure to light ; streak very light or white ; H. 5-6 ; G. 3-4-3-7- /?., etc. In matrass slightly darkens ; on C turns brown, and fuses to a dark globule with a strong heat ; with borax gives Mn reactions ; soluble except the silica in strong HC1 if finely powdered. Comp. Anhydrous silicate of manga- nese. With silica 46 '0 percent, and prot- oxide of manganese 54 '0 per cent, the for- mula may be written MuSi or MnSiO 3 or SiOMno". Loc. At a manganese quarry, li mile south-east of Callington ; Creva Wood, I near Callington ; Trebartha ? Indian | Queens? Veryan ? Blackdown, with ; manganite and psilomelane ; Upton | Pyne. Found also in Germany, Italy, Sweden, Siberia, and many other foreign \ localities. Rhomb. A four-sided plane figure, . whose sides are equal straight lines, but i whose angles are not right angles. Rhomb Spar. See Dolomite. Rhombic Dodecahedron. A solid i twelve-sided figure, belonging to the cubic, syxtem, in which each face is a ; rhomb (Fig. 3). Rhombohr dral Iron Ore. See Hema- tite. Rhombohedral Iron Pyrites. See Pyr- rhotite. Rhombohedron. A solid figure, bound- ed by six equal rhombs. See Fig. 197. Rhomboid. A plane four-sided figure, the opposite sides of which only are equal, and whose angles are not right angles. ROOK COEK. SCHEELITE. Rock Cork, Taper, Wood, &c. See Amphibole. Rock Crystal. See Quartz. Kock Marrow. See Lithouiarge. Ruby Silver. See Pyrargyrite. RUTILE. Pyramidal ; in small prisms or pyra- mids, often macled, striated, or uneven, and having a general resemblance to crystals of cassiterite (Figs. 61 to 71); two tolerably perfect cleavages ; often imbedded or massive ; brittle ; fracture conchoidal or uneven ; translucent to opaque ; lustre adamantine or sub-me- tallic; splendant to glimmering ; brown- ish, reddish, yellowish, or blackish ; streak light brown; H. 6 '0-6 '5: G. 4-2-4-8. B., etc. Like Anatase. Comp. Titanic anhydride, like Ana- tase and Brookite. Loc. It is said to have been found in the slate quarries of Delabole, in hair brown threads, imbedded in quartz crys- tals, or in four or six-sided prisms, lon- gitudinally striated; and at Tintagel cliffs, in brilliant prisms, imbedded in transparent quartz. 8, Saponite. See Steatite. SA USSURITE. Anorthic ? sometimes cleavable in two directions, making angles of 124 ; tough ; fracture splintery or uneven ; translucent to opaque ; lustre glimmering ; greyish- white, green, red, brown ; streak white ; H. 5-6; G. 2-7-3-4. B. , etc. In matrass unchanged ; on C fuses at 4 to a greyish enamel ; insoluble in acids except HF. Comp. Anhydrous silicate of alumina, lime, and magnesia. The following analy- sis of a specimen from Coverack, is by Dr. Thomson : Silica 82168 Alumina 5'072 Oxide of iron and manganese 2 "880 Lime 5'520 Magnesia 4'520 Potash . trace Total 100160 Loc. Coverack and Kynance Coves, and Gwinter, in the Lizard district, with diallage rock. It is, perhaps, the so- called Jade of that neighbourhood. Scalenohedron. A solid figure, bound- ed by twelve equal scalene triangles, as in Fig. 217. It is a common form of calcite in some districts. SC A POLITE. [Meionite. Wernerite.] Pyramidal, with perfect prismatic cleavage ; often massive and compact ; brittle ; fracture conchoidal ; translucent to opaque ; lustre vitreous, resinous, or pearly on cleavage ; colourless, white, grey, green- ish, reddish, brownish ; streak white ; H. 5-0-5-5; G. 2 "6-2 '8. B., etc. In matrass unchanged ; on C melts at 3 to a transparent glass ; treated with Co turns blue ; soluble with effer- vescence in borax or micro. ; decomposed, in powder, by HC1. Gomp. Anhydrous silicate of alumina and lime. No analysis of a British spe- cimen is known to the author, but foreign specimens contain from 37 to 54 per cent, of silica, 25 to 35 per cent, of alumina, and 9 to 24 per cent, of lime. Loc. A little south of the village of Chagford, in a narrow vein of granite, with felspar, schorl, quartz crystals, and calcedouy. It was found in the year 1868, by Mr. G. W. Ormerod, F.G.S., and occurred in a mass as large as the palm of the hand (Rep. Dev. Assoc,, vol. III., p. 80, 1869). SCHEELITE. [Tungstate of Lime.] Pyramidal; in attached or imbedded four-sided prisms, usually more or less modified (Figs. 86, 87, 88); with some faces striated, rough, or curved; sometimes reniform, columnar, or massive ; brittle ; fracture conchoidal or uneven ; translucent to opaque ; lustre vitreous, resinous, or adamantine; colourless, greyish, yellow- ish, reddish, brown, or green ; streak white or slightly tinged; EL 4-4 "5; G. 5-9-6-2. B. , etc. In matrass no change, or de- crepitates only ; on C decrepitates and becomes opaque ; fuses at 4, or infusible ; soluble in HC1 or HNO 3 , except yel- low tungstic anhydride, which sepa- rates ; soluble, except the lime, in KHO ; yellow tungstic anhydride is precipitated on addition of HC1 or HNO 3 . Comp. Anhydrous tungstate of lime. A specimen from Pengelly Croft yielded to Klaproth the following results, viz.: Lime 18'70 Tungstic anhydride 75 '25 Silica 1-50 Peroxide of iron 1"25 Peroxide of manganese "75 Total 97-45 With tungstic anhydride 81 '0 per ceiit. 90 SCHEEL OEE. SCOKOBITE. and liine 19 per cent, the formula may be written CaW or CaWO 4 or W0 2 Cao". Loc. Pengelley Croft, Breage, former- ly, in a tin lode ; Huel Maudlin ; Huel Friendship, in fine octahedrons of a rich yellow colour, imbedded in chlorite, and occasionally associated with wolfram the crystals formerly met with at this locality were sometimes 1 inch long. It is found also in many foreign locali- ties. Obs. Like other ores of tungsten, Scheelite is characterised by a high sp. gr. It was in this mineral that tungstic anhydride (acid) and tungsten were first discovered by Scheele. Anqles. PP = 100 40' PF 129 02 Pe 140 10 Px 151 34 Scheel Ore. See Wolfram. ee = 108 12' ee' 112 02 e y 171 30 SCHILLER SPAR. [Diallage-metalloide. Bastite .] Oblique, or anorthic ; one very perfect cleav- age ; brittle ; fractuie uneven or splin- tery; translucent to opaque; lustre pearly, sub-adamantine, or sub-metallic ; greenish, yellowish, or brownish ; streak nearly white ; H. 3 '5-4; G. 2 '6-2 '8. /?., etc. In matrass yields water, which has often an alkaline reaction ; on C becomes brown and often magnetic ; fusible at about 4 ; with borax gives re- actions for iron or chromium ; decom- posed by H 2 SO 4 ; less completely by HCL Coinp. Hydrated silicate of magnesia and other bases. No analysis of a Bri- tish specimen is known to the author, but foreign specimens contain about 43 per cent, of silica, 26 '0 per cent, of mag- nesia, 12 '0 per cent, of iron, and 12 '0 per cent, of water. Loc. Coverack, Gwinter, Kildown near Cadgwith, Kennick Sands, and other parts of the Lizard district, im- bedded in a serpentinous rock. Obs. Its composition and peculiar properties, need special investigation. It should, perhaps, be regarded as a sub- species of Pyroxene. Perhaps several distinct minerals have been described under this name. Schist. An imperfectly foliated rock, which splits up into thin irregu'ar plates. The Cornish and Devonshire killas is Schist. Mica-Schist occurs in the neigh- bourhood of St. Ives and other places. Schorl. See Tourmaline. SCHROTTERITE. Amorphous ; compact ; massive ; brit- tle ; translucent to nearly transparent ; lustre resinous or greasy ; white, more often greenish, yellowish, or spotted with brown ; streak white ; H. 3-3 "5; G. T9- 21. B. . etc. In matrass yields much water ; on C becomes a white opaque infusible mass ; with Co turns a fine blue colour ; decomposed by HC1. Comp. Hydrated silicate of alumina, like Allophane, but with less silica. Dana gives about 12 per cent, of silica for Schrotterite, and 20 '0 per cent, for Allophane. Loc. Cornwall (Dana). See remarks on Allophane, p. 3. SCORODITE. [Martial Arseniate of Copper.] Rhom- bic ; in globular groups of small crystals, shewing faces of the prism and pyramid (Fig. 244); perfect cleavage parallel to M ; often drusy on other minerals ; rarely compact ; brittle ; fracture uneven ; se- mi-transparent to translucent on edges only ; lustre vitreous, resinous, or ada- mantine ; streak white or nearly so ; pale green, bluish, brownish ; dichroic ; H. 3-5-4; G. 31-33. J3., etc. In matrass gives off water and turns yellowish ; with a strong heat yields a white crystalline sublimate ; on C melts to a grey magnetic slag with metallic lustre ; gives off strong alliaceous fumes ; soluble in HC1 ; partly soluble in KHO, the residue turning brown. Comp. Hydrated arseniate of iron. A Cornish specimen yielded the follow- ing results to Damour : Arsenic anhydride 51 "06 Peroxide of iron 32 '74 Water 15'68 Total 99-48 With arsenic anhydride 49 "8 per cent., peroxide of iron 347 per cent., and water 15 "5 per cent, the formula may be written Fe 2 As 2 4H 2 or FeAsO 4 + 2H 2 O or As 2 O 4 Feo" 2 + 4OH 2 . Loc. Huel Muttrell, Huel Unity, Huel Gorland, Carharrack, and Tincroft (Phil- lips's Mineralogy, 1823, p. -321); recently in minute pale greenish blue crystals, on calcedony, from Pednandrea ; St. Aus- tell, lining cavities ("vugs' r )in tin lodes, in pale bluish-green radiating groups ; Crinnis. Found also in France, Ger- many, Brazil, and other foreign localities. Obs. It may be readily distinguished from the arseniates of copper, some of SEOTILE. SERPENTINE. 91 which it much resembles, and with which it is often associated, by its blowpipe re-actions. Angles. M M' = 98 02' M r = 145 29' Ma 130 59 r r' 114 34 Mb 130 09 Sectile. Those minerals are termed sectile from which when cut with a knife the fragments do not fly away in powder. They are midway between brittle and malleable. Ex. Chalcocite. Selenite. See Gypsum. SENARMONTITE. Cubic ; usually in octahedrons, like Fig. 1, more or less modified ; brittle ; frac- ture uneven or lamellar ; transparent to translucent ; lustre resinous to adaman- tine ; colourless ; streak white ; H. less than 3; G. 5 '2-5 '3. B., etc. In matrass sublimes com- pletely with a strong heat, depositing a white sublimate ; on C volatilizes, and deposits a white crystalline coating ; in K, F is reduced to a brittle metallic bead, especially if mixed with soda or cyanide of potassium; tinges the flame green ; solu- ble in Aqua Regia, but precipitated from the solution on addition of much water ; with H 2 S yields an orange red precipi- tate. Comp. Anhydrous oxide of antimony. Sb 2 or Sb 2 O 3 with, when pure, antimony 84 '3 per cent, and oxygen 15 '7 per cent. Loc. Some of the antimony mines in the east of the county, on Jamesonite, with Bleinierite. It was first observed by Mr. Davis, of the British Museum, who found it in opaque regular octahe- drons in a cavity of Jamesonite, accom- panied with Bleinierite and minute crys- tals of Cerussite, but the author has since found it on specimens of his own. Obs. It is best distinguished from Valentinite by its crystalline form. SERPENTINE. [Ophiolite. Ophite; &c.] Amorphous; massive; fibrous, foliated, granular, or compact ; sectile ; tough ; fracture con- choidal, uneven, or splintery; translu- cent to nearly opaque ; lustre resinous, vitreous, glimmering, or dull ; various shades of green, red, brown, yellow, or nearly white ; often mottled, and con- taining disseminated crystals of Bron- zite or Diallage, and particles of chro- mite or other minerals ; streak white, or slightly tinged as the colour ; H. 2*5-4 (5'5 Bowenite); G. 2 '4-2 '6. Var. The following are the chief of those described by Dana and others, some are, perhaps, distinct species : 1. MASSIVE: a. Noble or Precious Serpentine has a rich oil-green colour and considerable lustre. It is translucent, even in thick pieces. H. 2 '5 to 3'0. b. Retinalite is honey-yellow to light oil-greea ; H. 3'5 ; G. 2 "47 to 2 '52. c. Common Serpentine is sub-translu- ceut, or nearly opaque ; the colours are often dull red or brown ; H. 4'0. d. Porcellaphite is earthy; very soft when first obtained ; smooth porcel- lanous fracture ; H. 3'5 ; G. 2 '48. e. Bowenite. Apple-green to green- ish-white ; fine granular structure ; H. 5'5-G; G. 2-59-279. 2. LAMELLAR : a. Antigorite. Thin, easily separable laminae ; translucent or semi-transpa- rent ; smooth, but not unctuous ; H. 2 '5. It will sometimes cleave into rhom- bic prisms. b. Williamsite. Apple-green > H. 4 '5; G. 2-59-2-64. 3. FOLIATED : a. Maumolite. Thin folise, brittle ; easily separable, or passing into an almost compact variety ; lustre pearly ; green- ish-white or bluish ; G. 2 41. b. Thermophyllite. Small scaly ag- gregations ; light brown, yellow, or sil- very-white ; lustre of cleavage pearly; H. 2-5; G. 261. 4. FIBROUS: a. Picrolite. Almost columnar; not flexible ; not often easily separable ; long splintery fracture ; dark green, greenish- giey, or brown. Metaxite is very similar, but separable into brittle greenish-while columns. b. Chrysotile occurs in easily separable flexible fibres of a greenish- white, yel- low, or brownish color, and silky or sub- metallic lustre ; G. 2 "2. It includes much of the so-called asbestos of ser- pentine rocks. Very many other varieties are de- scribed, mostly from their external char- acter alone. Some writers include Schil- ler-Spar or Bastite with Serpentine. B., etc. In matrass always gives off water, and usually darkens ; on C turns white ; fuses at 4, or is infusible ; with Co often indicates Mg; with borax or micro, yields reactions for Fe, Ni, or Cr ; decomposed by HC1 or H 2 SO 4 , leaving powdery or slimy silica. Comp. Hydrated silicate of magnesia and various other bases, with from 11 '0 i to 16 -0 per cent, of water, 39 '0 to 44 '0 92 SEBPENTINE. SILICATES. per cent, of silica, and 30 '0 to 44 '0 per cent, of magnesia. Of the following analyses a. and b. are of dark green ser- pentine from the Lizard district. "The specimen is of a very dark green colour, in places verging upon black ; it is thickly spotted with red, and has a coarsely gra- nular structure. . . . massive, with- out any indication of foliation." "The microscope shows this rock to consist of a crypto-crystalline base, spotted by oxide of iron, &c., and enclosing indis- tinct green or yellowish-brown crystalline forms, pseudomorphs after pyroxene?" (J. A. Phillips, Phil. Mag., Feb., 1871): a. b. Silica 38-86 ... 38'58 Alumina 2'95 ... 3'06 Ferric oxide 1'86 ... T95 Ferrous oxide 5 '04 ... 510 Chromic oxide '08 ... 0'08 Oxide of nickel 0'28 ... 0'30 Oxide of manganese trace ... trace Lime trace ... trace Magnesia 34'61 ... 34'52 Potash 033 ... 0'30 Soda 077 ... 076 Water 15'52 ... 15'52 Total 10030 . 99-97 Sp. gr 2-59 ... 2-59 With 43-7 per cent, of silica, 43 '3 per cent, of magnesia, and 13 "0 per cent, of water the formula may be written 3Mg2Si2H 2 or 2MgSiO 3 + MgH 2 O 2 + H 2 O orSi 2 Mgo"gHo 2 + OH 2 . A dark green serpentinous rock from Clickor Tor yielded to the same che- mist : a. b. Silica 36-60 ... 38'80 Titanic acid trace ... trace Phosphoric acid ... trace ... trace Alumina 17 '58 ... 17'CO Ferric oxide 141)8 ... 1510 Ferrous oxide 4 "52 ... 4 '50 Chromic oxide 014... 014 Oxide of manganese trace . . . trace Lime 5'04 ... 4'92 Magnesia 5'97 ... 6 '04 Potash trace ... trace Soda 0-84 ... 0-85 Water 10 '66 ... 10'46 Total 98-43 ... 98'41 Sp. gr 277 ... 277 Mr. Phillips observes : " The micro- scope shews this to be a highly metamor- phosed rock, consisting of an amorphous matrix porphyri tic ally enclosing yellow- ish-brown or green patches with indis- tinct crystalline forms, which are evi- dently pseudomorphs. There are also ' many black grains of magnetite, and crystals of some pyroxenic minei-al pro- bably Schiller-spar or diallage (ibid). Loc. Cadgwith, Kynance, Goonhilly Downs, Coverack, and many other lo- calities in the Lizard district yield good specimens ; Duporth, west of Charles- town ; Tregarthen; Gorran ; St. Cleer and Clickor Tor, near Liskeard ; Polla- phant, near Launceston ; &c. It occurs also in Anglesea, Scotland, Ireland, and many foreign localities. Obs. Serpentine should, perhaps, be regarded rather as a rock than a mineral. It often contains veins of steatite or cal- cite, and its joints often contain native copper. Crystals of Diallage or Bron- zite, and minute particles of Chromite, Magnetite, Pyrites, and other minerals are often disseminated through it. Siderite. See Chalybite. Silicates. Compounds of silica with various metallic oxides are so called. They are very numerous, and often very difficult to distinguish from each other by any means short of chemical analysis. Dana divides the silicates into groups according to the oxygen ratio for the " bases " and silica, into Base. Silica. 1. Uni-silicates =11 2. Bi-silicates =12 3. Sub-silicates = 1 i J, f, &o. In the blowpipe or pyrognostic exami- nation of silicates the chief points to be noted are : 1. Whether moisture is given off on heating in matrass (hydrated silicates). 2. Whether the moisture has an acid reaction (Fluorine) or alkaline (probably some altered mineral). For fluorine, test specially with "Brazil- wood paper," and also observe whether the inside of the tube is roughened, &c. 3. Whether the specimen is fusible when heated on charcoal, and in what degree, or remains infusible. (If it be- comes magnetic, iron is indicated; such silicates are usually fusible). 4. Those which leave a white or nearly white residue after heating on charcoal, or in forceps, may be treated with Co. for detection especially of alumina and magnesia. If a blue colour is produced, alumina is indicated ; if .pink or red, magnesia ; if green, zinc. 5. When the specimen is neither colour- less nor nearly white after strong heat- ing, it should be tested for metallic oxides by means of borax or micro. 6. Silicates of copper (Chrysocolla and Dioptase) will yield a bead of copper if treated with soda. SILICATE OF TIN. SMALTITE. 93 7. Sulphur may be detected in sili- cates by fusion with pure soda, after which the moistened assay is to be laid upon a polished plate of silver, or sil- ver coin, when a dark spot will be pro- duced if sulphur is present. 8. In forceps observe whether the tip of the OF is coloured (Soda, Potash, Lithia, Baryta, Strontia, &c.) 9. For fusibility try both OF and RF. Many silicates which are infusible_ in OF are fusible in RF by the peroxides changing to protoxides. 10. Many silicates are soluble in HC1 if finely powdered, except a quantity, more or less, of silica, which separates as a gelatinous mass or slimy powder. 11. Nearly all silicates effervesce when heated with soda. Most are freely solu- ble in borax, but leave a skeleton of silica if heated with micro. Upwards of 40 of the Cornish and Devonshire minerals are silicates. A few, such as Orthoclase and Chlorite, are very common ; but very many, as Topaz, Beryl, Stilbite, &c., are extremely rare. Silicate of Manganese. See Rhodonite. Silicate of Tin. A massive and crys- tallized pseudomorph after Quartz, from Huel Primrose, St, Agnes (J. Garby, Trans. R. G. S. 0., vol VII., p. 85). Siliceous Oxide of Copper. "Has been found at South Basset, imbedded in gra- nite close to the vein, or in a quartzose rock occurring in the vein. It is black, with a flat coiichoidal fracture, very much resembling flint, and of equal hardness. Before the blowpipe a button of pure copper is, without much difficulty, pro- duced, leaving a siliceous skeleton of great whiteness." (J. Garby, Trans. R. G. S. C., vol. VII., p. 89.) What mineral is here referred to it is difficult to say, as the characters set down do not agree with those of any of the recognised Cornish minerals. SILVER. [Native Silver.] Cubic; sometimes in cubes or octahedrons variously modi- fied (Figs. 1, 2, 8, 9, 10, 11, &c.); often macled ; more usually arborescent, fili- form, or reticulate ; sometimes massive; malleable ; fracture hackly ; opaque ; lustre metallic; silver-white, but often covered with a yellow, brown, or black tarnish ; streak light and shining ; H. 2'5-S-O; G. 101-11. B., etc. In matrass no change ; on C fuses readily to a very bright white me- tallic bead, depositing a dark red coating on the charcoal ; insoluble in HC1 ; solu- ble in HNO 3 ; the addition of HC1 re-pre- cipitates it as a white curdy chloride, which is soluble in ammonia. Camp. The purest specimens almost pure silver. No analysis of a British specimen is known to the author. LOG. Fine specimens were formerly obtained, associated with other silver ores, at Levant ; Huel Herland, Gwin- ear, in a soft rock ; Huel Alfred and Huel Ann, Phillack ; West Huel Dar- lington : Dolcoath ; North Dolcoath ; Huel Basset ; Huel Mexico ; Huel Gold- en Consols ; Great Retallack ; Crinnis ; Huel Ludcott, filiform, with stephanite, recently ; Fowey Consols ; Holmbush ; Huel Duchy ; Huel St. Vincent ; Huel Brothers ; Willsworthy Mine, near Ta- vistock, with erythrite and chalcopy- rite ; Combemartin, in small filaments with galena. It occurs in most foreign localities of silver ores. Obs. It may be readily distinguished from all other minerals by the reactions given above. A ngles. oo = 109 28' a a 90 00' o a 125 16 &c. Silver Black, Silver Glance, Silver Mulm. See Argentite. Silver White Cobalt. See Cobaltite. Slate Spar. See Calcite (Schiefer-Spar). SMALTITE. [Smaltine. Tin-white Cobalt. Arseni- cal Cobalt.] Cubic; in octahedrons or cubes variously modified (Figs. 1, 2, 8, 16, 18, &c.); sometimes macled ; also re- niform, botryoidal, arborescent, reticu- late, disseminated, or massive; brittle; fracture uneven ; opaque ; lustre metal- lic ; splendant to glimmering, or dull ; tin-white to steel-grey; often a dark grey or iridescent tarnish ; streak black, or very dark grey; H. 5 '5-6; G. 6 '4-77; yields an alliaceous odour when broken. Far. Smaltite is the pure cobaltic variety; G. 6 '3-6 '6. Chloanthite is a variety in which the Co is largely replaced by Ni ; G. 7-7 '7. It is often described as a distinct species. B. , etc. In matrass gives a white crys- talline sublimate ; on C fuses atl to a grey brittle bead of metallic appearance; gives off an alliaceous odour, and depo- sits a white coating on the charcoal ; with borax or micro, yields a deep blue bead in both flames ; soluble except ar- senic in HNO 3 , forming a pink (Smal- tite) or green (Chloanthite) solution. Comp. Anhydrous arsenide of cobalt. No analysis of a British specimen is known to the author. With cobalt = 28'23per cent, and arsenic = 7177 per cent, the formula may be CoAs 2 . 94 SMARAGD. SPECIFIC GRAVITY. Loc. Botallack (qy. cobaltite); Wher- , ry Mine ; Huel Herland ; Dudman's ] Mine, Illogan ; Roskrow United, Ponsa- j nooth ; Huel Sparnon, ou quartz, arbo- ; rescent and reticulated ; a solid mass of cobalt ore, probably smaltite, was raised i in Huel Sparnon about the year 1820, I which weighed 1,333 Ibs. (Man. of Min. Truro, 1825, p. 52); East Pool, recently, massive ; Pednandrea ; Dolcoath ; St. j Austell Consols ; Polgooth ; Huel Trugoe, j near St. Columb Major; Huel Huckwor- : thy, Sampford Spiney ; &c. It is also i found in considerable quantities in Ger- many and other foreign localities. Obs. It may be best distinguished j from cobaltite by the grey colour of the crystals, or of a fresh fracture, the ab- ; sence of distinct cleavage, and the ab- j sence or small proportion of sulphur. Angles. oo = 109 28' a a = 90 00' ao 125 16 ad 144 44 &c. Mostly the same as Pyrites. Smaragd. Smaragdus. See Beryl. Smaragdite. A grass -green variety of pyroxene. Said to have been found at Coverack (J. Garby, Trans. K G. S. C., vol. VII. , p. 76). Smell. A character of but little im- portance in determinative mineralogy. Chrysocolla may often be distinguished from malachite by its earthy smell when breathed upon. See also Odour. SMECTITE. [Fuller's Earth.] Amorphous; mas- sive ; sectile ; opaque ; glimmering or dull ; white, grey, green, or brown ; streak white, shining ; xinctuous ; non- adherent ; softens if placed in water ; very soft; G. T2-21. ., etc. In matrass gives off much water; on C infusible (dark varieties fusible); decomposed by HC1. Comp. Hydrated silicate of alumina, magnesia, iron, lime, &c., of very uncer- tain composition. Rather a rock thau a mineral. Loc. Carn Brea, in a copper lode? (J. Garby, Trans. K. G. S. C., vol. VII., p. 76). A similar mineral mass was found at Huel Penrose, Sithney, a few years ago. Sooty Silver Ore. See Argentite (Sil- ver Black). Solubility. A character of very general application and much importance in the discrimination of minerals. A few mi- nerals are soluble, more or less readily, in water. These may be at once known by their possessing a distinct taste. To ascertain the solubility of a miner- al, a little of its powder should be placed in a test-tube and treated with a few drops of the solvent. For general analy- sis, substances which have not a metallic appearance should be treated with vari- ous solvents in the following order until the proper solvent is found. 1. Water. 2. Dilute hydrochloric acid. 3. Strong hydrochloric acid ; warmed if necessary. 4. Dilute nitric acid. 5. Strong nitric acid ; warmed if ne- cessary. 6 Aqua Regia, 7. Dilute sulphuric acid. 8. Strong sulphuric acid. In some cases special solvents, such as caustic potash, caustic soda, ammonia, hydrofluoric acid, &c , may be used. A watch-glass is, for very minute quanti- ties, sometimes more convenient than a test-tube. To ascertain whether any portion of the substance is dissolved in cases where it is not freely soluble, a drop of the sol- vent should be evaporated to dryness on clean glass, or platinum foil, when, if there be any fixed residue, it will be evidence of a certain amount of solution, as these solvents are all volatilized completely by heat : unless, indeed, they be impure. In the case of substances of metallic appearance much time may often be saved by using nitric acid dilute or strong before the other solvents. Any eflervescence, peculiar odour, change of colour, or appearance should be carefully noted. Any undissolved or al- tered insoluble residue must be carefully examined by the blowpipe and other means. Many sulphides, arsenides, or silicates leave residues which are easily recog- nised by their appearance or by a few simple tests. Solvents. See Solubility. Spar. A Cornish term for Quartz. The true spars are such minerals as Cal- cite, Dolomite, Chalybite, Fluor Spar, Barytes, Celestite, &c. Sparable Tin. See Cassiterite. Sparry Iron Ore, Spathose Iron. See Chalybite. Spear Pyrites. See Marcasite. Specific Gravity. This term is used to express the weight of a substance com- pared with some other substance. In mineralogy distilled water at the tem- perature of 60 F. or 15 '55 C. or some- times 4 C. is taken as the standard. Thus the sp. gr. of water is said to be 1 ; that of silver about 10.^ ; meaning that silver is about 10^ times heavier than an equal bulk of water. SPECIFIC GKAVITY. STALACTITES. 95 The specimen to be examined should be free from foreign matter, from disin- tegration, or decay (unless it is the sp. gr. of such a specimen which is especially wanted), and should contain no cavities; when these are suspected the mineral should be powdered. The following methods will suffice for most minerals, the first for such as are in compact masses, the second for small fragments or fine powder: 1st Method : a. "Weigh the fragment as carefully as possible in an ordinary pair of scales. b. Suspend it by a horse-hair from be- low the scale-pan, let it dip under the surface of water contained in any con- venient vessel, and again weigh it. It will be found that fewer weights will be sufficient to balance it. c. Substract the weight indicated in b. from that in a. ; the difference will be the weight of a quantity of water equal in bulk to the specimen. d. Divide the weight a. by the dif- ference, c. ; the quotient will be the specific gravity. Example 1 A specimen of white cal- cedony, from Huel Kitty, St. Agnes : a. Weight in air 431 b. Weight in water 27'2 c. Difference 15'9 431 -T-15'9 = 271, the sp. gr. of the specimen. Example 2 Green fluor, from Gwen- nap : a. Weight in air 135'3 b. Weight in water 92'0 c. Difference 43'3 135-3 = 3 "125, the sp. gr. of the specimen. 43-5 2nd Method : Procure a small specific gravity bottle, a light glass bottle with a mark on the neck ; or, better, a stopper perforated with a fine hole. a. Fill it with water, insert the stop- per, and wipe it dry. Make a counter- poise the exact weight of the bottle so filled. b. Weigh off any convenient quantity of the substance to be examined, such that it may be afterwards introduced into the bottle. c. Put the weighed fragments carefully into the bottle, taking care that none be lost. Of course, as the bottle was pre- viously full of water, some will now run out. Having again inserted the stopper and wiped the bottle, it will be found that the counterpoise, together with a smaller number of weights than those mentioned in b., will be sufficient to ba- lance it ; the difference will be the weight of the displaced water, i.e., of a bulk of water equal to the specimen. d. Divide the weight of mineral in b by the difference ; the result will be the sp. gr. Example 3 Fine sand from Marazion. 301 grains were carefully weighed out. They were then introduced into a spe- cific gravity bottle ; counterpoised as described ; when it was found that 185 grains were sufficient to produce equili- brium. Then the weight of mineral = 301 grains ; weight when placed in bottle = 185 grains. Difference, or weight of an equal bulk of water 116 grains. Then 301 -^ 116 = 2'6 the sp. gr. re- quired. Specular Iron. See Hematite. Sphene. See Titariite. Sphenoid. A solid figure resembling a tetrahedron, but the sides of which are not equilateral triangles. The hemihe- dral forms of the tetragonal, rhombic, and oblique pyramids are called sphe- noids. The tetragonal sphenoid is bounded by four equal isosceles triangles. The rhombic sphenoid is bounded by four equal scalene triangles. The oblique sphenoid is bounded by four scalene triangles, two larger and two smaller. Spherical. A term applied to those mineral specimens which occur in a form approximating to a sphere, as some va- rieties of Aragouite or Malachite. It is an extreme mammillary form. Stalactites. The cylinders or cones which hang from the roofs of some ca- verns, especially limestone caverns, are so-called. They are deposited by the water which percolates through the roof. As it evaporates, the dissolved carbonate of lime remains behind and so forms a hanging mass. Some havs a granular, some a crystal- line, fibrous, or radiating structure, while some are quite hollow. Fine stalactites of calcedony have occurred in many Cornish mines, especially at North Pool and Huel Alfred, many years ago ; and quite recently at Pednandrea. At the latter locality some of the specimens are surrounded with minute crystals of ordi- nary quartz, so that they have been mis- taken for stalactitic quartz. Stalactites of hydrous oxide of iron are very common in the old workings of many mines. Stalactites of sulphate of iron have oc- curred at Huel Prosper, in old workings. 96 STALACTITIO. STEATITE. Stalactites of psilomelane have oc- curred at Kestormel Eoyal Iron Mines, associated with lithomarge. Stalactitic Minerals which occur in forms resembling icicles are said to be stalactitic. Stalagmites are formed in the same manner as stalactites, but they occur on the floors of caverns. Large dome-shaped masses are sometimes found in old work- ings, and in limestone caverns the cone- shaped stalagmites sometimes so ncrease in size as to meet and join the stalactites depending from the roof, so forming rude pillars. Stanniferous. Containing tin. STANNITE. [Stannine. Tin Pyrites. Bell Metal Ore, &c.] Cubic? pyramidal? or amor- phous; mostly occuring in compact or gra- nular masses ; sometimes disseminated ; brittle ; fracture uneven or granular ; opaque ; lustre metallic ; steel-grey to iron-black ; sometimes yellowish; streak black; H. 4 ; G. 4 "3-4 '6. B., etc. In matrass decrepitates and gives off a yellow sublimate ; in open tube gives off SOg, and often deposits a white incrustation of Sn0 2 ; on C fuses readily to a brittle magnetic bead, deposit- ing a white incrustation ; with borax yields the reactions for copper ; decomposed by HNO 3 , forming a green solution, with separation of S and Sn0 2 . Comp. Anhydrous sulphide of copper and tin, with some iron. Many miner- alogists regard it as an intimate mixture only of oxide of tin and chalcopyrite. Of the following analyses a. and b. are of specimens from St. Agnes, by Klap- roth ; c. is from St. Michael's Mount, by Mallet ; d. from St. Michael's Mount, by Johnston ; e. from Huel Rock, by Ku- dernatsch : a. b. c. d. e. Tin 84-0 26-5 26 -85 31 '618 25'55 Copper 36-0 30'0 2918 23'549 29'39 Iron 2'012-Q 673 4791 12'44 Zinc 7-26 10113 177 Sulphur 25-030-529-46 29 '929 29 "64 Gangue 016 1-02 Total 97-0 99-0 99'64 lOO'OOO 99'91 Loc. Botallack ; St. Michael's Mount ; South Huel Crofty, Cam Brea, and East Pool, recently; Barrier (?) Mine, Gwen- nap; Scorrier Consols; Huel Rock and Huel Primrose, St. Agnes ; Stenna Gwynn; St. Stephens; Lanescot It has been found also in Ireland and in Ger- many. STA UROLITE. [Staurotide.] Rhombic; in six-sided prisms (Fig. 116, &c.); orinmacles inter- secting each other, as in Figs. 117, 118 ; brittle ; fracture conchoidal or uneven ; translucent to opaque ; lustre vitreous to resinous ; dull reddish-brown or black ; streak white or greyish ; H. 7-7 '5 ; G. 3-4-3-8. B., etc. In matrass no change ; on C, in fine powder, fuses at 4 to a black or dark green slag; with borax slowly forms a dark green glass ; with micro, a glass almost colourless ; insoluble in HC1 ; partly decomposed by H 2 SO 4 . Comp. Anhydrous silicate of alumina and iron. No analysis of a specimen from Devon or Cornwall has been made, but foreign specimens contain from 28 to 40 per cent, of silica, 44 to 53 per cent, of alumina, 14 to 18 per cent, of peroxide of iron, with, frequently, small quantities of manganese, lime, or mag- nesia. Loc. It is said to have been found in the clay-slate of Cornwall and Devon (T. M. Hall, F.G.S., Min. Direct., pp. 52-63). The figures given may, perhaps, lead to its re-discovery. Obs. It has been found in Scotland, Ireland, and many foreign localities, usually in mica-slate, talc-slate, or clay- slate, with garnet, kyanite, and tourma- line. STEATITE. [Saponite, Dana. Soapstone; &c.] Amorphous ; massive ; sometimes nodu- lar; compact or foliated; sectile; fracture splintery, slaty, uneven, or flat conchoi- dal ; translucent to opaque ; lustre waxy, glimmering, or dull; white, or various tints of grey, yellow red, brown, green, blue, &c.j H. l-2'5; G. 2 '2-2 '8 ; unctuous. Far. The softer varieties are specially called Saponite. B. , etc. In matrass gives much water, and sometimes turns darker; on C fuses at about 4 to a vesicular glass or white enamel ; some varieties infusible ; with Co the infusible varieties often turn reddish ; insoluble in HC1 or HNO 3 ; de- composed by hot H 2 SO 4 , with separation of silica. Comp. Hydrated silicate of magnesia and alumina. Of the following analyses a. and b. are by Klaproth, from the Lizard ; c. and d. by Svanberg ; e. , by Houghton, from Gue Grease, a., c., and e. are given on the authority of Descloizeaux : STEPHANITE. STILBITE. 97 Silica Magnesia Alumina Peroxide of iroi Lime a. b. c. d. e. 45-00 48-00 46-8 4219 42 "28 24-75 20-50 33'3 30'57 2970 9-25 14-00 8-0 7-67 7'21 l 1-00 1-00 0-4 07 the solution yields a curdy precipitate on addition of common salt or HC1. Cornp. The author is not aware of any analysis of a British specimen, but a specimen from Schemnitz yielded to H. Potash "Water 075 18-00 15-50 ll'O 18-46 18 '92 Ro>e 68*52 per cent, of silver, 0'64 per cent of copper 14 '68 percent of anti- Total . . . 98-75 99-00 100'2 98'80 98'11 mony, and 16 '42 per cent, of sulphur. With silica 50*4 per cent., magnesia 34 "1 per cent., and water 15 '5 per cent, the formula may be written MgSiH 2 or MgSiW 3 + H 2 O or SiOMgo" + OH 2 . In this case the alumina must be regarded as replacing part of the silica. Dr. Frankland gives the formula of steatite as Si 4 O 5 Mgo" 3 , which is, perhaps, a va- riety of talc, since it is anhydrous and contains no alumina. Probably many different minerals have been described as steatite. Loc. Kynance Cove, Mullion, Pedn- boar, Cadgwith, Coverack, and other parts of the Lizard district, in veins, in serpentine ; near Trelowarren, in green- ish-blue veins in olive-green serpentine ; Penmare Point ; " In a tin lode in Carn- yorth Moor, and in small veins in slate to the south of Pendeen Cove;" "Bo- tallack, in a tin and copper lode, with oxide of iron ;" St. Ives ; Cook's Kit- chen (lithomarge ?) St. Cleer, and near the Cheesewring ; Pollaphant ; Clickor Tor, in joints of impure serpentine, &c. It occurs also in Cumberland, Wales, Scotland, Ireland, and many foreign localities. Obs. It is best distinguished from Lithomarge by the reactions for magne- sia obtained by means of the blowpipe, or in humid analysis. It may be distin- guished from Agalmatolite in the same manner, and by its inferior hardness. Stellate. Occurring in the form of a star, as is often seen in specimens of Py- rolusite and other minerals. STEPHANITE. [Brittle Sulphuret of Silver. Black Sulphuret of Silver.] Rhombic; in tabu- lar or short columnar crystals ; or globu- lar, massive, disseminated, or investing ; sometimes drusy ; brittle, or sectile ; fracture imperfect conchoidal to uneven ; lustre metallic ; iron-black ; streak the same; H. 2'5; G. 6 '2-6 '3. B., etc. In matrass a white or yellow- ish sublimate ; on C alone melts to a dark grey bead, and deposits a white in- crustation ; sometimes gives off an ar- senical odour ; with soda or borax RF yields a malleable bead of silver ; de- composed by -warm HNO 3 , leaving oxide of antimony and sulphur undissolved; With 69'7 per cent, of silver, 131 per cent, of antimony, and 17 '2 of sulphur the composition will be Ag 6 SbSi or Loc. Huel Ludcott, recently, with fibrous native silver and beautiful half- inch cube-octahedrons of argentite, in brilliant crystals of 1 lines long. (Davies' Geol. Mag.) STIBIGONITE. [Stibiconise. Stiblite. Antimon-ochre in part.] Amorphous, brittle ; fracture uneven or earthy ; opaque ; dull or glim- mering ; colour yellowish ; streak yel- lowish-white, glimmering; H. 5'5 (?) Greg and Lettsom, and Bristow); G. 5-28. B., etc. In matrass yields water ; on C is readily volatilized, depositing a white coating on the support; with soda is easily reduced to a white brittle me- tallic bead ; soluble in warm HC1. Comp. Hydrated antimonic oxide. With antimony 71 '2 per cent., oxygen 23 '2 per cent,, and water 5 '6 per cent., which is not far from the composition of some foreign specimens, the formula may be written Sb 2 H 2 or Sb 2 O 5 + H 2 O. LOG. "The antimony ochre accom- panying Bleinierite and Jamesonite, at Trevinnock, near Endellion. appears to be this variety." (Greg and Lettsom, p. 372.) Stibine. Stibium. V See Antimonite. Stibnite. t'4.) bibine. \ tibium. \- bibnite. J STILBITE. [Desmin. Foliated Zeolite. Sphsero- stilbite.] Rhombic ; in modified prisms; (Figs. 108, 109), the faces often curved, striated, or rough ; cleavages highly per- fect, parallel to a ; imperfect, parallel to b ; often in groups of imperfect crys- tals, laterally aggregated; also massive; compact, columnar, or radiating ; brit- tle ; fracture uneven ; semi-transparent to translucent ; lustre vitreous, pearly on cleavage planes ; white, grey, yellow, brown, red, &c.; streak white; H. 3 '5-4; G. 2-2-2. B. , etc. In matrass gives off water ; on C fuses with intumescence to a 98 STILPNOSIDEKITE. SULPHIDE. blistered glass or enamel ; -with Co. turns blue ; slowly but completely decomposed by HC1, leaving gelatinous silica. Comp. Hydrated silicate of alumina and lime. The Cornish specimens have not been analysed, but foreign speci- mens yield about 56 per cent, of silica, 15 '9 per cent, of alumina, 8 '6 per cent. of lime, and 19 '5 per cent, of water. "With these proportions the formula may be written Al 2 Ca6Si-l- 7H 2 or Al 2 3Si0 3 + CaSiO 3 + 2H 2 SiO 3 +5H 2 O or Si 6 O 6 Al 2 O iv Cao" + 70H 2 . Loc. The rocks between Botallack and Huel Cock, " crystallized in flat four-sided prisms, with wedge-like sum- mits," with Prehnite and Mesotype (J. Came, Trans. K. G. S. C., vol. II). Found also in Scotland, Ireland, and many foreign localities. Obs. It usually occurs in granitic, basaltic, or highly altered schistose rocks, or in cavities of amygdaloidal rocks ; sometimes, however, in veins or "vugs." Angles. O a = 90 00' r r' = 119 16' ab 90 00 Or 132 00 Ma 132 52 Stilpnosiderite. See Limonite. Stream Tin. See Cassiterite. Streak. The colour of the powder of a mineral, a character of very consider- able value in discrimination. Thus Hematite may be distinguished from Limonite by the redness of its streak ; Wolfram may be readily distinguished from Blende by its much darker streak. This test admits of being tried in cases where the sp. gr. cannot be easily deter- mined, as in imbedded crystals, &c. The colour of the streak is best deter- mined by rubbing the specimen on a slightly roughened plate of white porce- lain, when, if not too hard, some of it will be rubbed off. Very often a scratch with a knife suffices, or rubbing with a file, but the mark made in the mineral the scratch must then be distinguished from the colour of the abraded particles the streak. Striated. Minerals which have small channels on their crystalline surfaces are said to be striated. The striations are usually confined to certain planes, and are often of value in discriminative mineralogy. Thus in quartz the stria- tions are horizontal, or across the prisms ; while in topaz they are vertical, or lengthwise. They are produced by partial and interrupted changes in the crystalline form. Structure. This term relates to the internal characters of minerals. It pro- perly includes cleavage, and the various kinds of fractures produced when miner- als are broken. They are often very characteristic. See page 34, Cleavage ; and page 48, Fracture. Sublimate. A vapour condensed to a solid. "When fragments of Pyrites, or of many other minerals, are heated in a ma- trass, sulphur, &c., rises in vapour, and is condensed on the cool part of the tube, thus affording evidence of its presence. The colours of sublimates, appearance (crystalline or amorphous), and volatility are characters of importance. Sub-phosphate of Alumina. See Wa- vellite. Sulphates. Salts composed of sul- phuric anhydride and a metallic oxide, or sulphuric acid, in which the hydrogen has been replaced by a metal. The sul- phates occurring in the two counties are the following : Anglesite, Johannite, Barytcs, Kalinite, Celestite, Langite, Gypsum, Linarite, Bruchantite, Melanterite, Cyanosite, Woodwardite. Goshirite, Of these the first three are anhydrous, the rest are hydrous. Connellite is a sulphate-chloride. Sulphate of Alumina and Potash. See Kalinite. Sulphate of Barytes. See Barytes. Sulphate of Copper. See Cyanosite, Brochantite, Langite, "Woodwardite. Sulphate of Iron. See Melanterite. Sulphate of Lead. See Anglesite and Linarite. Sulphate of Lime. See Gypsum. Sulphate of Strontia. See Celestite. Sulphate of Uranium. See Johannite. Sulphate of Zinc. See Goslarite. Sulphide. A non-oxidised compound of sulphur and any metal. The chief sulphides occurring in the two counties are : Antimonite, Galena, Argentite, Jamesonite, Berthierite, Marcasite, Bismuthinite, Millerite, Blende, Molybdenite, Bournonite, Pentlandite, Chalcocite, Pyrites, Chalcopyrite, Pyrrhotite, Covellite, Stephanite. Srubescite, All the above are anhydrous. Besides these there are the following sulphan- timonides and sulpharsenides : SULPHIDE OF ANTIMONY. TALC. 99 Cobaltite, Polybasite, Fahlerz, Pyrzrgyrite, Mispickel, Tennantite, These are all anhydrous. Sulphide of Antimony. See Antimo- nite. Sulphide of Bismuth. See Bismuthi- nite. Sulphide of Copper. See Chalcocite and Covellite. Sulphide of Copper and Iron. See Chalcopyrite, Erubescite, and Fahlerz. Sulphide of Iron. See Pyrites, Mar- casite, and Pyrrhotite. Sulphide of Iron and Antimony. See Berthierite. Sulphide of Iron and Nickel. See Pentlandite. Sulphide of Lead. See Galena. Sulphide of Lead, Copper, and Anti- mony. See Bournonite. Sulphide of Lead and Antimony. See Jamesonite. Sulphide of Molybdenum. See Molyb- denite. Sulphide of Nickel. See MiUerite. Sulphide of Silver. See Argentite. Sulphide of Silver and Antimony. See Stephanite. Sulphide of Tin, Copper, and Iron. See Stannite. Sulphide of Zinc. See Blende. SULPHUR. Rhombic ; in modified pyramids, often macled ; some of the planes striated ; also drusy, globular, reniform, stalacti- tic, investing, or massive ; brittle ; frac- ture conchoidal or uneven ; transparent to opaque ; lustre resinous to adaman- tine ; yellow, or sometimes reddish, brownish, greyish ; streak light yellow ; H. 1-5-2-5; G. 2 -0-21. J5., etc. In matrass sublimes in brown- ish-yellow drops ; on C burns away with a blue flame and a strong sulphureous odour ; insoluble in HC1 ; scarcely acted upon by HNO 3 . Comp. The purest specimens almost pure sulphur. Loc. Formerly at Nangiles, in cavi- ties of Pyrites, as a greyish pulverulent deposit (J. Garby, Trans. R. G. S. C., vol. VII., p. 92); Poldice; more recently by Mr. Davis, of the British Museum, and by Mr. Tailing, of Lostwithiel, in minute crystals, in the neighbourhood of Liskeard or Lostwithiel. Obs. Sulphur is often found as a greenish -yellow efflorescence on the ground in Carnou Valley after a long continuance of dry weather. The author saw it in many large patches in the sum- mer of 1869 and also in 1870. Sulphuret. See Sulphide, with which it is synonymous. Swamp Ore, Swampy Iron Ore. See Limonite (Bog Iron Ore). Swimming Quartz. See Quartz (Float- stone). Symbols. See Table of the Elements in Part I. T. Tabular. Crystals which are nearly flat are said to be tabular, whatever the system of crystallization. The term is also used to express a variety of struc ture. Thus minerals which will cleave into plates of a moderate degree of thin- ness only, as Barytes, Wolfram, &c. 5 are said to be tabular. TALC. [Soapstone, in part.. Talc Steatite. Lapis Ollaris.] Hexagonal ; very rarely in six-sided tables, with perfect cleav- age ; sometimes in thin pearly six-sided plates ; more usually massive ; foliated, slaty, granular, earthy, or compact ; sec- tile, thin laminae flexible, but not elas- tic ; semi-transparent to opaque ; lustre pearly or waxy ; light-green, white, red- dish, brownish; streak white, or much paler than colour ; unctuous; H. 1-1 '5 ; G. 2-6-2-8. ., etc. In matrass usually gives off a little water ; on C hardens, but remains infusible ; often glows with an intense light in a strong flame ; sometimes ex- foliates or falls to pieces ; treated with Co turns reddish ; with micro, forms a turbid glass, leaving a siliceous skeleton ; insoluble in HC1 or HNO 3 . Comp. Silicate of magnesia, with a little alumina and a small proportion of water. No analysis of a specimen from Cornwall or Devon is known, but a Scottish specimen yielded to Lychnell, 64'53 per cent, of silica, 27 70 per cent, of magnesia, 6 '85 per cent, of protoxide of iron (a much larger proportion than usual), and no water at all. With silica 69 "3 and alumina 30*7 regarding the oxide of iron as accidental the formula would be 3Si2Mg or 2MgSiO 3 +SiO 3 or Si 3 O 4 Mgo" 2 . Loc. It is said to have occurred at St. Just; it is common at Kynance Cove, and other places in the Lizard dis- trict ; St. Stephens ; Beam Mine ; Stenna Gwynn ; and St. Cleer. Obs. Steatite may, possibly, have been mistaken for Talc in the localities 100 TALLINGITE. TIN PYEITES. above mentioned. Steatite usually con- tains a considerable quantity of water and alumina, by the presence of which it may be readily distinguished. Tallingite. A variety of Atacamite found at Botallack, and analysed by Professor Church (Journ. Chem. Soc. II., III., p. 77). See Atacamite. Taste. A character of very limited application in the discrimination of mi- nerals, but very precise when applicable. Thus, cyanoxite, goslarite, mclanterite, halite, kalinife, &c., may be at once re- cognised by their taste. The first three have what is called a metallic taste ; the others are saline. TAVISTOCKITE. [Soft Wavellite?] Rhombic ? in small stellate aggregations of microscopic acicular crystals ; brittle ; transparent to translucent ; lustre pearly ; white ; H. and G. unknown. B. , etc. In matrass gives off water ; on C incandesces and becomes opaque, tinging the flame greenish ; with Co turns blue ; with borax forms a colour- less bead ; soluble with difficulty in HC1 or HN0 3 . Comp. Hydrated phosphate of alu- mina and lime, as appears from the fol- lowing analysis of a recently-discovered specimen from the neighbourhood of Tavistock by Professor Church (Journ. Chem. Soc., II., III., p. 263, 1865):- Phosphoric anhydride 30 '36 Alumina 22'40 Lime 36 '27 Water 1200 Total 101-03 Loc. Near Tavistock, in cavities on Quartz, with Pyrite, Chalcopyrite, and Churchite. The so-called Wavellite from Stenna Gwynn was probably this miner- al, as it was certainly not the true Wavel- lite. It is described by Mr. Michell as follows : " Soft Wavellite, an assem- blage of minute crystals, attached to tufts of quartz, radiating sometimes like a fine powder of down; colour white" (Man. of Min. Truro, 1825, p. 157). It was accompanied by Fluor, Cassiterite, and Chalcopyrite in granite, while the true Wavellite is on slate. TENNANTITE. Cubic ; in small dodecahedrons, octa- hedrons, tetrahedrons, cubes, &c., usually more or less modified (Figs. 3, 8 to 15, 37, 42, &c.); sometimes macled ; rarely massive j brittle ; fracture uneven, im- perfectly conchoidal, or laminated ; opaque ; lustre metallic ; lead-grey to iron-black ; streak dark reddish-brown ; H. 4; G. 4-3-4-5. B. , etc. In matrass decrepitates and yields a reddish sublimate ; on C burns with a blue flame, deposits a white in- crustation, and melts to a dark brittle magnetic bead or slag, giving off sul- phureous and arsenical odours ; with borax and micro, yields reactions for Cu and Fe : after well roasting yields, with soda, a bead of copper, but not readily ; soluble in HNO> Comp. Sulpharsenide of copper and iron. Of the following analyses a. is by Klaproth, of a specimen from Tresavean ; b. by Kudernatsch, from the same loca- lity ; c. by Phillips, from Cornwall ; d. is the composition of an arsenical Fah- lerz, by Hemming, from Gwennap, in- troduced for comparison : a. b. c. d. Copper 4770 48 '94 45 '32 48 '40 IroQ 975 3-57 9'26 14'20 Arsenic ... 12 '46 19 '10 11 '84 11 '50 Sulphur ... 30-25 27 '76 28 '74 21 "80 Silver trace Silica . 0-08 5 '00 Total... 10016 99'45 95 16 100 "90 With copper 42 6 per cent., iron 13 '2 per cent., arsenic 17 '7 per cent, sulphur 26*4 per cent, the formula may be writ- ten Cu 3 FeAsS 7 or 2(Cu 3 Fe)S4 + As 2 S 5 . With a substance of such variable com- position many other formulae might be made to serve. Loc. Dolcoath ; North Roskear ; Cook's Kitchen ; Tincroft ; Cam Brea ; Huel Jewel ; Huel Unity ; Tresavean ; Trevascus ; East Relistian, &c., but not recently. Obs. It is sometimes regarded as an arsenical Fahlerz. A ngles. o o (Fig. 42) = 70 32' a a = 90 OO 7 oo' 109 28 dd 120 00 &c. Mr. Greg's collection contained speci- mens from Cornwall exhibiting the fol- lowing forms, viz., d ; o d ; ad; m d ; a o d ; o o' d ; a o d n. Tetrahedrite. See Fahlerz. Tetrahedron. A solid four : sided figure. The regular tetrahedron is bounded by four equal equilateral triangles (Fig. 33). Tile Ore. See Cuprite. Tin Hematite. See Cassiterite (Wood- tin). See Cassiterite. Tin Pyrites. See Stannite. TIN STONE. TORBEKNITE. 101 Tin Stone. See Cassiterite. Tin-white Cobalt. See Smaltite. Titanite. See Ilmenite. TITANITE. [Spheue.] Oblique ; in modified pris- matic or tabular crystals, often macled, or imbedded ; sometimes granular, fo- liated, or disseminated ; brittle ; fracture conchoidal or uneven ; translucent to opaque ; lustre resinous, vitreous, or adamantine ; grey, yellow, brown, green, black ; dichroic ; streak greyish ; H. 5-5-5; G. 3-4-3-6. B., etc. In matrass unchanged; on C swells up, or fuses slightly on thin to a ds lark glass ; with borax forms a transparent yellow glass ; soluble, ex- cept silica, in HC1; the solution if boiled with tin-foil becomes violet ; decomposed by H 2 SO4 with deposition of gypsum. Comp. Silicate and titanate of lime. With titanic anhydride = 41 '33, silica 30-45, lime 28-22, which is not far from the composition of some foreign speci- mens, the formula may be written CaSiO 3 + SiO 2 + CaTiO 3 + TiO 2 . LOG. Virtuous Lady Mine, in small yellowish crystals, imbedded in chlorite with anatase. Found also in Scotland, Wales, and Ireland, at many localities, but always rare, and usually in gneiss or syenite. It also occurs at many foreign localities. TOPAZ. Khombic ; in modified prisms, usually striated longitudinally, attached or imbedded (Figs. 148, 149); perfect cleavage parallel to O ; sometimes in druses ; rarely massive, or disseminated, in roundish grains, in veins or water- worn pebbles ; brittle ; fracture uneven or conchoidal ; transparent to translu- cent ; lustre vitreous to pearly ; colour- less, yellow, brownish, bluish, or green- ish ; streak white; H. 8 ; G 3 '4-3 '6; pyro-electric. B . etc. In matrass no change ; on C infusible, or fusible at 4 to a blistered enamel; with borax melts slowly to a clear transparent glass ; with Co turns blue ; with micro, in a matrass yields distinct fluorine reactions ; insoluble in HC1 or HNO 3 ; partly decomposed by H 2 SO 4 , with evolution of HF. Comp. Anhydrous silico-fluoride of alumina. No British specimen has been analysed, but foreign specimens yield about 38 per cent of silica, 56 of alu mina, and 16 of fluorine. All the for- mulse given are exceedingly long, and useless as aids to the memory. Professor 4 . r. Gregor first detected potash in the Cornish topazes (Ann Phil., vol. VIII., p. 276). Loc. St. Michael's Mount, in colour- less or bluish crystals, much like Fig. 148, with lepidolite, tourmaline, cassi- terite, fluor, apatite, &c., in the joints of the granite ; Lamorna Cove, under similar circumstances ; Constantine and Mabe, in small bluish crystals in granite ; Huel Kind, Trevaunance, and Seal Hole Tin Mines, St. Agnes, in slate; St. Kea; St. Austell Hill Mine, in a lode, in gra- nite, with cassiterite, quartz, tourmaline, felspar, &c. It is also said to have been found on Lundy Island. It occurs at a few localities in Scotland and Ireland, but is never plentiful. Very fine speci- mens occur at many foreign localities, especially in Saxony and Brazil. Obs. It may be readily distinguished from quartz and other minerals which somewhat resemble it by its perfect and easily obtained basal cleavage, longitu- dinal striation, and hardness. It mostly occurs associated with other minerals containing fluorine, in granitic or schis- tose rocks. A ngles. M M' = 124' 19' O k = 116 12' MO 90 00 Oi 119 05 Ma 117 50 ki 155 13 Oa 90 00 kk f 130 27 Oe 147 41 IT 86 52 On 136 29 o o' 141 07 Oy 117 47 nn' 87 01 Oo 134 32 TORBERNITE. [Uranite, in part. Chalcolite.] Py- ramidal ; usually in thin tables, more or less modified on the edges and angles (Figs. 74, 75, 76, 84); perfect basal cleav- age (O); sectile ; transparent to translu- cent ; lustre vitreous to adamantine, pearly on cleavage ; green of various shades, sometimes yellowish-green; streak light green; H. 2-2 '5; G. 3-3 '6. B., etc. In matrass gives off water and becomes dark and opaque : on swells slightly and fuses to a dark mass, which, on cooling, presents a crystalline surface ; with soda yields with some difficulty a small bead of copper ; with borax and micro, yields Cu reactions; soluble in HNO 3 , forming a green solu- tion. Comp. Hydrated phosphate of ura- nium and copper. Of the following analyses of Cornish specimens a. is by Phillips ; b. by Berzelius ; c. from Gun- nislake, by Werther; d. by Pisani; 102 TOEBERNITE. TOUEMALINE. e. by Prof Church (Chemical News, XII., 183): a. b. c. d. e. Phosphoric anhydride.. 16'00 15'57 14'34 14'00 13'94 Oxide of ura- nium ...... 60-00 61-39 59-03 59-67 61 "00 Oxide of cop- per ........ 9-00 8-44 8'27 8'50 8'56 Water ...... 14'50 15'65 15 -39 15 '00 1410 Silica ........ 0-49 0"40 Earthy mat.. 0'41 Arsenic anhy- dride ...... 1-96 Lime ........ 0'62 Total.... 99-50 100-45 97 '93 97 '57 100 "24 With oxide of uranium = 61 '2 per cent., oxide of copper = 8 '4 per cent., phos- phoric anhydride 15 '1 per cent., and water 15 '3 per cent, the formula may be written Cu, 2U 2 , PjSH, or CuO, 2U 2 O 3 , P 2 O 5 + 8H 2 Oor2U 2 O 3 , P 2 O 5 + CuH 2 O 2 + 7H 2 0. LOG. Huel Edward, St. Just, formerly, with autunite ; Huel Trenwith ; Provi- dence Mines ; Huel Buller, in dark green crystals ; South Huel Basset, with autu- nite ; South Huel Frances ; Tin croft ; Tolcarne, with autunite ; Huel Gorland ; Huel Unity ; Ting Tang ; Huel Jewell ; St. Agnes ; Stenna G-wynn, in small pale crystals, with fluellite ; St. Stephens ; Huel James Copper and Iron Mine, Withiel, in very fine dark green crystals, in gozzan ; Gunnislake, very fine, form- erly, in large thin aggregated plates, with smoky grey quartz, at about 90 fathoms from the surface. Many years ago very many specimens were raised and sold from this locality. Bedford United Mines, near Tavistock, formerly, in small crystals. It also occurs in Ireland, and in many foreign localities. Obs. It may be distinguished from chalcophyllite by the form of the crys- tals and the absence of arsenic ; from autunite by its green colour and Cu. reactions. J. Garby states that speci- mens of "Chalcolite" were found at " Huel Basset and Huel Buller which were very phosphorescent when first dis- covered, so that after the lights were extinguished many of the crystals might be discovered in situ." (Trans. R. G. S. C., VII. , p. 86.) Angles. OM MM a a Oa Ma Ot 90 90 90 90 135 134 00' 00 00 00 00 50 O s = Oo Or Ou 140 136 111 109 Ov 107 07' 45 45 34 35 The Cornish forms observed are, ac- cording to Greg and Lettsom, e, e O, evO, evOt, rO, rsO, rsOa, rsOt, rvOt, oO, uoO, xoO, MoO, SuO, sOa, MrO, MrOa, MrsOt, MusOl, MusOa. Most of these were in Mr. Greg's collection. Touch. A character of some import- ance in the discrimination of some minerals. Thus Graphite feels unctuous, while Pyrolusite feels harsh. Tough. Not easily broken. Ex. Horn- blende. The term is used in contradis- tinction to brittle. TOURMALINE. [Schorl.] Hexagonal ; in longitudinally striated prisms, usually imbedded, or ining nests or " vugs ;" often acicular and interwoven ; sometimes in distinct crystals, the termination at least like those shewn in Figs. 212, 215, 216; often massive ; columnar, fibrous, par- allel, or divergent ; or compact ; very brittle ; fracture sub-conchoidal or un- even ; semitransparent to opaque ; lustre vitreous, often splendant, sometimes only glimmering ; sometimes white, red, blue, pink, or mottled, but more usually brown, green, or black ; streak white ; H. 7-7-5 (if Zeuxite is a variety the H. is as low as4); G. 2 '9-3 '3; pyro-electric ; frictio-electric. Var. 1. Schorl is the dark coloured and nearly opaque variety, containing a large proportion of iron, which is com- mon -in many of the granites of Devon and Cornwall. 2. Zeuxite is, perhaps, a variety. It occurred in translucent, four-sided green- ish-brown prisms. 3. Kubellite is a red and semitrans- parent variety. 4. Indicolite is blue and semitrans- parent. 5. Peridot is yellow and semitranspa- rent. 6. Achroite is colourless and trans- parent. These last four are all foreign. B., etc. In matrass no change; on C fuses at about 3 to a dark usually mag- netic slag ; with fluor and bisulphate of potash melts and colours the flame green; with borax and micro, the dark varieties usually give reactions for iron ; insoluble in HC1 or HNO 3 ; the powder slowly de- composed by H 2 SO 4 . Comp. Anhydrous silico-borate of alumina and various bases. Of the ac- companying analyses a. and b. were fine black specimens from Bovey Tracey, analysed by Mitscherlisch, and Gmelin ; TOUEMALINE. UMBEE. 103 c. is the analysis of Unity, by Thomson, Silica Boric anhydride... Alumina Peroxide of iron ... Protoxide of iron.. Oxide of manganese Magnesia Lime Soda Potash Phosphoric anhyd. Fluorine "Water and loss .. Zeuxite, from Huel for comparison : b. c. 35-20 33-48 411 35-50 31 -85 a. 37-00 7-66 33-09 9'33 619 26-01 - 1-43 - 2-58 0-70 0-50 0-55 2-46 1-39 2-09 0-65 012 1-49 5-28 Total lOO'OO 97-44 99'08 With silica = 39 '3 per cent., alumina 45 '0 per cent., and protoxide of iron 15 '7 per cent, the formula might be written Fe2AL3Si or FeSiO 3 2Al 2 SiO g or AI S (SiO 3 ) 3 + (A1 2 O 3 + B 2 O 3 ) + FeO. It would, however, tlms become necessary to re- gard part of the alumina as being re- placed by boric anhydride. A general formula for all the tourmalines is some- times given as (3R, R 2 Ba)f Si. Dana gives a very large number of analyses of tourmalines, from many localities. LOG. CORNWALL a. Black or very dark green Tourmaline (Schorl). Fine specimens have occurred on Roscommon Cliffs (Figs. 215, 216), Botallack Mine, the Crowns, Boscaswell Downs, Bos- cawen Cliffs, Cape Cornwall, Pendeen Cove, with fine crystals of felspar, in schorl rock, and many other loca- lities in St. Just ; the Land's End, brownish and radiating; Wicca Cove, near Zennor ; Kosemergy and Morvah United ; near the Logan Kock ; Ding Dong; St. Michael's Mount ; Huel Darlington; Great Work, Breage, in fine dark brownish-green radiating masses ; Constantine ; Mabe ; Trevalgan, St. Ives Consols, and other places in St. Ives ; Providence Mines ; Herland and Relistian, in Gwinear; Huel Druid, Dolcoath, Cook's Kitchen, Cam Brea, Ting Tang, West HuelJewell, and many other localities in Gwennap ; Carclaze, and other localities near St. Austell ; Luxulyan, in porphyry, near the Via- duct ; St. Cleer, in granite ; Kit Hill United, &c. DEVON Very fine black crystals, like Fig. 212, occurred many years ago in a quarry of red granite at Chudleigh ; near Bovey Tracey, associated with fine crys- tals of white and translucent apatite. Good specimens, not distinctly crystal- lized, have occurred near Chagford; Birch Tor Mine, North Bovey ; Bovey Heathfield ; Haytor ; near Okehampton ; Blatchford, near Corn wood ; Holme Lee ; Buckfastleigh ; TJgborough Beacon ; Bowdley, near Ashburton ; generally on the flanks of the granitic mass of Dart- moor ; and Lundy Island. b. Green Tourmaline occurs on the flanks of Cam Marth, and in white gra- nite at Okehampton. c. Achroite (?) occurs at Roscommon Cliffs, St. Just, in "small transparent colourless crystals, "associated with black crystals, like Figs. 215, 216, and with a massive variety, with finely laminated aad radiated structure. d. Zeuxite occurred in the year 1814 at Huel Unity, in small translucent greenish-black crystals, much interlaced. (See PhiUMag., August, 1855.) The foreign localities of the various forms of tourmaline are exceedingly numerous. Obs. Tourmaline may be easily dis- tinguished from substances which some- what resemble it by its specific gravity, longitudinal striations, brittleness, pyro- electricity, and by the form of the crys- tals when distinctly crystallized. Angles. R R = 133 08' a t = 142 26' R'e' 156 34 a a' 120 00 R o 152 40 a b 150 00 Rs 141 30 bb 120 00 Ra 113 26 so 134 02 as 128 30 ee' 154 59 Towanite. See Chalcopyrite. Translucent. See Diaphaneity. Transmitted Light. See Reflected Light. Transparent. See Diaphaneity. Tremolite. See Amphibole. Truncated. A term which is used in the same sense as Modified, which see. Tungstate of Iron. See Wolfram. Tungstate of Lime. See Scheelite. Tungsten. See Scheelite and Wol- fram. Tungstic Acid. } Tungstic Anhydride. > See Wolframite Tungstic Ochre. J U. Umber. See Limonite. Uncleavable Fluor. See Fluor (Chlo- rophane). Uncleavable Manganese Ore. See Psilomelane. Uncleavable Uranium Ore. See Pitch- blende. 104 UNCTUOUS. YINIANITE. Unctuous. Such minerals as feel slip- pery when handled are said to be "unc- tuous." Ex. Graphite, Lithoraarge, Steatite. Uneven. See Fracture. Uranite. See Torbernite and Autu- nite. Uranium. "I Uranium Ochre. V See Pitchblende. Uranium Ore. J Uran Mica. See Autunite and Tor- bernite. V. VALENTIN1TE. [Oxide of Antimony, in part.] Khom- bie ; in prisms, with some faces curved or rough ; longitudinal cleavages, very perfect ; sectile ; fracture not observ- able ; semitraosparent to translucent ; lustre adamantine or pearly ; white, to grey, yellow, brown, or red ; streak white; H. 2'5-3'0 ; G. 5 '5-5 "6. B., etc. In matrass sublimes com- pletely ; on C melts at 1, and deposits a crystalline white incrustation on the support ; if mixed with soda and cyanide of potassium is readily reduced to a grey brittle bead, tinging the flame green ; with borax forms a glass, which is yellow while hot, nearly colourless on cooling, like senarmontite ; soluble in Aqua Be- gia, and re-precipitated on addition of water, if the solution be concentrated. Comp. Anhydrous oxide of antimony like senarmontite. Sb 2 or Sb 2 O 3 , which .is, therefore, dimorphous. Loc. It is said to have occurred in white, fibrous, and radiated masses, with other antimony ores, at Lee, near Cal- lington. It occurs also at several locali- ties in Bohemia, Germany, France, &c. 06s. It is to be distinguished from senarmontite by its crystalline form. Variegated Copper Ore. See Erubes- cite. Variegated Vitreous Copper is a mix- ture of Chalcocite and Chalcopyrite, found in some copper mines. It has the colours of tempered steel. Vesicular. See Cellular. Vitreous. See Lustre. Vitreous Copper Ore. See Chalcocite. Vitreous Silver Ore. See Argentite. VIVIANITE. [Phosphate of Iron. Blue Iron Earth.] Oblique ; in prisms more or less modi- fied (Figs. 168, 169, &c.) ; with perfect clino-diagonal cleavage (b) often acicular, aggregated, or divergent ; also globular, reniform, fibrous, or earthy ; sometimes investing other ores of iron ; sectile, thin plates flexible ; transparent to opaque ; lustre pearly, vitreous, or sub-metallic ; pale green to deep blue ; crystalline or foliated specimens dicbroic, often red- dish or yellowish in some directions, and sometimes much like some micas ; earthy varieties a very pui'e blue colour ; streak bluish white, darkens on exposure, colour of powder liver-brown when dry ; H. 1-5-2 ; G. 2-6-2 7. Var. a. Crystallized Vivianite, often green, sometimes emerald-green and transparent. b. Blue Iron Earth. Soft, earthy, and without lustre ; colour a very beautiful pale blue. It is sometimes nearly white when first obtained. B., etc. In matrass gives off much water ; on C melts at 1 to a grey shining magnetic bead, colouring the flame bluish- green ; with borax and micro, gives Fe reactions ; soluble in HC1 and HNOs. Comp. The following analysis of a specimen from St. Agnes is by Stro- meyer : Phosphoric anhydride 31 "18 Oxide of iron 41 '23 Water 27'48 Total 99-89 Loc. Botallack and Huel Edward, St. Just, formerly, and again at Huel Edward, recently, in fine foliated masses of greenish, reddish, yellowish, and brownish colours, also in acicular crys- tals, and as Blue Iron Earth ; Park- noweth, formerly, compact and earthy ; Huel Gorland ; Huel Jane and Huel Falmouth, in fine flat crystals on pyrites and pentlandite ; Huel Kind, formerly, in the finest crystals ever found, some two inches long and three-quarters of an inch across, on pyrrhotite with chaly- bite ; Huel Betsy and Huel Friendship, near Tavistock. Found also in alluvium near Bristol, and in mud in the Isle of Dogs, London, as well as in several other British and many foreign locali- ties. Obs. The Cornish crystals are not often distinctly terminated. Angles. O M = 117 40' v b = 120 25' Oa 125 47 y y' 154 14 Ov 149 35 ya 167 07 MM' 111 12 br 109 34 Ma 145 36 bz 105 19 Mb 124 24 na 144 20 WAD. WAVELLITE. 105 w. "Wad. A Cumberland name for gra- phite. WAD. [Earthy Manganese. Bog Manganese.] Amorphous ; often reniform, botryoidal, arborescent, pulverulent, or investing; occasionally so full of cavities as to ap- pear frothy ; sometimes with a curved lamellar structure ; sectile or brittle ; fracture earthy ; opaque ; lustre sub- metallic, glimmering, or dull; dark brown or nearly black ; streak dark brown ; scratch shining ; soils the fingers ; H. to 3-0; G. 2-37. B. , etc. In matrass yields much water ; on C infusible ; with borax or micro, gives reactions for Mn ; soluble in warm HC1, giving off Chlorine. Comp. Impure hydrated manganic oxide, with often a proportion of oxide of cobalt, in which case it may be re- garded as passing into asbolane. Some- times a quantity of black oxide of copper is present. The following analysis of a specimen from Upton Pyne is by Turner : Manganic sesquioxide 79 12 Oxygen 8'82 Water 10'66 Boric oxide.... 1'40 Total 10000 LOG. Huel Bucketts ; Pednandrea ; South Tolgus ; Gerrans ; Lifton, near Launceston, in botryoidal masses ; Upton Pyne, in dark brown masses of very low specific gravity. It occurs also in Der- byshire and Scotland; and in Germany, France, and other foreign localities. Warringtonite. See Brochantite. WA VELLITE. [Hydra rgillite.] Rhombic; usually in hemi-spherical or globular masses, with radiated structure ; brittle ; fracture un- even or sub-conchoidal ; translucent ; lustre pearly, a ilky, or vitreous ; yellow- ish, greyish, greenish, bluish ; sometimes a brown or black tarnish ; streak white ; H. 3*5-4 ; G. 2 "3-2 '4. B., etc. In matrass yields water and turns white ; on C fuses with intumes- cence to a white opaque mass, tinging the flame bluish-green ; with Co turns blue ; soluble in HC1, HNO 3 and KHO ; with micro, yields traces of fluorine. Comp. Hydrated phosphate of alu- mina, as appears from the following analyses of specimens from Barnstaple. a, and b. by Fuchs, c. by Berzelius : Phosphoric anhyd... 3512 34 *84 33 '40 Alumina 37'20 3716 35 "35 Fluorine . 2'06 Peroxides of iron & manganese 1-25 Lime _ __ Q'50 Water 28'00 28 "00 26 "80 Total 100-32 lOO'OO 99'36 With phosphoric anhydride 35 1 per cent., alumina = 33 '2 per cent., and water = 26 '7 per cent, the formula may be written 3A1 2 2P 2 + 12H 2 or 3AL,O,2P, 5 + 12H 2 or P 4 0(A1 2 6 ) 3 120H 2 . The following analyses, d. from Barn- staple, by Klaproth ; e., ditto, by Davy; f., Cornwall, by Gregor, are given in Jameson's Mineralogy, I., p. 334, 1816: (Phosphate) alumina 71 '50 70 "0 58 '70 Oxide of iron 0'50 019 Lime 1-4 0-37 Silica 612 Water 28'00 26'2 3075 2-4 3-87 Total lOO'OO 100.0 lOO'OO Loc. It is said to have been found at Beam Mine ; at StennaGwynn, on decom- posing granite, in greyish-green radiated masses, about as large as peas ; and at Kit Hill, on elvan. The best known lo- cality is Filleigh, near South Molton, near Barnstaple, on clay-slate. Obs. " It was first discovered about the year 1785, by Mr. I. Hill, of Tavistock, and, being mistaken for a pure hydrate of alumina, it was called Hydrargillite, until Dr. Wavell, of Barnstaple, about thirty years afterwards, shewed that phosphoric acid was present in large quantities, and the substance, which thus constituted a new species, was named Wavellite. The usual form of this mineral is that of a hemisphere, varying in size from ene-twentieth of an inch to one inch in diameter. When broken, the internal structure is found to be composed of acicular crystals, finely radiated. Wavellite is also found frequently filling small crevices in the slate rock, and not having had sufficient space to crystallize in its primary form, it has accommodated itself to the breadth of the fissure, spreading out and covering the surfaces of the rock with a profusion of radiated circles, which are sometimes two inches in diameter, and vary in thickness from one-eighth to a film not more than l-200th of an inch " (Trans. Dev. Assoc., vol. II., pt. II., p. 341 1868). Wavellite has also occurred in 106 WHEEL OEE. WOLFRAM. Northumberland, Scotland, Ireland, and many foreign localities. Wheel Ore. See Bournonite. "White Antimony Ore. See Senarmon- tite and Valentinite. White Arsenic. See Arsenolite. White Cobalt. See Cobaltite and Smaltite. White Lead Ore. ) rpr . 18site White Lead Spar, f b lte> White Mundic. See Leucopyrite, Mar- casite, and Mispickel. White Iron Pyrites, White Sulphuret of Iron. See Marcasite. White Vitriol. See Goslarite. Wild Lead. An old term for Blende. WITTIGHENITE. Rhombic, in small, nearly square prisms ; more usually in imperfect ag- gregations of acicular crystals with one perfect vertical cleavage ; or massive, with coarse columnar cleavage ; also dis- seminated ; brittle ; opaque ; lustre me- tallic ; tin-white to steel-grey ; readily tarnished by exposure to light or air streak black ; H. 3'5 ; G. 4 '3-5. S., etc. In matrass yields a light sub- limate ; in open tube gives a white sub- limate and a strong sulphureous odour ; on C fuses at 1, giving off brilliant sparks and coating the support dark brownish- yellow ; with soda yields a globule of copper ; soluble in HC1 or HNO 3 ; the solution yields a white precipitate when largely diluted with water. Comp. Anhydrous sulphide of bis- muth and copper. A specimen from Baden yielded to Klaproth 47 '24 per cent, of bismuth, 34 '66 per cent, of cop- per, and 12 '58 per cent, of sulphur. Loc. The " Cupreous Bismuth," formerly reported from Botallack, Le- vant, and Huel Buller may, possibly, have been this species. That from Huel Buller occurred " in perfect hexagonal prisms, tin-white and lustrous when first raised, but soon becomes dull and tar- nished." (Garby, Trans. R. G. S. C.) WOLFRAM. [Tungstate of Iron.] Rhombic ; some- times in crystals, like Figs. 118, 119, with perfect and easily obtained cleav- age parallel to M ; less perfect par- allel to b u ; crystals are usually im- bedded, and often striated, curved, or macled ; sometimes in acicular crystals; often massive ; brittle, fracture uneven ; opaque ; lustre metallic or sub-metallic, brilliant on freshly exposed surfaces ; dark greyish or brownish-black, not un- frequently with an iridescent tarnish ; streak dark reddish -brown; H. 5-5 "5 ; G. 7-7 '6 ; some specimens feebly magne- tic. J5., etc. In matrass decrepitates strongly and breaks up into thin flakes, but is otherwise unchanged ; on C fuses at 4 to a black magnetic mass, sometimes crystalline on the surface ; fused with soda forms a green mass ; with borax and micro, gives Fe and Mn reactions ; slowly decomposed by warm HC1, more readily with Aqua Regia, with deposition of yellow tungstic anhydride. Csmp. Anhydrous tungstate of iron, with some manganese, as appears from the following analysis of a specimen from Godolphin Bal by Kerndt, the specific gravity of which was 7 '21 : Tungstic anhydride 75 '92 Oxide of iron 19'35 Oxide of manganese 4'73 Total lOO'OO With tungstic anhydride = 7710 per cent., oxide of iron = 18'27 per cent., and oxide of manganese = 4 '63 per cent. the formula might be written 4Fe, Mn5W or (4-5 Fe 1-5 Mn)WO 4 . Loc. St. Michael's Mount, with cas- siterite, fluor, topaz, &c. ; Godolphin Bal, Breage ; Huel Prospidnick, Sithney ; Herland; Dolcoath; Cook's Kitchen; Tincrof t ; Cam Brea ; East Pool, in aci- cular crystals, and in large macles, with striated or curved surfaces, imbedded in quartz or chlorophane ; Pednandrea, im- bedded in chlorite, both massive and crystalline ; Huel Fanny, in prisms (Figs. 245, 246); Huel Harmony ; Pol- dice, massive and acicular, in quartz and chlorite; Cligga; Stenna Gwynn, crys- tallized ; Beam Mine ; Gobnbarrow ; Gunnislake ; Drake Walls, fibro-lamel- lar and massive ; Kit Hill ; &c. Wol- fram has also been found at Huel Friend- ship and several other mines near Tavis- tock. 06s. The Cornish specimens, although often very fine and pure, are seldom dis- tinctly crystallized, they are frequently imbedded in quartz, in large cleav- able masses or imperfect tabular crystals. Wolfram may be distinguished from Cas- siterite by its perfect cleavage, inferior hardness, and dark streak ; from Blende and Schorl by the colour of its streak, and by its sp. gr. Angles. M M = 101 05' b a = 90 00* Mt 110 46 bt 117 20 Mb 140 32 uu 99 12 The plane M is striated vertically. WOLEKAMITE. ZIPPJEITE. 107 WOLFRAMITE. [Wolframine. Wolfram Ochre.] Cubic? in earthy or pulverulent masses, invest- ing wolfram ; opaque ; dull ; yellow, greenish, or brownish ; H, 0-1. B., etc. In matrass gives off water and turns black ; on C infusible ; with borax forms a colourless bead, unlike the other minerals with which it may be confound- ed (Yellow Ochre, Zippseite, &c.); inso- luble in HC1; soluble in caustic alkalies. Comp. Hydrated (?) oxide of Tungs- ten, or, more probably, tungstic anhy- dride which has absorbed some moisture from the air. LOG. East Pool, Poldice, Drakewalls, and Huel Friendship, investing wol- fram. Found also in Cumberland, France, and the United States. Wood Arseniate of Copper. See Oli- venite. Wood Iron Ore. See Limonite. Wood Tin. See Cassiterite. Woodwardite, An impure Langite, or mixture of Langite and Allophane. It occurs in minute concretions of a tur- quoise-blue or greenish-blue colour, and is translucent or almost transparent ; sp. gr. 2*38. It is soluble, almost com- pletely, in dilute HC1 or HNO 3 . Of the following analyses the first, a., is by Professor Church; b., c. are by War- rington ; d. is a very similar mineral, analysed by Pisani. In a., b., c. there were traces of silica, lime, magnesia, and phosphoric anhydride : - a. b. c. d. Sulphuric anhy. 13'95 13 '04 12'54 11 '7 Oxide of copper 48 "34 48'67 4680 46'8 Alumina 17 '97 18 '64 17 '93 13 '4 Silica 1-2 Water 18 '48 19 '65 22 "73 26 '9 Total 98-74 100 '00 100 '00 100 '0 Another mineral, much resembling Woodwardite, yielded to Pisani : Sulphuric anhydride 4 '7 Oxide ot copper 17 '4 Alumina 33'8 Silica 6'7 Water 38'7 Total 101-3 M. F. Pisani therefore regards both Woodwardite and this new mineral as mixtures, in very different proportions, of Langite and Allophane. A specimen of a similar Cornish mineral, examined recently by Professor Maskelyne and Dr. Flight, had the com- position given below. " It occurs in very thin crusts, of various shades of yellow and green, the surface exhibiting a wavy appearance. Though the outer surface is occasionally somewhat compact, the mass is loose, and some of the layers pul- verulent, a. shews the composition of the inner layer, and b. that of the outer crust": Ox. of copper. Alumina Lime .... Magnesia Soda .... Sulph. anhyc Silica Oarb. anhyd. Water: Lost a ord. temp. . 100 . . . 1200-260" . over 260<> . a. 24-561 23-063 0-749 6-775 b. 10-255 27-250 1-403 6-183 0-640 2-433 7-538 0-528 15-390 10-413 ) 7-333 | 5-392 6-167 38-528 23-864 Total .... 100-451 100-199 For further information see Church, Chem. News, XIII., 85, 113, 1866, and Journ. Chem. Soc., II., iv., 130; Pisani, Phil. Mag., April, 1868, p. 320 ; Maske- lyne and Flight, Journ. Chem. Soc., Jan., 1871, p. 1. See also Langite. Y. Yellow Copper Ore. See Chalcopyrite. Yellow Ochre. See Limonite. Yellow Oxide of Tungsten. See Wol- framite. Yellow Oxide of Uranium. See Zip- Zeuxite. See Tourmaline. gfij Zinc Spar. See Calamine. Zinc Vitriol. See Goslarite. ZIPP&ITE. [Uranochre, &c.] Amorphous : earthy or pulverulent ; opaque ; dull ; lemon, or sulphur-yellow, or sometimes brown- sh-red; H. 0-1. ., etc. In matrass yields water and darkens in colour ; on C turns green but does not fuse ; with borax and micro, yields uranium reactions ; soluble in ENO 3 , forming a yellow solution. Comp. Oxide of uranium, probably lydrated. Loc. Huel Edward, St. Just; St. 108 ZIPP^ITE. ZIPP^ITE. Michael's Mount, coating mica on quart- zose rock. "A specimen given to Mr. Greg by Mr. Nuttall appears to be slightly crystallized in plates, as if the result of the decomposition of uranite ' " (Greg and Lettsom, p. 382). Formerly in small green earthy globules, on pitchblende, at Huel Buller ; Carharrack ; more re- cently at Pednandrea and Clyjah Mine ; and at Goonbarrow (?); "Wlthiel Iron Mine, Kestormel. Formerly in consider- able abundance at a tin mine in Calling- ton. Zippseite has also been found in several foreign localities. THE END. TRURO : PRINTED BY HEARD AND SONS, BOSCAWEN-STREET. ADDENDA. ANTHKACITE. The Author has found thin layers in the joints of the rocks at Pednandrea Mine, andatRoscrow United Mines, Ponsanooth. AXINITE. Additional localities to those on p. 12, Pt. II : Old Treburgett, St. Teath ; and Ivy Tor, Copper Hill Mine, Huel Forest, Fursdon Manor Mine, Meldon Quarry all in Devon. See Trans. Dev. Assoc., vol. II., Pt. II. , p. 344, 1868. EL.EOLITB. (Nepheline) Hexagonal ; Brittle ; fracture conchoidal or uneven ; transparent to semi-translucent; lustre vitreous to resinous; colourless, grey, red, brown, or bluish green ; streak white, H. 5-56-0, G. 2 '58 2 '64. .B., etc. Infusible or fusible with diffi- culty ; with Co. turns blue ; translucent splinters become opaque if treated with HNO 3 , Powder decomposed by HC1. Comp. Anhydrous Silicate of Soda, Potash, and Lime. Loc. The Wolf Rock, nine miles S.E. of the Land's End with glassy Felspar and green Hornblende in yellowish grey masses of imperfect Crystals. "The greater part of the mass of the rock is seen to consist of 'Nephelinp,' the 1 " Crystals varying in size' from the - 1 " 150 to across." S. Allport, F.G.S., in 310 Geol. Mag., June, 1871. EPIDOTE. A specimen from Old Tre- burgett Mine, St. Teath, associated with Axinite, is in the Museum of the Royal Institution of Cornwall. PITTICITE. The following is an an- alysis of a specimen from Redruth (Dol- coath?) by Professor A. H. Church, M.A.:- " Carefully selected homogeneous por- tions of a fine specimen of this mineral from Cornwall were submitted to analy- sis, after having remained a year or more in my cabinet. They evidently still contained a considerable amount of hygroscopic water. Water lost at 100 C 876 lost at 175 7-53 retained at 175 8'63 Ferric oxide..., 32'54 Arsenic pentoxide 33'99 Phosphorus pentoxide 1"27 Sulphur trioxide 7'28 100-00 Regarding the water lost at 100 as non-essential or accidental, we may re- calculate the above numbers as follows : Water 17'71 Ferric oxide 35'67 Arsenic pentoxide 37 '25 Phosphorus pentoxide 1 '39 Sulphur trioxide 7'98 lOO'OO I fear that these numbers throw no fresh light upon the constitution of this very variable mineral, and that no satis- factory formula can be deduced from them. One peculiarity of the Cornish specimens consists in the high proportion of arsenic pentoxide which they contain, a proportion which is greater than that in this mineral as derived from any other recorded locality. But, on the other hand, the Cornish Pitticite shows a smaller quantity of ferric oxide than other analysed specimens. It does not appear that phosphorus pentoxide has been previously detected in this mineral. I ought to add that the Cornish mineral was straw to ochre-yellow in colour, subreniform and massive in form, and in great part opaque. The softest, palest, and most homogeneous portions were selected in preparing the sample for analysis. It is not improbable that the darker and less opaque portions would have shown a higher percentage of iron. ORTHOCLASE. The following analysis, by Professor Church (who has favoured the author by communicating it), is of ADDENDA. an Orthoclase from a quarry near Roche, where it occurs as a rock, in large sub- opaque white masses, with thin veins of wuite Quartz and white Mica. Its specific gravity is 2 '56. Silica 6370 Alumina 1976 Ferric oxide '71 Lime trace. Potash 13-61 Soda .. 2-26 100-04 SILVER. The following is an analysis of a specimen from Huel Ludcott, by Professor Church. Sp. gr. 10 '26. Silver 97-86 Chloride of Silver '71 Gold and Antimony Iron *15 Metals precipitable by H 2 S '10 Loss "97 100-00 PSEUDOMORPHS. A fine specimen of Calcedony in cubes probably Pseudo- morphous after Fluor is in the Museum of the Royal Institution of Cornwall. It is believed to be from Beeralston. HEMATITE occurs in irregular nodules in brownish red clay near Totnes, Devon. Plata 1. PLATE I. CUBICAL SYSTEM. Fig. 1. OCTAHEDRON. Cuprite, Fluor. 2. CUBE. Pyrites, Cuprite, Fluor. 3. KHOMBIC-DODECAHEDRON. Garnet, Cuprite. 4. TRIAKIS-OCTAHEDRON. Pyrites, Galena. 5. DELTAHEDRON. Garnet, Argentite, Analcite. 6. HEXAKIS-OCTAHEDRON. Fluor. 7. TETRAKIS-HEXAHEDRON (FOUR-FACED CUBE.) Fluor, Cuprite. 8. Kerate, Argentite, Cobaltite, Fluor, Galena. 9. Kerate, Argentite, Fluor, Galena. 10. Fluor, Blende, Galena, Silver. 11. Galena, Cuprite, Silver. 12. Galena, Cuprite. 13. Galena, Cuprite. 14. Galena, Cuprite. 15. Argentite, Cuprite. 16. Fluor, Cuprite, Pyrites. 17. Fluor. 18. Fluor, Smaltite. 19. Argentite, Analcite. 20. Argentite. 21. Fluor. 22. Fluor. 23. Fluor. 24. Fluor', Cuprite. 25. Garnet. 26. Garnet. 27. Fluor. 28. Fluor. PLATE II. CUBICAL SYSTEM (Cont.) Fig. 29. Galena, Fluor. 30. Fluor. 31. Fluor, Garnet. 32. Pyrites, Fluor. 33. TETRAHEDRON. Fahlerz. 34. DELTOID-DODECAHEDRON. Fahlerz. 35. TRIGONAL-DODECAHEDRON. Blende, Fahlerz. 36. Diamond. 37. Blende, Tennantite. 38. Fahlerz. 39. Blende, Fahlerz. 40. Fahlerz. 41. Fahlerz. 42. Blende, Fahlerz, Tennantite. 43. PENTAGONAL-DODECAHEDRON. Pyrites, Cobaltite. 44. Pyrites, Cobaltite. 45. Pyrites, Cobaltite (very rarely.) 46. Pyrites, Cobaltite. 47. Pyrites. 48. Pyrites, Cobaltite. 49. Pharmacosiderite. 50. Pyrites, Pharmacosiderite. 51. Pharmacosiderite. 52. Pyrites, Blende. 53. Fluor. late 11. Plate #/. PLATE III. CUBICAL SYSTEM ( Cont.) Fig. ^' | Illustrations of Macles. (See page 65) 55. Fluor. (Macled Octahedrons.) 56. Macled Octahedrons, Magnetite. 57. Macled Cube-Octahedrons. 58. Pyrites, Erubescite (Made.) 59. Copper. 60. Copper. PYRAMIDAL SYSTEM. Fig. 61. Cassiterite. 62. Cassiterite. 63. Cassiterite. 64. Cassiterite. 65. Cassiterite. 66. Cassiterite. 67. Cassiterite. 68. Cassiterite (Macled.) 69. Cassiterite (Macled.) 70. Cassiterite (Macled.) 71. Cassiterite (Macled.) 72. Anatase. 73. Anatase. 74. Torbernite. 75. Torbernite. 76. Torbernite. 77. Cassiterite (Macled.) 78. Cromfordite. PLATE IV. PYRAMIDAL SYSTEM (Cont.) Fig. 79. Chalcopyrite. 80. Chalcopyrite. 81. Chalcopyrite. 82. Chalcopyrite. 83. Chalcopyrite. 84. Torbernite, Chalcopyrite (Macled.) 85. Chalcopyrite (Macled.) 86. Scheelite. 87. Scheelite. 88. Scheelite. KHOMBIC SYSTEM Fig. 89. Fluellite. 90. Mispickel. 91. Mispickel. 92. Mispickel. 93. Mispickel. 94. Andalusite. 95. Andalusite. 96. Prehnite. 97. Antimonite. 98. Bismuthinite. 99. Bismuthinite, Pla^V. 102 120 PLATE V. RHOMBIC SYSTEM (Cont. ) Fig. 100. Chalcocite. 101. Chalcocite. 102. Chalcocite. 103. Chalcocite (Macled.) 104. Chalcocite (Macled.) 105. Chalcocite. 106. Chalcocite (Macled.) 107. Chalcocite (Macled.) 108. Stilbite. 109. Stilbite. 110. Manganite. 111. Finite. 112. Natrolite. 113. Natrolite. 114. Wavellite. 115. Leucopyrite, Staurolite. 116. Staurolite (Macled.) 117. Staurolite (Macled.) 118. Wolfram. 119. Wolfram. 120. Bournonite. 121. Bournonite (Macled.) 122. Bournonite, Antimonite. 123. Bournonite. PLATE VI. RHOMBIC SYSTEM (C