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TREATISE ON GEMS, 
 
 IN REFERENCE,TO THEIR 
 
 PRACTICAL AND SCIENTIFIC VALUE; 
 
 A USEFUL GUIDE FOR THE JEWELLER, AMATEUR, ARTIST, LAPIDARY, 
 MINERALOGIST, AND CHEMIST. ACCOMPANIED BY A DE¬ 
 SCRIPTION OF THE MOST INTERESTING AMERICAN 
 GEMS, AND ORNAMENTAL AND ARCH¬ 
 ITECTURAL MATERIALS. 
 
 BY DR. LEWIS F E U C H T W AN G E R, 
 
 CHEMIST AND MINERALOGIST ; MEMBER OF THE NEW YORK LY'CEUM OF NATURAL HISTORY, AND OF THE 
 MINERALOGICAL SOCIETIES OF JENA, ALTENBURG, ETC. ETC. ETC. 
 
 NEW-YORK: 
 
 PRINTED BY A. HANFORD. 
 
 1838 . 
 
Entered according to Act of Congress, in the year 1838, by 
 LEWIS FEUCHTWANGER, 
 
 the Clerks office of the District Court of the Southern District of New York. 
 
I 
 
 Columbia College, New York, 
 26 th March, 1838. 
 
 Sir : 
 
 I have, at your request, perused the manuscript of your 
 Treatise on the Gems. It gives me great pleasure to be able to bear 
 my testimony to the care and labour with which this treatise has been 
 compiled. The work is one which may be usefully employed by 
 teachers of Mineralogy, and particularly in its useful applications. 
 To the practical man it cannot fail to be of great value, from its 
 opening sources of information which, in this country, are as yet 
 confined to but few persons, and from the reputation of the authori¬ 
 ties whence you have drawn your facts. It is, however, in reference 
 to the native minerals and rocks of the United States, that I conceive 
 your treatise to be most likely to be eminently useful. I observe that 
 you have collated the descriptions and localities of American speci¬ 
 mens, which are now to be sought in scientific periodicals, or in the 
 transactions of learned societies. For such searches practical men 
 have not the opportunities, and scientific men, although well aware of 
 the value of our native treasures, are rarely so circumstanced as to be 
 able to render them objects of commercial speculation. This part of 
 your task has been laboriously and faithfully accomplished. 
 
 I am aware that you have experienced a difficulty in being com¬ 
 pelled to write in a language which to you is foreign. On this head, 
 however, you need not feel discouraged. The language of science is 
 universal; and as I have found no difficulty in understanding every 
 portion of your manuscript, I do not doubt that it will be equally clear 
 and intelligible to your readers, when it shall appear in a printed 
 form. 
 
 JAMES RENWICK. 
 
 Dr. Lewis Feuchtwanger. 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
PREFACE. 
 
 Among the many publications of the present day on the various 
 subjects of Natural History, a practical work on mineralogy, as 
 applied to the Arts, has been much needed in the English language. 
 Of this general subject the history of the Gems, in reference to their 
 mineralogical, chemical, and physical characters, and with a view to 
 serve as a guide to the lapidary, the jeweller, and the amateur, is one 
 of the most important branches. 
 
 The author of the following Treatise has, at the solicitation of his 
 numerous friends, consented to fill with his feeble means that vacancy 
 in our literature. Should he therefore have been so successful as to 
 realize their wishes, and to contribute in guarding against deception 
 and ignorance, and in pointing out those theoretical and practical 
 cautions to be observed in the treatment and purchase of Gems, he 
 would feel satisfied that his humble and imperfect efforts are amply 
 rewarded. He has considered the Gems in their most extended sense, 
 and not treated of the mineral productions generally called by that 
 name alone, but has included the Corals, Pearls, and such Rocks as 
 promise to prove ornamental and useful to architecture. He has drawn 
 the attention of the reader to those specific characters which distin¬ 
 guish the true Gems from all other minerals and false stones, the last 
 of which are now in such general use, and are palmed upon the igno¬ 
 rant as precious gems, which in truth are remarkably good imitations, 
 and often require a practised eye to distinguish the false from the 
 true. The former are now worn by all classes, either from ignorance 
 or from the more moderate price at which they can be afforded, and 
 often present nearly the same appearance as real Gems. In order to 
 encourage the artist in the manufacture of those pastes, the author 
 has described the mode of manufacturing them, according to the best 
 information, and from his own experience. 
 
vi. 
 
 PREFACE. 
 
 The author has been very particular in describing all the localities 
 of the various Gems and mineral productions suitable for ornamental 
 purposes, and particularly those of this country, upon which the 
 unbounded blessings of Providence have been spread in the most 
 liberal manner, in order to awaken the mind of the young observer 
 to those rich treasures of Nature which are yet principally hidden 
 beneath the surface of the earth, or which may be left for his future 
 investigation. It is, however, not at all surprising that those rich 
 natural productions with which the American soil abounds, are not 
 yet sufficiently known, or even appreciated, because neither the 
 naturalist nor the student has, in this country, the opportunity of 
 examining cabinets of specimens of these rich treasures. 
 
 It was the author’s intention to accompany this work with plates 
 in illustration of the lapidary’s wheels and tools, as well as of the 
 forms in which all the Gems and minerals originally crystallize. He 
 likewise proposed to prepare coloured prints, representing all the colours 
 of the Gems, such as have been given by Mr. Mawe, in his Treatise 
 on Diamonds and Precious Stones, printed in London in 1813. He 
 would at the same time have extended this work to nearly double its 
 present volume. He has, however, deferred this task to a future 
 occasion, when, after this first essay will have received the sanction 
 of an enlightened public, he may feel encouraged to issue another 
 edition. In the arrangement of the following Treatise, the author 
 has followed the plan of a small work, published in 1832, by Dr. 
 Blum, in Germany ; but he has drawn other references from the 
 following works:— 
 
 Hauy des Pierres Precieuses, 
 
 Braid Mineralogie Appliquee aux Arts, 
 
 Dumas Chemie Appliquee aux Arts, 1821, 
 
 Hitchcock’s Report on the Geology of the State of Massa¬ 
 chusetts, 
 
 Comstock’s Mineralogy, 
 
 Leuch’s Waarenkunde, 
 
 Sillimann’s Journal. 
 
TREATISE ON GEMS. 
 
 PART I. 
 
 INTRODUCTION. 
 
 § I. NATURAL HISTORY. 
 
 All the phenomena of nature which exhibit themselves to our 
 senses are of two kinds: those comprised in a space, or which may 
 be discriminated by our external senses, such as the animal, plant, 
 &c.; or those which do not possess a form, and are only comprehended 
 by the inner senses, such as doubt, belief, &c.: the latter belong to 
 psychology, and the former to physiology, or what we may call phy¬ 
 sics in a more extended term. Physics are then divided in natural 
 philosophy and natural history; this, again, is divided in the percep¬ 
 tion and treatment of organic bodies, such as zoology and botany, 
 and that of inorganic bodies, such as mineralogy. 
 
 § II. DIVISIONS OF MINERALOGY. 
 
 The crust of the globe we inhabit consists of inorganic bodies: 
 minerals in their mechanical, simple, solid, or liquid condition; and 
 mineralogy, in its nearest sense, treats and considers minerals by 
 their individual properties, which refer to form, quality, and material; 
 and this part of the science is generally called oryctognosy: whereas 
 that part of mineralogy which treats of minerals that stand in con¬ 
 stant relation to each other, in regard to their series, or geographical 
 distances of their layers, is called geology. That part of mineralogy 
 which applies minerals to the different arts and other purposes of life 
 is called economical, or mineralogy applied to arts. 
 
 § III. PRECIOUS STONES OR GEMS. 
 
 Precious stones or gems are such minerals as, either from their 
 beauty or other valuable properties, have become the subject of the 
 arts or trade, and are used as ornaments or employed by jewellers. 
 In order to appreciate more fully such minerals as may possess supe¬ 
 rior virtue, it is our present object to consider them in reference to 
 their scientific and practical value. 
 
 B 
 
10 
 
 TREATISE ON GEMS. 
 
 § IV. DIVISION OP GEMS. 
 
 Gems are generally classed as follows: 1st, real gems, or jewels; 
 and, 2nd, in semi, or also precious stones. The first comprise such 
 minerals as combine, within a small space, either vivid or soft and 
 agreeable colours, with a high degree of lustre, usually termed fire, as 
 well as hardness; whereas the second possess these characters in a less 
 degree, and occur often semi-transparent or translucent, and in larger 
 formless masses. It is, however, impossible to draw a strict line 
 between both, as the conventional value put upon one or the other, 
 also affects their character; for very often some, which generally are 
 considered as belonging to the second class, may be valued, for their 
 peculiar properties, much higher than some of the first class. 
 
 Those species of minerals which are generally considered real 
 gems are—- 
 
 Diamond, 
 
 Sapphire, 
 
 Chrysoberyl, 
 
 Spinelle, 
 
 Emerald, 
 
 Beryl, 
 
 Topaz, 
 
 Zircon, 
 
 Garnet, 
 
 Tourmaline, 
 
 Ilubellite, 
 
 Essonite, 
 
 Cordierite, 
 
 Jolite, 
 
 Quartz, 
 
 Chrysolite. 
 
 Tire rest are considered as semi-precious stones. There is another 
 division, arranged according to the hardness of the different species. 
 This property will be considered under its proper head. 
 
 § V. GENERAL DISTINGUISHING CHARACTER OF MINERALS. 
 
 In order to distinguish the crude and polished precious stones by 
 their distinctive characters, it is necessary to describe the minerals 
 more particularly, according to their properties and other peculiarities, 
 which will now be defined more fully. 
 
 § VI. FORM. 
 
 All minerals which are distinguished by the form which they 
 assume within the planes they are included in, are called crystals; 
 and such regular individual forms, are said to be crystallized. On the 
 other hand, such minerals as have not acquired such perfect form, 
 and which appear to us more irregular, are not crystallized, and are 
 said to be amorphous. 
 
 Crystalography is a highly important character to a practical 
 relation of the crystallized form of minerals; for as these forms or 
 
TREATISE ON GEMS. 
 
 11 
 
 modifications are mostly peculiar to each species, one mineral may 
 often, with certainty, be distinguished from another by the know¬ 
 ledge of the difference between the forms of their crystals. The 
 
 great variety of forms under which the crystals of different sub¬ 
 
 stances appear, may all be reduced to a few fundamental or primitive 
 forms, which are— 
 
 F'g- !• 1st. The Parallelopiped, which includes the cube, 
 four-sided prism, rhomb, or any other figure having six 
 -■v. /''I faces, the two opposite ones being parallel with each 
 
 | y/ other. When its angles are equal in every direction, and 
 
 the size of its planes alike, it is the Cube. When the 
 same figure is extended, so as to make the length greater than the 
 breadth, it becomes a four-sided Prism; and when the angles are 
 oblique, that is, alternately acute and obtuse, it is a Rhomb. 
 
 Fig. 2. 
 
 2d. The Octahedron , which has eight triangular 
 faces, four of which meet at points opposite to each 
 other, and has the appearance of two four-sided pyra¬ 
 mids, joined base to base. 
 
 Fig. 3. 
 
 3d. The regular Tetrahedron , bounded by four 
 oblique planes, having four points or angles, and six 
 edges. 
 
 Fig. 4. 
 
 4th. The regular Hexahedral Prism. A solid con¬ 
 tained by eight planes ; namely, six rectangular, a hexa¬ 
 gon, and a six-sided prism, bounded by a terminal plane 
 at each end. 
 
 Fig. 5. 
 
 5th. The Dodecahedron , with rhombic faces. A 
 solid, containing twelve rhombic planes, all similar to 
 each other. 
 
 Fig. 6. 6th. The Dodecahedron , with triangular faces. 
 
 Twelve triangular planes, exhibiting two six-sided pyra- 
 7 \\ mids, joined base to base. These forms are the basis of 
 / many species of minerals, which may yet entirely differ in 
 
 s\ // composition from each other; and although their external 
 appearance may differ from those forms, proper to some 
 
12 
 
 TREATISE ON GEMS. 
 
 minerals, yet each primitive form will always be found to exist under 
 precisely the same angles. 
 
 There are, besides, a vast number of forms under which minerals 
 appear in nature; but the object of the present essay is only to refer 
 to mineralogy as to the most important point bearing upon precious 
 stones: and we will describe, therefore, the crystallization of the 
 different minerals under their proper heads, when treating of the 
 individual minerals used as gems. The non-crystallized minerals 
 exhibit in their external appearance either— 
 
 1 st, A resemblance to certain natural or artificial products; such 
 as a tree, a globe, wire, reniform, knotty ; or they appear in particular 
 forms, unlike other substances, such as a compact, sprinkled, or gran¬ 
 ular; and are divided then into those which have a free formation; or, 
 
 2d, An interrupted formation. Under the first we recognise globu¬ 
 lar, clustered, reniform, dentiform, arborescent, capillary, foliated, 
 stalactiform and prongy. To the second we consider as belonging the 
 pseudo-morphous crystal, the amygdaloid, spectre, form of petrifac¬ 
 tion or crustation. 
 
 § VII. CLEAVAGE. 
 
 All regular formed minerals or crystals are capable of being cloven 
 or split in certain directions more easily than in others: and this cir¬ 
 cumstance is of the utmost importance to precious stones, as some of 
 them may be cloven to the thinnest leaves, and with great facility, 
 whereas it would require more power to split them in any other direc¬ 
 tion, and will yet exhibit irregular faces. We may also judge, from 
 the cleavage, to the external crystalline formation of a mineral, as 
 the cloven faces run, generally, parallel to one or the other crystal¬ 
 line planes ; and the cleavage of minerals is of essential benefit to the 
 mineralogist and lapidary. 
 
 § VIII. FRACTURE. 
 
 Fracture exhibits itself in minerals in directions where no cleavage 
 may be seen, and which is either— 
 
 1st, An even fracture, if the faces are on a plane without elevations 
 or excavations; 
 
 2d, An uneven; 
 
 3d, Conchoidal, exhibiting conchoidal excavations; 
 
 4th, Splintry, by showing small splintry parts on the face, which 
 yet adhere to the mass, but are more transparent; 
 
 5th, Earthy, when the faces show earthy parts on the fracture; 
 
 6th, Knotty, or prominent knots, which are left after the fracture. 
 
TREATISE ON GEMS. 
 
 13 
 
 § IX. SURFACE. 
 
 The surface of the crystallized, as well as non-crystallized mine¬ 
 rals, exhibits some difference, which is either— 
 
 1st, Smooth; 
 
 2d, Striped, provided with linear, fine or strong hollows; 
 
 3d, Drusy, if small prominent crystals, nearly equal to each other, 
 are perceived on the mineral; 
 
 4th, Uneven; 
 
 5th, Rough; or, 
 
 6th, Granular. 
 
 § X. HARDNESS. 
 
 The hardness of minerals forms an important character, it being 
 uniform in the same variety. It is that property by which minerals 
 or precious stones resist impressions of an instrument, or by scratch¬ 
 ing one another. There are two modes of testing the hardness of 
 minerals. 1st, By causing them to scratch such minerals as are 
 known to be standards for comparison; or, 2nd, By using such stand¬ 
 ard minerals for scratching the mineral to be examined. In the first 
 instance we use such minerals as are well known to have their 
 hardness; such as Diamond, Sapphire, Topaz, Quartz, Felspar, 
 Apatite, and Fluorspar: or we may use the file or point of a steel, which 
 is the mode practised by jewellers, who make use of fine English 
 files, and acquire sometimes a great skill in it. The soft minerals 
 and pastes will readily be touched by it; whereas Diamond, Ruby, 
 and Sapphire are not at all attacked. In mineralogy, however, a 
 simple instrument, contrived by Mohs, and called the scale of hard¬ 
 ness, is made use of; and jewellers might derive great benefit from 
 its application. This scale consists of a great number of minerals 
 joined together, each of which, in succession, possesses a degree more 
 of hardness than the former. 
 
 The Standard Minerals are as follows :•— 
 
 6. Felspar. 
 
 7. Quartz, or Rock Crystal. 
 
 8. Topaz. 
 
 9. Corundum. 
 
 10. Diamond. 
 
 1. Talc. 
 
 2. Gypsum, or Rock Salt. 
 
 3. Carbonate of Lime. 
 
 4. Fluorspar. 
 
 5. Asparagus Stone, 
 
 (Phosphate of Lime.) 
 
 We see, by the numerical order, that Fluorspar is 4 and Diamond 
 10 ; and for determining more particularly the hardness of a mineral, 
 the distance between each degree may be divided into decimals. In 
 order to test the hardness of any mineral, its comer is applied to the 
 
14 
 
 TREATISE ON GEMS. 
 
 members of the scale, and in such a manner as to begin from the 
 hardest: (for not scratching unnecessarily the softer) until we arrive 
 with it at that degree or mineral which is distinctly scratched. We 
 compare then, by means of a file, the hardness of the mineral to be 
 tested, with the last member of the scale that has not been scratched 
 yet; and we judge from the resistance which the mineral yields to 
 the file, and from the noise produced in scratching, whether this mine¬ 
 ral is as hard or actually softer than the last unscratched member of 
 the scale. Oriental Topaz, for instance, will not scratch the two 
 highest members of the scale, but the third, the Topaz = 8; and, 
 tested on the file, we find its hardness not to be under 9; since 
 Corundum, the standard on the scale, gives the same result as the 
 Oriental Topaz to the file; whereas the proper Topaz scratches at 
 No. 7. Precious stones have latterly been divided and arranged 
 according to their hardness, in the following three classes:— 
 
 1. HARD GEMS ; OR THOSE HARDER THAN Q.UARTZ. 
 
 Diamond. 
 
 Sapphire. 
 
 Ruby. 
 
 Chrysoberyl. 
 
 Spinelle. 
 
 Topaz. 
 
 Emerald. 
 
 Hyacinth. 
 
 Essonite. 
 
 Garnet. 
 
 2. SEMI-HARD JEWELS. 
 
 Rock Crystal. Opal. 
 
 Amethyst. Chrysolite. 
 
 Chalcedony. Lazulite. 
 
 Carneleon, and other simi- Obsidian, 
 
 lar ones. Turquoise. 
 
 3. SOFT PRECIOUS STONES. 
 
 Those softer than Fluorspar; Malachite, Amber, and Jet. 
 
 § XI. COHESION. 
 
 If the smallest particles of a mineral adhere together, that they 
 represent them either solid or fluid, or in any other similar condition, 
 then we consider this property the cohesion of a body; and we find 
 that in minerals which are brittle, the particles are coherent; and in 
 those which are friable, they are slightly: whereas a solid mineral 
 may lie brittle ; that is, if, by trying to separate small particles with a 
 knife or file, they lose their original condition, detach themselves with 
 noise, and fly about in form of powder. 
 
TREATISE ON GEMS. 
 
 15 
 
 2d, Pliable, if the separate particles remain in their condition. 
 
 3d. Mild, if those particles, after being detached, remain on the 
 cutting instrument. 
 
 4th. Extensible, if the mineral may be beaten into plates or drawn 
 into wire. 
 
 5th. Flexible, if those detached parts, that have changed their 
 position, will nor resume the same. 
 
 6th. Elastic, if they do resume their former position. 
 
 A liquid mineral may be either thus tough or thickly liquid. The 
 quantity of the cohesion of a mineral depends upon the hardness 
 which it possesses, and which has been considered above. 
 
 § XXI. SPECIFIC GRAVITY. . 
 
 The specific gravity of a body is its weight, when compared with 
 the weight of a quantity of water equal to its own bulk. When a 
 mineral is suspended in water, and weighed, it is lighter than when 
 weighed in air, by the weight of a quantity of water equal to the 
 bulk of the mineral so suspended. It is obvious, that a mineral, bulk 
 for bulk, heavier than water, could not sink in it; but if it should 
 sink, its weight must be diminished by exactly that of the quantity 
 of water it displaces. In order to find the specific gravity of a sub¬ 
 stance, it must be weighed in air by a hydrostatic balance, or by a 
 common balance, and then weighed in water, when its specific grav¬ 
 ity may be found by calculation, viz: by dividing its weight in air 
 by its loss in water. Specific gravity in minerals is a very remarka¬ 
 ble property ; since different substances possess, in most all instances, 
 a different gravity ; whereas all varieties of one and the same sub¬ 
 stance possess nearly the same specific gravity. By determining the 
 specific gravity of minerals With the hydrostatic balance, we proceed, 
 for instance : an unknown mineral having been weighed first in the 
 air, and then fastened by means of a hair and weighed in water. 
 Such as in the air 17.65 ; in water 12.35. The loss in water is, 
 therefore, 5.30; and this number indicates the loss of so much bulk 
 of water displaced by the mineral putting the specific gravity of 
 water 1.00 : x dividing 5 into 17.65, make it equal to 3.53, which is 
 the exact specific gravity of the mineral, and which is that of Esson- 
 ite. Instead of a hydrostatic balance, we may as well use Nichol¬ 
 son’s hydrometer, a simple and very convenient instrument, consisting 
 of a hollow glass cylinder (A,) and two dishes (B and C) filled with 
 lead, in order to keep the instrument upright. 4’he hydrometer is 
 put in a glass vessel (E,) filled with water, and used as follows: 
 
10 
 
 TREATISE ON GEMS. 
 
 1st. The weight is determined, which is required to sink the instru¬ 
 ment to the mark D in water. 
 
 2d. The mineral is put in the dish A over the weight noted, that 
 is required, in addition to the mineral, to sink the hydrometer to D. 
 
 3d. The same experiment is repeated by putting the mineral, after 
 being moistened and washed with water, in the dish C; and now is 
 A—B the weight of the mineral in the air, and B—b the weight of 
 a quantity of water equal in volume to that of the mineral. 
 
 For instance, let A = 32.8 
 
 B = 7.3 
 
 C = 15.8 
 
 there is (A—b) 32.8—7.3= 25.5 the weight of the mineral in the air. 
 
 (C—b) 15.8—7.3 =8.5 the weight of an equal quantity of water, 
 and proceed 8.5 : 25.5 = 1 : x 
 x =25.5 
 
 8.5 
 
 = 3.00, which is the proper specific gravity. For 
 determining the specific gravity of substances or minerals lighter 
 than water, or which float in water, it is neccessary to adhere to the 
 same method by the hydrometer. A heavier body, such as lead, after 
 determining the difference of weight, within or without the water, of 
 both together, and then of the heavier body alone, the specific gravity 
 of the lighter substance is the result. And for determining the spe¬ 
 cific gravity of liquids, by means of the hydrostatic balance, a glass 
 ball is applied to one of the arms, (its loss of weight in pure water 
 being known,) and, dipping the same in the liquid to be examined, any 
 addition and abstraction will result in the specfic gravity of the liquid. 
 The hydrometers of Beaume for the different liquids to be examined, 
 are employed with satisfactory results. 
 
 That the specific gravity has been known as far back as the 
 thirteenth century, and applied by the Oriental nations for determin¬ 
 ing the character of precious stones, is sufficiently proved by a work 
 written in that century by Mohammed Ben Manner. In fact, the 
 specific gravity is often, in connexion with the colour, quite essential 
 in determining a gem. 
 
 § XIII. COLOURS. 
 
 The colour of minerals and precious stones is one of the most 
 obvious and striking properties, but yet it is very difficult to distin¬ 
 guish accurately a mineral by the value, on account of the colours 
 
TREATISE ON GEMS. 
 
 17 
 
 very frequently being accidental, and depending upon the presence of 
 certain metallic oxides. The nature of the colouring principle has 
 been well known in former ages, where they had but erroneous views 
 of the same. So, for instance, it was believed that gold and tin were 
 the colouring principle of garnet; and Boyle, several centuries ago, 
 speaks of a metallic spirit that communicates the colour to precious 
 stones. Mineralogists have fixed eight primary or fundamental 
 colours, besides all the different shadings from one colour to the 
 other, on account of the colours being reflected from the different sub¬ 
 stances. They are generally divided into— 
 
 1st, Metallic; and, 
 
 2d, Non-metallic colours. 
 
 Metallic colours are the following 
 
 Copper, red. 
 
 Bronze, yellow 
 
 Brass, yellow. 
 
 Gold, yellow. 
 
 Iron, black. 
 
 The eight primary of the non-metallic colours are as follows:— 
 White, Gray, Black, Blue, Green, Yellow, Red and Brown. And 
 the shades of each of these primary colours are— 
 
 1. WHITE. 
 
 Snow-white, 
 
 Grayish-white, 
 
 Reddish-white, 
 
 Greenish-white, 
 
 Yellow-white, 
 
 Milk-white. 
 
 
 2. GRAY. 
 
 Bluish-gray, 
 
 Greenish-gray, 
 
 Pearl-gray, 
 
 Yellowish-gray, 
 
 Smoky-gray, 
 
 Ash-gray. 
 
 
 3. BLACK. 
 
 Grayish-black, 
 
 Brownish-black, 
 
 Yelvet-black, 
 
 Bluish-black, 
 
 Greenish-black. 
 
 4. BLUE. 
 
 Blackish-blue, 
 
 Prussian-blue, 
 
 Lasur-blue, 
 
 Sky-blue, 
 
 Indigo-blue, 
 
 Yiolet-blue, 
 
 Smalts-blue, 
 
 Lavender-blue, 
 
 c 
 
 Silver, white. 
 Tin, white. 
 Lead, gray. 
 Steel, gray. 
 
18 
 
 TREATISE ON GEMS. 
 
 5. GREEN. 
 
 Verdigris-green, 
 
 Grass-green, 
 
 Seladon, or Green Earth-green, 
 
 Epidote-green, 
 
 Asparagus-green, 
 
 Olive-green, 
 
 Mountain-green, 
 
 Blackish-green, 
 
 Garlick-green, 
 
 Oil-green, 
 
 Emerald-green, 
 
 Siskin-green. 
 
 6. YELLOW. 
 
 Lemon-yellow, 
 
 Honey-yellow, 
 
 Sulphur-yellow, 
 
 Ochre-yellow, 
 
 Straw-yellow, 
 
 Wine-yellow, 
 
 W ax-yellow, 
 
 Isabel-yellow, 
 
 Orange-yellow. 
 
 7. RED. 
 
 Carmine-red, 
 
 Rose-red, 
 
 Scarlet-red, 
 
 Brownish-red, 
 
 Crimson-red, 
 
 Flesh-red, 
 
 Cochineal-red, 
 
 Aurora-red, 
 
 Columbo-red, 
 
 Hyacinth-red, 
 
 Cherry-red, 
 
 Brick-red, 
 
 Peach-red, 
 
 Blood-red. 
 
 8. BROWN. 
 
 Chesnut-brown, 
 
 Yellowish-brown, 
 
 Reddish-brown, 
 
 Mica-brown, 
 
 Clove-brown, 
 
 Lignite-brown, 
 
 Hair-brown, 
 
 Silver-brown, 
 
 Blackish-brown. 
 
 The precious stones possess the colours in their highest perfection, 
 and their principal and intrinsic value depends mostly upon this prop¬ 
 erty ; and as most gems occur in various colours, the following table 
 will exhibit them, along with their specific gravity :— 
 
 LIMPID GEMS. 
 
 SPECIFIC GRAVITY. 
 
 Zircon, ----------- 4.41 to 4.50 
 
 Sapphire, - -- --.3.9 4.00 
 
 Diamond, -.3.5 3.6 
 
 Topaz, (Pebble) - --. 3.49 3.56 
 
 Rock Crystal, (False Diamonds, Lake 
 
 George, Trenton Falls,) ----- 2.69 
 
 Beryl, Aquamarine, -.- 2.67 2.68 
 
TREATISE ON GEMS. 
 
 19 
 
 RED GEMS. 
 
 Zircon, Hyacinth,.4.41 to 4.50 
 
 Garnet, (Oriental Garnet) .4.0 4.2 
 
 Sapphire, Ruby, -.4.0 
 
 Garnet, Bohemian Garnet. Pyrop, - - 3.7 3.8 
 
 Spinelle, Ruby Spinelle, Ruby Balais, - - 3.58 3.64 
 
 Diamond, - -- -- -- -- - 3.5 3.6 
 
 Essonite,.- - - - - 3.5 3.6 
 
 Topaz. Brazilian Topaz, (often burnt) - 3.52 3.56 
 
 Tourmaline, Siberite, Rubellite, - - - - 3.03 3.10 
 
 Rose Q,uartz. Bohemian Ruby, - - - 2.61 2.63 
 
 Carneleon, .. 2.5 2.6 
 
 YELLOW GEMS. 
 
 Zircon, - -- -- -- -- -- 4.41 4.50 
 
 Sapphire. Oriental Topaz, ----- 4.0 
 
 Chrysoberyl, -. 3.59 3.75 
 
 Topaz. Brazilian, Saxonian, and Syrian 
 
 Topaz, - -- -- -- - 3.50 3.56 
 
 Diamond, --------- - 3.5 3.6 
 
 Beryl, ----------- 2.67 2.71 
 
 Rock Crystal, Citron, ------- 2.60 2.69 
 
 Fire-opal, - - -- -- -- -- 1.90 2.12 
 
 GREEN GEMS. 
 
 Zircon, --------- - 4.41 4.50 
 
 Sapphire, Oriental Chrystolite, and Emerald, 3.9 4.00 
 
 Malachite, - -- -- -- -- - 3.67 
 
 Chrysoberyl, .- - - - 3.59 3.75 
 
 Spinelle,.3.58 3.64 
 
 Diamond, --------- - 3.5 3.6 
 
 Topaz. Aquamarine, ------ 3.49 3.56 
 
 Chrysolite, - -- -- -- -- - 3.33 3.44 
 
 Idocrase, - . .. 3.08 3.40 
 
 Tourmaline, (Brazilian and Maine,) - - 3.00 3.30 
 
 Emerald,.-. 2.67 2.73 
 
 Beryl, ------ . 2.67 2.71 
 
 Prase, -.-. 2.66 2.68 
 
 Heliotrope .- 2.61 2.63 
 
 Chrysoprase, . 2.58 2.60 
 
 Felspar, Amazon Stone,. 2.50 2.60 
 
20 
 
 TREATISE ON GEMS. 
 
 BLUE GEMS. 
 
 Sapphire,.-.3.90 to 4.00 
 
 Disthene, (Kyanite,). 3.63 3.67 
 
 Spinelle, -. 3.58 3.64 
 
 Diamond, .3.5 3.6 
 
 Topaz. Brazilian Topaz, ----- 3.49 3.56 
 
 Tourmaline, Indigolite, ----- - 3.00 3.30 
 
 Turquoise, .2.86 3.00 
 
 Beryl, Aquamarine, ------- 2.67 2.71 
 
 Dichroite (Iolite,) - -- -- - - - 2.58 2.60 
 
 Hauyne, - -- -- -- -- -- 2.47 
 Lazulite, - -- -- -.2.30 
 
 VIOLET GEMS. 
 
 Garnet, - -- -- -.4.0 4.2 
 
 Sapphire, Oriental Amethyst, ----- 3.9 4.0 
 
 Spinelle, - -- -- -- -- -- 3.58 3.64 
 
 Axinite, - -- -- -- -- -- 3.27 
 
 Tourmaline,.- - - 3.00 3.30 
 
 Amethyst, --------- - 2.65 2.78 
 
 BROWN GEMS. 
 
 Zircon, - -- -- -- -- -- 4.41 4.50 
 
 Garnet, - -- -- -- -- -- 4.00 4.20 
 
 Essonite, - -- -- -- -- -- 3.53 3.60 
 
 Diamond, - -- --.- 3.50 3.60 
 
 Tourmaline, - -- -- -- -- 3.00 3.30 
 
 Smoky Quartz, - -- -- -- -- 2.69 2.70 
 
 BLACK GEMS. 
 
 Diamond, - -- -- -- - - - 3.50 3.60 
 
 Tourmaline, - - - -. 3.00 3.30 
 
 Rock Crystal, Morion, ------ 2.69 2.71 
 
 Obsidian, - -- -- -- -- - 2.34 2.39 
 
 Pitch Coal, 1.29 1.35 
 
 Canned Coal, --------- 1.23 1.27 
 
 GEMS DISTINGUISHED FOR THEIR VARIOUS SHADINGS 
 OF COLOUR AND LIGHT. 
 
 Garnet, .----- - 4.00 4.20 
 
 Sapphire, Star Sapphire, ----- 3.90 4.00 
 
TREATISE ON GEMS. 
 
 21 
 
 Chrysoberyl, 
 
 Hypersthene, 
 
 Labrador Spar, 
 
 Dichroite, 
 
 Cat’s-eye, 
 
 Adularia, 
 
 Felspar, 
 
 Precious Opal, 
 
 Hydrophane, 
 
 3.70 
 - 3.38 
 
 to 3.80 
 
 2.71 
 
 2.75 
 
 
 2.60 
 
 2.56 
 
 2.73 
 
 - 2.50 
 
 2.60 
 
 2.50 
 
 2.60 
 
 - 2.00 
 
 2.10 
 
 1.90 
 
 2.00 
 
 A number of precious stones do not possess a local colour, but 
 merely a tinge or a shade of a colour; and these we distinguish by 
 the following degrees of dark, high, light and pale coloured or tinged. 
 Another distinction may be detected in precious stones as possessing 
 either one or more colours, or a variegated colour; or as being spotted, 
 painted, stained with the different colours. These latter characters 
 are, however, more proper to the semi or common precious stones, 
 than to gems. 
 
 § XIV. LUSTRE. 
 
 The quantity of light which is reflected from the surface of minerals 
 and precious stones is indicated by the lustre; and it is an important 
 character for distinguishing minerals, inasmuch as it is almost uni¬ 
 form in the same species. It exhibits itself either— 
 
 A, in the strength ; or, 
 
 B, in the kind. 
 
 The first depends in precious stones from the beauty of the sub¬ 
 stance, and from the manner in which they are cut and polished; 
 and we distinguish— 
 
 1 , highly lustry; 
 
 2 , lustry; 
 
 3, little lustry; 
 lustre is called fiery. 
 
 The kinds of lustre are- 
 
 1 , metallic; 
 
 2 , adamantine; 
 
 3, resinous; 
 
 4, shining; 
 
 5, faint lustre; 
 
 and the highest degree of 
 
 4, vitreous; 
 
 5, pearly; 
 
 6 , oily lustre. 
 
 And often we perceive the transitions from one lustre into the 
 other: and we describe a mineral as possessing the lustre between the 
 adamantine and vitreous lustre, and approaching to the pearly lustre. 
 
22 
 
 TREATISE ON GEMS. 
 
 § XV. TRANSPARENCY. 
 
 The capacity of minerals and precious stones to permit the passage 
 of the rays of light through them, so that an object held on the one 
 side may be clearly seen on the other, is called transparency: and 
 according to their power in this property we divide it in— 
 
 1st, Transparent, if the object is perfectly visible; 
 
 2d, Semi-transparent, if not distinctly visible; 
 
 3d, Translucent, if the object is but feebly seen through, and yet 
 clear towards the light; 
 
 4th, Translucent on the edges; and, 
 
 5th, Opaque, if no light at all is transmitted through a mineral. 
 
 § XVI. REFRACTION. 
 
 When the rays of light pass from one substance (rarer medium) into 
 another, (denser medium,) they are always refracted or bent towards a 
 perpendicular line passing through that substance (medium): and so 
 also when the rays pass from a denser into a rarer medium, they are 
 refracted in a contrary direction, or from such a perpendicular; and 
 objects are multiplied when seen through the inclined contiguous 
 surfaces of any transparent medium. The light coming from the object 
 being refracted by the oblique surface, passes to the eye in a different 
 direction from that of the real object, and there are as many images 
 seen as there are oblique planes. According to the manner in which 
 the rays are refracted, the power is divided into—1st, simple; and, 2d, 
 double refraction. An object may be seen double or treble ; it is yet 
 the simple refraction, since the direction of the rays of light are only 
 changed by the direction in which they happen to strike the transpa¬ 
 rent surface. When an image of a single object is doubled, if seen 
 through the parallel surface, it is called double refraction. Almost 
 all precious stones possess the power of double refraction in a greater 
 or less degree; and we may distinctly see the single refraction in 
 quartz of a prismatic form, and that of double refraction in the rhom¬ 
 bic limestone, called the Iceland spar. But all precious stones do 
 not possess this property in the same degree ; and on that account we 
 specify the same by calling it a, treble; b, moderate; c, high; and 
 d, very high degrees of double refraction. This property, depending 
 upon the interior structure of the mineral, is of intrinsic value in 
 testing the most valuable gems. But it has always been difficult in 
 practice to determine with accuracy this character; for the observer 
 is often disappointed in his experiments. Fissures in the substances 
 partly contribute to the disappointment, and sometimes the general 
 
TREATISE ON GEMS. 
 
 23 
 
 structure of the mineral will not permit of an accurate test, as it may 
 not yield the proper face or facette, or the plate may be too thick for 
 obtaining the proper refraction; it therefore cannot be employed with¬ 
 out much practical skill. 
 
 §. XVII. PLAY OF COLOUR. 
 
 The property of many precious stones to display different colours 
 in smaller or greater points of brilliancy, when the rays of the sun 
 are directed towards them, or by changing the position of the gem, is 
 called a play of colours: such we perceive it in the Diamond, pre¬ 
 cious Opal, and Labrador Spar. 
 
 § XVIII. IRIDESCENCE. 
 
 If the fissures contained in the interior of a transparent precious 
 stone, represent coloured rings, resembling colours of the rainbow, it 
 is called iridescence. 
 
 § XIX. CHANGE OF COLOUR. 
 
 The property of those precious stones, to display two different 
 colours, if held in different directions, is called the change of colour: 
 such we observe in the Cat’s-eye, Moon-stone, and Iolite; also, in the 
 Chrysoberyl. This property has generally been called opalescence, 
 which, in my opinion, is the same as iridescence. 
 
 § XX. LOSS OF COLOUR. 
 
 Many precious stones, when exposed more or less to atmospheric 
 air, and from the oxydation of the colouring principles contained in 
 them, lose their colour; which may, however, very often be restored, 
 either by laying them in a dark or moist place: such as Rose Quartz 
 and Chrysoprase; or may be restored by leaving it some time in oil: 
 such as the Opal. 
 
 § XXI. LUSTRE SHINE. 
 
 A soft waving shine of lustre is often perceived in the interior of 
 several gems; also that of a star, such as we detect in the Star 
 Sapphire. 
 
 §XXII. PHOSPHORESCENCE. 
 
 Many precious stones possess the property of giving a greater 
 or less distinct light, either by mechanical means, artificial heat, 
 or the effect of the rays of the sun: this is called phosphores¬ 
 cence. The Diamond, for instance, if merely rubbed with wool, or 
 a brush, exhibits this property. Other precious stones, if rubbed 
 
24 
 
 TREATISE ON GEMS. 
 
 together, such as two pieces of Quartz : others, again, by being 
 scratched with iron, steel, or copper, such as Dolomite and Blende. 
 Some of them, such as Diamond, White Topaz, and Fluorspar, 
 become phosphorescent by warming with the hand; and others, 
 again, by exposing them to the rays of the sun; such as Diamond, 
 Amber, Fluorspar, and several other gems. The light representing 
 the phosphorescence is white or coloured, and but momentary in its 
 duration. 
 
 § XXIII. ELECTRICITY. 
 
 Many precious stones become electric by friction, pressure, or heat. 
 Electricity manifests itself by attracting or repelling light and move- 
 aide substances. There are two kinds of electricity—1st, the positive; 
 2 d, the negative, vitreous, or resinous electricity; and according to 
 their surface, when either smooth or rough, all gems may be made 
 electric: many of them, such as Quartz, Mica, Sapphire, and 
 Barytes, when rubbed only with the dry hand, or piece of silk, 
 woollen, or fur: others, again, such as Tourmaline or Topaz, by 
 being heated. These are called then pyroelectric. Most crystals 
 acquire positive electricity at one end and negative at the other. 
 If they terminate in a different number of faces at each extremity, 
 the end having the greatest number of faces is always positive. 
 
 All polished stones acquire positive electricity by friction; while, if 
 the same stones (except the Diamond) have their polish destroyed, 
 they acquire negative electricity. The most simple apparatus by 
 which electricity may be ascertained is a brass or copper needle, with 
 two small balls at each end, and, being isolated, is suspended on a 
 steel point. In experimenting, the gem to be tested being rubbed, 
 and then brought near one of the balls, the strength or power of 
 attracting the same indicates the degree of electricity contained in the 
 body. The power of retaining the electricity acquired by rubbing, 
 for a longer time, varies in different minerals and gems; and as the 
 latter are all electric, this property may sometimes be used as a dis¬ 
 tinguishing character as to the length of retaining the electricity. 
 Abbe Haiiy found, in his experiments, that many precious stones 
 lose their electric power after a few moments, whereas some will 
 retain the same for twenty-four hours longer. The Brazilian Topaz 
 affected the needle, even after thirty-two hours. 
 
 § XXIV. MAGNETISM. 
 
 The capacity of minerals to act upon the magnetic needle is called 
 magnetism. There are but few gems that possess this property; and 
 
TREATISE ON GEMS. 
 
 25 
 
 the Chrysolite, Essonite, and Garnet owe their magnetic properties to 
 the metallic oxides they contain. A common magnetic needle is 
 used for performing this experiment. 
 
 § xxv. TOUCH. 
 
 Precious stones produce a peculiar impression to the senses; and 
 most gems impart a cold feeling when touched, indicating, at equal 
 temperatures, a much colder feeling than pastes. 
 
 § XXVI. TASTE AND SMELL. 
 
 Many minerals have a taste, on touching with the tongue, and 
 they are— 
 
 1, As Yitriol; 4, Alkaline; 6, Bitter; 
 
 2, Sweetish, as Alum ; 5, Cooling ; 7, Urinous. 
 
 3, Saline; 
 
 Many minerals produce a smell by rubbing, or merely holding 
 them in the hand: such as Bitumen, Pyrites, Carbonate of Lime, 
 Barytes, Gypsum, Q,uartz, and Coal. 
 
 § XXVII. CHEMICAL CHARACTERS. 
 
 Although mineralogy could not exist, as a science, without the aid 
 of chemistry, and whole systems, as well as the constituent parts of 
 minerals, have been established by the knowledge of the chemical 
 characters, yet it is difficult to apply these characters for distinguishing 
 the gems or precious stones, which would be destroyed by such an 
 examination, and we can, for that purpose, only employ splinters or 
 fragments of any mineral or precious stone. The most simple mode 
 of proceeding is to test— 
 
 1st, The greater or less fusibility of the mineral with or without a flux; 
 
 2d, Their behaviour before the blowpipe, an instrument indispensa¬ 
 ble to the mineralogist, and at the same time highly convenient; and, 
 
 3d, The action of acids upon them. 
 
 All these characters, however, have no effect upon gems, as many 
 of them are either infusible or fusible with the greatest difficulty by 
 the addition of a flux. 
 
 § XXVIII. COMPOSITION OF GEMS. 
 
 The attention of writers, as far back as 1502, has been directed to 
 the establishment of some hypothesis as to the composition and origin 
 of the gems, and many fabulous views were entertained in respect to 
 their formation. 
 
 There was also connected with such hypothesis a species of medical 
 superstition as to their effect. Boyle (1672) thought that all gems 
 
 D 
 
26 
 
 TREATISE ON GEMS. 
 
 were originally formed from clear limpid water, and that they received 
 their colour and other properties from their metallic spirit. Others 
 considered a peculiar earth, called the noble or precious earth, as the 
 principal ingredient of the precious stones. Bruckman (1778) recog¬ 
 nized Q,uartz as the principle of the gems. Bergman thought that 
 gems were all composed of-the same ingredients, such as alumina, 
 silex, and lime, and that the different proportions produced the differ¬ 
 ent species ; and the older mineralogists determined the character 
 of the gems by their hardness, lustre, structure, and resistance to acids. 
 But modern chemistry has ascertained the component parts, and 
 other characters of the gems, with more certainty; and it is sufficiently 
 proved that the principles contained are the earths: such as silica, 
 alumina, and lime; that some contain their peculiar earth, (such is 
 the case in Zircon, Emerald, and Chrysoberyl,) and that the Dia¬ 
 mond, at the head of gems, consists of pure carbon, &c. 
 
 § XXIX. GEOLOGICAL CHARACTERS. 
 
 The origin, locality, and geological characters of gems are various, 
 and it was formerly supposed that the trap formation was their 
 matrix; but it is ascertained that we find them distributed in rocks 
 of different ages and kinds, either as accidental mixture—such as 
 Garnet in gneiss and micacious shiste—or in drusy cavities, such as 
 the Emerald, which occurs in druses of argillaceous slate and mica¬ 
 cious shiste; and many precious stones are found in gangues. 
 Many gems are found at a distance from their original bed, on 
 secondary or diluvial strata, or in the beds of rivers, mixed with 
 their sand. Thus, Zircon is found in Ceylon in regular beds; and 
 likewise we find in Ceylon, after much rain, the Topaz, Zircon, 
 and other gems. This happens more frequently in the beds of the 
 rivers, and then the gems appear often in the shape of pebbles, show¬ 
 ing that those hard stones, carried away from their original beds, 
 have been rolled and rounded by the streams and rivers, although 
 they retain sometimes their crystalline structure, on account of their 
 hardness. 
 
 § XXX. GEOGRAPHICAL DISTRIBUTION. 
 
 The locality of the gems bears some highly interesting characters, 
 inasmuch as we may sometimes judge, from their appearance, of the 
 climate of their locality; and it seems as if the countries of the hot 
 zones had been particularly favoured by nature in producing the most 
 precious gems, or that those hot-beds were more propitious to the 
 formation of the blossoms of the inorganic world. Comparing, for 
 
TREATISE ON GEMS. 
 
 27 
 
 instance, Spinelles and Zircons, from Siberia, with those of Ceylon and 
 Pern, we find the first to be dark and of impure colour, as if express¬ 
 ing the cold, unfriendly northern climate; whereas the latter glitter 
 with full brightening, and bear all those properties and beauties for 
 which gems are so highly esteemed. Often, too, we find the gems 
 collected in particular countries, or isolated spots of our globe: such as 
 the most precious gems from the East Indies and Brazil, where, sin¬ 
 gular enough, they occur with the precious metals: such as, for 
 instance, the Diamond in company with gold and platina in Brazil. 
 Some of the gems have likewise been hitherto discovered in one clear 
 spot of one continent, and are then exhausted: such as the Rubellite, 
 of Maine, United States ; the Iolite, from Connecticut, United States ; 
 and the Lazulite, from Persia. 
 
 § XXXI. PRACTICAL DIVISION AND NOMENCLATURE OF GEMS. 
 
 The artists have made no use, in their arrangement and nomen¬ 
 clature of the gems, of the advanced state of mineralogy, as a science; 
 and although they have been newly classified by the mineralogist, 
 according to their scientific characters, the practical artist arranges 
 them according to such properties as principally attract the eye: such 
 as colour, transparency, and lustre. Gems have, in consequence, 
 received their names from their colour: as Ruby, from its red colour; 
 Sardonyx, Yellow Onyx; since they often call gems by such gloss 
 or colour as a distinctive property of different species by the same 
 name, according to their colour. For instance, they call ruby, on 
 account of their red colour, either the Corundum, the Spinelle, or the 
 Topaz; and, on account of its blue colour, the Sapphire; green, the 
 Emerald ; yellow, the Topaz ; and violet, the Amethyst: and thus 
 gems of the same colour, but of different composition, were arranged 
 under the same head. The artist confounds, under the name of a 
 Brazilian Ruby, either a light rose-red Spinelle, or a Topaz approach¬ 
 ing to the red colour. The name of the country, or locality, is often 
 sufficient to name gems of equal colour, but of different shadings, and 
 of more or less vivid lustre. That by the name of Oriental Chryso¬ 
 lite is meant a yellowish-green Sapphire, and by that of Saxonian 
 Chrysolite, a pale wine-yellow Topaz. Many gems have always 
 been known under the name of Oriental gems, partly because they 
 were first obtained in the East, and partly because they stood, from 
 their excellent properties, in higher estimation than those from any 
 other country; and then those gems of any other country which 
 equalled in quality. Those from the East were likewise called 
 
28 
 
 TREATISE ON GEMS. 
 
 “ Oriental” in opposition to those, less valuable, which were called 
 “ Occidental” gems. Subsequently, all gems distinguished for their 
 properties were called Oriental gems, even when their locality was 
 not the East. Thus, for instance, they call that precious Opal, so 
 well distinguished for its beautiful play of colours, the Oriental Opal, 
 although never found there; likewise the purest and most valuable 
 Emerald, which in such perfection only occurs in Peru, the Oriental 
 Emerald. 
 
 § XXXII. HISTORY OF THE GEMS. 
 
 Those precious stones which are now called the gems have been 
 known in ancient times but very little, or not at all; and the first 
 notice given of them is in the Bible, where it is stated that the high- 
 priest wore one stone on his gold scarf, and twelve gems set in gold 
 plate, called the Urim and Tliumim, each of which represented a 
 tribe. It appears that the Hebrews borrowed the names of their gems 
 from the Egyptians, and few of those gems named in the holy 
 Scriptures correspond in any respect with those at present known in 
 our mineralogical books, with the exception of the Sapphire. The 
 Greeks appear to have been but little acquainted with the gems, as 
 they did not use them as ornaments in the Trojan wars; and Homer, 
 when speaking of the treasures of those times, does not make any 
 mention of the gems. Theophrastus and Pliny have described some 
 gems of their time but very imperfectly and confusedly; and their 
 descriptions are so replete with vain fancies, that it is difficult even to 
 identify any from their descriptions. They began then to attribute 
 most wonderful powers to the gems; to give fabulous descriptions; 
 the most singular and perverted views in regard to their origin; and 
 it was said that they had great influence upon health and beauty, 
 riches, honour, and good fortune. They were called, when worn, 
 Amulets. They were brought in connection with the planets, the 
 twelve constellations, and the seasons of the year; and a certain gem 
 was worn every month, which was said to have then its peculiar 
 influence and healing virtues. Such superstitious ideas have been 
 transmitted to our times. The gems corresponding to the different 
 months, and also to the twelve Jewish tribes are the following:— 
 
 January .... Hyacinth.Dan. 
 
 February .... Amethyst.Gad. 
 
 March.Jasper.Benjamin. 
 
 April.Sapphire.Issachar. 
 
 May.Agate.Naphtali. 
 
 June „ . . . . Emerald.Levi. 
 
TREATISE ON GEMS. 
 
 29 
 
 July.Onyx.Zebulon. 
 
 August .... Carneleon.Reuben. 
 
 September . . . Chrysolite .... Asher. 
 
 October .... Beryl.Joseph. 
 
 November . . . Topaz.Simeon. 
 
 December . . . Ruby.Judah. 
 
 The artists have made certain alterations between some gems cor¬ 
 responding to the months, and the tribes represented in the Urim and 
 Thumim, and they consider May to be represented by Emerald; 
 
 June, . . by Chalcedony, Onyx, or Agate ; 
 
 July, . . . Carneleon; 
 
 August, . . Sardonyx; 
 
 October, . . Aquamarine; 
 
 December, . Chrysoprase, Turquoise, or Malachite. 
 
 In the early ages similar views were entertained in the East, and 
 many of them are yet prevalent. Thus, among others, the Persians 
 believe that Spinelle affords joy, and protects them against bad 
 dreams. The Indians believe in large Diamonds to bring back to 
 the family. The Rajah of Mattan, a district of the Western Borneo, 
 possessed a Diamond of 367 carats. The Ruby possesses a talisman 
 in the East, which is not shown ever willingly to the friends, but it 
 is considered ominous if it contain any black spots. The Chinese, on 
 the contrary, present the same stone as a testimony of friendship. 
 The Peruvians adore the Emerald as their deity. Many of those 
 fabulous views were probably brought from the East to Europe; for 
 we find, in the middle ages, similar views entertained by Marbodus, 
 Bishop of Rennes, who wrote a book on the miraculous powers of the 
 gems. The twelve Apostles were likewise represented symbolically 
 by the gems, and they were called “ the Apostle Gemssuch as— 
 
 Jasper, . . 
 
 for St. Peter; 
 
 Sapphire, 
 
 . St. Andrew; 
 
 Chalcedony, 
 
 . St. James; 
 
 Emerald, * . 
 
 . St. John; 
 
 Sardonyx, 
 
 . St. Philip; 
 
 Carneleon, . 
 
 . St. Bartholomew; 
 
 Chrysolite, . 
 
 . St. Matthew; 
 
 Beryl, . . . 
 
 . St. Thomas; 
 
 Chrysoprase, 
 
 . St. Thaddeus; 
 
 Topaz, . . 
 
 . St. James the Less 
 
 Hyacinth, 
 
 . St. Simeon; 
 
 Amethyst, 
 
 . St. Matthias. 
 
30 
 
 TREATISE ON GEMS. 
 
 The ancients, induced by the beauty of the gems—such as the pure 
 and high colour of the Emerald, the vivid and high lustre of the 
 Diamond, and the agreeable reflections of the Opal—had then begun 
 to use them as ornaments and jewellery, and to take pains in fitting 
 them better to their purposes; and although they did not, in those 
 times, understand the cutting and polishing in the same manner as 
 in the present, yet they endeavoured to work them in all possible 
 shapes, by rubbing off the corners, or polishing the natural faces. 
 They generally fixed the gems on strings; they also tried to carve 
 figures representing deities, religious costumes, historical events, ex¬ 
 ploits of celebrated generals, or the heads of great men. 
 
 § XXXIII. SCULPTURE IN GEMS. 
 
 The art of carving was well known to the ancients, and those were 
 called gems, in the proper sense of the word, which had figures or 
 letters engraved on a very small compass, the works of which we, at 
 this day, cannot help admiring. 
 
 The gem-sculpture, or the glyptic art, (or lithoglyptics,) is the art 
 of representing designs upon precious stones, either in raised work 
 (cameos) or by figures cut into or below the surface (intaglios). The 
 first were most natural to the rising art, and to the use of seals; 
 whereas the latter were used as ornaments, and to which the most 
 precious materials were employed, and according to the state of the 
 art. They did not understand engraving in Diamonds, and few in 
 other gems: they employed only the softer stones, the common 
 precious stones, such as Carneleon, Onyx, Jasper, &c. ; they also 
 used paste, or artificial coloured glass composition, for their engrav¬ 
 ings. Their mode of working was very simple: the polishers pre¬ 
 pared their stones on a plate, by means of the powder of harder 
 stones, either round, oval, flat, or in shield form, according to the 
 designed subject, and then left to the sculptors the subject of the 
 engraving, which was done by means of iron, or diamond splinters 
 mounted in iron. It was not until the year 1500 that Ambrosius 
 Caradossa was the first who discovered cutting the Diamond. He 
 prepared the figure of a patriarch for Pope Julien II. He also dis¬ 
 covered the first traces of sculpture among the Jews, Persians, and 
 Egyptians; and in the traditions of the holy Scriptures, Moses, for 
 instance, had the names of the twelve tribes of Israel engraved in the 
 gems used by the high-priest. Solomon possessed a seal: Alexander 
 presented his seal to Perdicas. Augustus had a sphinx engraved on 
 his seal; but the Indians and Persians engraved mostly mythological 
 
TREATISE ON GEMS. 
 
 31 
 
 animals or priests in their gems ; the Egyptians, beetles, which they 
 adored, and which are called the scarabege. “ Abraxes ” were the oldest 
 gems, which had the representation of fantastical animals, with the 
 above word in Greek language, engraved. The Plienicians, Hetru- 
 rians, and Greeks learned the art of carving from the Egyptians ; and 
 from them it was carried to the Romans, where it was lost, with the 
 decline of the empire, not until the fifteenth century, under the Popes 
 Martin Y. and Paul II. The art was revived again by some fugi¬ 
 tive Greeks in Italy. Great merit is also due to the Medicians for 
 the revival of the art; and Giovani was considered the first in Italy. 
 The talisman , or those carved gems with the Arabian letters, belong 
 to those times. Precious stones with layers, veins, or such as Onyx, 
 Sardonyx, &c., were employed by the ancients, Avith great skill, in the 
 carving of cameos, where we find the head of one colour, and hair 
 and dress carved out of the other layer of the stone. Very often the 
 subjects were mythological, and this mode of carving or sculpture has 
 been imitated by modern artists; and it is sometimes with difficulty 
 that we are enabled to distinguish the ancient from the modern works, 
 and the only authentic authority for the antiquity of the cameo or 
 intaglio is in the excavation from ancient monuments, except in a few 
 instances, where we may be enabled to judge on their different 
 antiquity. When they are either of unnatural, stiff drawings, large 
 heads, hands, and feet, stiff streaks resembling the hair or the eyes 
 drawn in the length; or we find that some gods, representing the 
 peculiar gems, (such we see all sculptures of Bacchus, and what relates 
 to him,) were executed in Amethyst, being the colour of wine; and all 
 nymphs, Neptune, or fish, in Aquamarine, &c., the colour of water. 
 We find also, in Germany, traces of sculpture, in the fourteenth and 
 sixteenth centuries; and the oldest known artist, Daniel Engelhard, 
 at Nuremburg, died 1552 ; also Lucas Kilian; and the best artist, 
 Nater, died in 1705. England and France had likewise very distin¬ 
 guished artists in carving. A full history of gem-sculpture may be 
 found in the Encyclopedia Americana, pp. 403-405. 
 
 § XXXIV. ON GRINDING. 
 
 The art of grinding gems is of more modern origin ; it is the art 
 of cutting the gems, and other precious stones into figures, bounded 
 by many planes, in order to increase their valuable properties, along 
 with the lustre and transparency Avhich they already possess: also, 
 by polishing their faces, is the work of the lapidary. In the year 
 1290 a society of lapidaries Avas formed at, Paris, and in 1385 there 
 
32 
 
 TREATISE ON GEMS. 
 
 were diamond-cutters at Nuremburg ; but it was not until 1456 that 
 Ludwig Yan Bergen invented the art of polishing the diamond 
 with its own powder; and they then began to cut the gems accord¬ 
 ing to mathematical principles, and brought the art in modern times 
 to the greatest perfection. There is a great difference in gems, which 
 are mostly procured from the Indians in the rough or polished state, 
 easily to be detected by the imperfections. They look more upon the 
 size of the stone than upon the cut, which is generally irregular and 
 devoid of symmetry. We observe this in the two celebrated Dia¬ 
 monds of the Dey of Persia, the Dariainur —brilliant sea —(1 and 
 1 a) and the Kuinur —brilliant mountain —(2 and 2 a ): 
 
 (1 a.) 
 
 'ATHrmr 
 
 (2 a.) 
 
 the one is worn on the left arm, and the other on the right knee. 
 
 By considering the Diamond belonging to the Crown of France, 
 which weighs one hundred and thirty-six and a quarter carats, is four¬ 
 teen lines long, thirteen and a quarter lines broad, and nine and a quarter 
 lines thick, and which is known by the name of Regent , we can then 
 more distinctly discriminate the irregular and unmathematical cut. 
 
TREATISE ON GEMS. 33 
 
 The gem-grinders are divided in three classes: 1st, the Diamond ; 
 2d, the gem ; and, 3d, the jewellery-grinders. 
 
 The Diamond-grinder divides his work in—a, slitting or cleaving ; 
 6 , cutting; c, grinding; and d, polishing. 
 
 Before operating upon the Diamonds, some preliminary experi¬ 
 ments, as to their soundness, are made: for very fine, imperceptible 
 fissures may, at the end of a laborious grinding, terminate either in 
 cracking or spoiling the stone; and for this purpose the following two 
 modes are pursued: either the Diamonds, or any other gems to be 
 examined, are steeped in Canada Balsam, or in oils of sassafras or 
 anniseed, in which fluids they are well turned around, whereby the 
 minutest fissure, by its changed refraction of light from that of the 
 rest of the stone, may be detected; or the Diamond is exposed to a 
 great heat, and is then thrown into water, when it will crumble to 
 pieces should any cracks have been within it. The Diamond, 
 although the hardest of all known substances, may yet with facility 
 be cloven with steel tools, the blow being properly applied. The 
 octohedrons are best fitted for cleaving ; they are generally, however, 
 somewhat rounded, and in order to cleave them, those planes which 
 are to be cloven are left bare, and the rest is coated with a composi¬ 
 tion of rosin and brickdust; the bare plane is now rubbed with 
 another sharp-edged Diamond until a furrow is obtained, which will 
 render the planes suitable for applying the cleaving instrument, and 
 this operation is repeated with every plane. Diamonds that are not 
 fit for being cloven are called by the Dutch “ divelsteene ” (devil- 
 stones). Large Diamonds, which are too precious to be exposed to a 
 dangerous cleavage, are sawed by means of a fine steel wire, moist¬ 
 ened with oil and Diamond-powder. 
 
 Mr. Mawe gives the following description of the art of cutting and 
 polishing Diamonds:— 
 
 <{ The object of cutting and polishing the Diamond is twofold:— 
 First, to divide the natural surface of the stone in a symmetrical 
 manner, by means of a number of highly-polished polygonal planes, 
 and thus to bring out to the best advantage the wonderful refulgence 
 of this beautiful gem; and, secondly, by cutting out such flaws as 
 may happen to be near the surface, to remove those blemishes that 
 materially detract from its beauty, and consequently from its value. 
 
 “ The removal of flaws is a matter of great importance: for, owing 
 to the form in which the Diamond is cut, and its high degree of 
 refrangibility, the smallest fault is magnified, and becomes obtrusively 
 
 E 
 
34 
 
 TREATISE ON GEMS. 
 
 visible in every facet. For this reason, also, it is by no means an 
 easy matter, at all times, to ascertain whether a flaw is or is not 
 superficial; and a person with a correct and well-practised eye may 
 often purchase, to great advantage, stones which appear to be flawed 
 cjuite through, but are, in fact, only superficially blemished. 
 
 “ The first thing the artist has to do, when a rough Diamond is 
 put into his hands, is to examine carefully in what direction the stone 
 may be cut, so as to afford the greatest breadth, or spread , as it is 
 technically termed, after the flaws, if any, shall have been taken out. 
 So great a stress is laid, by modern fashion, on the superficial extent 
 of a brilliant, that the old rules for proportioning its dimensions are 
 now nearly obsolete : the best cutters have entirely discarded the use 
 of measures, and, in forming the facets, trust wholly to an accurate 
 and well-practised eye. The direction being determined on, the artist 
 must lie well aware which are the hard points and which the soft 
 ones ; the former being those solid angles of the original octohedron 
 which it is necessary to cut directly across, and the latter those solid 
 angles which are to be obliquely divided. A degree of force which 
 may be safely applied, and is even requisite in making a section 
 through the former, will be very apt to flaw and tear up the laminae 
 when applied to the latter. On these accounts it probably is, that 
 the fatiguing and even painful process of performing this part of the 
 business by hand, is not yet superseded by the use of machinery. 
 
 “ These preliminary matters being settled, the Diamond is imbedded 
 in strong cement, fixed at the end of a stout spindle-shaped stick, 
 about a foot long, with that portion only projecting, the removal of 
 which is to form the first facet. The instrument employed for this 
 purpose is another Diamond, fixed in a stick similar to the former, 
 with one of the solid angles projecting. In order to collect the powder 
 and shivers that are detached during the process, the cuttiug is per¬ 
 formed over a strong box, four or five inches square, furnished with a 
 false bottom, perforated with excessively minute holes, in order to sift, 
 as it were, the dust from the shivers; and also with two upright iron 
 pegs, fixed on the sides, for the workman to support and steady his 
 fingers against, while with a short repeated stroke, somewhat between 
 scratching and cutting, he is splitting off or more laboriously wearing 
 away the Diamond in that part where the facet is to be placed. This 
 being done, the cement is softened by warming it, and the position of 
 the Diamond is changed, in order to bring a fresh part under the 
 action of the cutting-diamond. When, in this slow and laborious 
 way, all the facets have been placed upon the surface of the Diamond, 
 
TREATISE ON GEMS. 
 
 35 
 
 the cutting is completed. The stone, if examined by a moderate 
 magnifier, now presents ragged, rough edges ; and a broken, foliated 
 surface, with a glistening lustre on those facets that are nearly in the 
 direction of the natural laminae, and on the other facets a more even 
 surface, but of a dull opaque grayish-white colour. 
 
 “ The shape of many Diamonds is so irregular, that it is necessary 
 to remove pieces of considerable magnitude in order to bring them to 
 a form proper for cutting. Where the lines of these proposed sections 
 coincide with the natural lamellar structure of the stone, the workman 
 has recourse to the delicate, and perhaps somewhat hazardous, opera¬ 
 tion of splitting the Diamond, by which a double advantage is obtained. 
 In the first place, there is a great saving of time; and in the second 
 place, the slices or shivers are themselves sufficiently large to admit of 
 being cut and polished. The method of splitting is made a great 
 mystery; thus much, however, may be mentioned, that when the 
 direction in which the section is to be made has been determined on, 
 it is marked by a very fine line, cut by the point of another Diamond: 
 the stone is afterwards fixed by strong cement, in the proper position, 
 in a block of wood, and then, by the application of a due degree of 
 force, the section is effected. 
 
 “ The Diamond being thus, by the joint action of splitting and 
 cutting, brought to the required form, the next object is to polish the 
 facets, and at the same time to redress any little inequalities that may 
 have taken place in the cutting. The polishing-mill is an extremely 
 simple machine, consisting of a circular horizontal plate of cast-iron, 
 fourteen or fifteen inches in diameter, called a skive, suspended on a 
 spindle, and capable of being put into rapid motion by means of a 
 larger wheel, five or six feet in diameter, and turned by an assistant. 
 From the centre to the circumference of the iron plate are lines or 
 shallow grooves, formed by rubbing it in that direction with a fine¬ 
 grained gritstone: these grooves serve to retain the mixture of oil and 
 Diamond-powder with which the plate is charged. In order to keep 
 the Diamond perfectly steady while the polishing of each facet is 
 going on, the following contrivance is had recourse toA copper cup, 
 (called a dopp,) about three-quarters of an inch in depth and in width, 
 and furnished with a stem about four inches long of stout copper wire, 
 is filled with plumbers’ solder, which also projects in a conical form 
 beyond the rim of the cup: in the apex of this cone, the solder being 
 softened by heat, the Diamond is imbedded, with one of the facets 
 projecting. The stem of the cup is now put into very powerful 
 pincers, which screw up with a nut and a wrench or lever, and thus 
 
36 
 
 TREATISE ON GEMS. 
 
 hold it perfectly tight. The handles of the pincers (called tongs ) 
 are of wood, are broad, and terminated by two feet, about an inch 
 high, so that when laid horizontally, they are supported exactly as a 
 pair of candle-snuffers is, the studs fixed to the handles of the snuffers 
 representing the legs of the pincers, and the single stud near the point 
 of the snuffers representing the inverted copper cup holding the Dia¬ 
 mond is placed on the plate, the pincers resting on their legs on the 
 wooden bench or table that supports the plate, and pressing at the 
 same time against an upright iron peg; the broad part of the pincers 
 between the legs and the Diamond, is then loaded with weights, both 
 to steady the machine and to increase the pressure of the Diamond 
 against the skive. Matters being thus adjusted, a little oil and Dia¬ 
 mond-powder is dropped on the plate, it is set in motion at the rate of 
 about two hundred revolutions in a minute, and the process of grind¬ 
 ing down, and at the same time of polishing, is begun. The Diamond 
 is taken up and examined from time to time, and is adjusted so as to 
 give the facet its true form. The heat occasioned by the friction is at 
 all times pretty considerable, and when the pincers are heavily loaden, 
 it occasionally increases to such a degree as to soften the solder and 
 displace the Diamond. This is a serious accident, frequently occa¬ 
 sioning a flaw in the Diamond, and always tearing up the surface of 
 the skive, so as to damage it very considerably. There is room on 
 the skive for three or four Diamonds at the same time; and, to give 
 each its proper share of attention, is as much as one person can well 
 manage. The completion of a single facet often occupies some hours.” 
 
 The polish is often produced by rubbing the Diamond with a cloth 
 or bare hand. The form which the gems have to receive from the 
 lapidary varies according to the condition of the stones, and the skill 
 of the artist depends upon the right selection of the form, which shall 
 correspond with the natural structure of the gems. A good cut has 
 the greatest influence on the lustre and beauty of the gems; the 
 colourless and limpid gems, for instance, require a different treatment 
 from those which have a play of colours. With a Diamond, the form 
 must correspond, as much as possible, with its natural or original 
 shape, in order to save great trouble of grinding, and the waste thereby 
 produced. Transparent gems ought not to be cut too thick; the rays 
 of light might otherwise be refracted too much, or prevented from 
 penetrating through them at all: in the first instance, the lower facets 
 do not act in correspondence with the upper, and the rays are much 
 distributed before reaching the eye. Gems of such description are 
 
TREATISE ON GEMS. 
 
 37 
 
 called clotty. On the other hand, if the gems are too thin, their 
 beauty, elements, and general value are likewise diminished. There 
 is a definite proportion of the thickness to the breadth of colourless or 
 limpid gems, whereas the cut of the coloured gems depends upon the 
 intensity of the colour. 
 
 § XXXV. FORMS OF THE DIAMOND. 
 
 Diamonds were formerly cut according to their natural form, and 
 mostly in the plains of the octohedron. They were called then point 
 Diamonds (pierris de Nature, or pointes ingenues). 
 
 The following forms are now, more or less, adopted by the Dutch 
 and English Diamond cutters:— 
 
 A, The Brilliant. This cut displays to greatest advantage the lustre 
 of the Diamond: it may be considered as obtained by two truncated 
 pyramids, united together by one common base, the upper pyramid 
 being much more deeply truncated than the lower. It is 
 >c formed— a, Of the crown , or that part of the stone which 
 remains visible after the stone is mounted ; b, The collet , 
 or lower part; c, The girdle , or the common base for the crown and 
 collet; d, The table, that plane which is formed by the truncature of 
 the upper pyramid ; e, The bisel, that space which lies between the 
 girdle and table; and, f, The collet-side , that space between the 
 girdle and collet. The English lapidaries cut the girdle sharp, whereas 
 the Dutch leave it broad: the crown amounts to one-third and the 
 collet to two-thirds of the whole height of the Diamond; the table 
 amounts to four-ninths of the diameter of the brilliant, whereas the 
 collet only needs one-fifth of the size of the table. The table and 
 collet are regular octagons, and the facets occupied by the bisel are 
 eight lozenges, with twenty-four triangles, and are called the star- 
 facets ; the facets occupied by the collet-side are four irregular penta¬ 
 gons, alternating with as many irregular lozenges, radiating from the 
 collet as a centre, and are bordered by sixteen triangular 
 facets adjoining the girdle, and are generally called the 
 pavilion or cross-facets. According to the number of 
 facets, the brilliants receive their names, either of double 
 or treble brilliant: the double brilliant is surrounded by 
 i two rows of facets on the bisel, which are triangular, and 
 meet each other; the treble brilliant has fifty-eight planes, 
 fifty-six facets, table and collet, thirty-two facets of which 
 are in the bisel in three rows; the star and pavilion facets are trian- 
 
38 
 
 TREATISE ON GEMS. 
 
 gular, the intermediate ones are four-sided, and on the collet-side are 
 twenty-four facets. 
 
 The English double brilliant consists of twenty-four facets, table 
 and collet, sixteen of which terminate in the form of a star in the bisel. 
 
 Brillionets or Half-brilliants are those Diamonds the spread of which 
 is too great in proportion to their depth, and the crown is only cut like 
 a brilliant, but the collet-side is wanting. 
 
 B , The Rose-Diamond has but a crown, and no collet; 
 it is formed of equilateral triangles, and consists of two rows 
 of three-sided facets ; those on the girdle are pavilion, and 
 the others star-facets. But there are variations in the 
 number of facets: the Dutch roses have eighteen pavilion and six 
 star-facets; others have six pavilion and six star-facets, or twelve 
 pavilion and six star-facets ; and some, also, have twenty-four three- 
 sided pavilion and twelve star-facets. The Rose Diamond is only 
 that Diamond, the proportion of whose breadth to its depth is too 
 much extended, and which would not, without much loss, make a 
 good brilliant. There are fragment Rose Diamonds, which are very 
 small, and Ear-drop Roses. 
 
 C, The Table-Diamond is that stone which is very 
 flat and of little depth, and which reflects but little lustre: 
 they have a table with four planes and eight facets; and, 
 in order to make the best of their lustre, they receive a 
 brilliant cut. 
 
 D The Bastard-Diamond , is that Diamond whose cut is mixed 
 up from the above forms. 
 
 There are a few more forms given to those Diamonds which are 
 found unfit for any of the above cuts, such as the Thick-Stones, the 
 Portrait Diamonds, the Senail Diamonds, which are, however, all 
 unfit for the above cuts. 
 
 § XXXVI. FORM OF GEMS. 
 
 The gem lapidary occupies himself not only with grinding the 
 common and rare gems, but also pastes, &c.: he uses likewise wheels, 
 but of different material than those for Diamonds. His wheels are 
 either of copper, if for very hard stones; of lead or pewter for softer 
 stones; and he has likewise polishing wheels. If any wheel is too 
 soft for very hard stones, he cuts furrows in them, which are then 
 filled out with rottenstone or tin ashes ; or if very hard stones, such as 
 Sapphire, are to be ground, the Diamond powder is used for the 
 same: likewise are tin wheels used for hard stones ; water, or also oil 
 
TREATISE ON GEMS. 
 
 39 
 
 of vitriol, are used for moistening the wheels. The gems, in order to 
 grind them or to give their facets, are likewise cemented into a 
 handle, at the end of which is a composition of rosin and brickdust. 
 Particular attention is required in grinding the coloured gems, as the 
 greatest effect may be produced by their thickness, and pale-coloured 
 gems require to be left thicker than darker ones; and, on the other 
 hand, they ought not to be left too thick, as they appear too dark, and 
 thereby lose their lustre. The same proportion in the manner of 
 cutting the crown and collet of the coloured gems has to be observed 
 as with the brilliant, namely, the crown ought to be one-third and 
 the collet two-thirds in size of the depth of the whole stone; if the 
 gem be of a pale colour, the collet ought to be three-fourths of the 
 size; and if of a darker colour, much less : the table of those coloured 
 gems which require to be heightened ought to be waved somewhat, 
 whereas it ought to be even in darker gems. The forms of the coloured 
 gems, which they receive in cutting, resemble, in many instances, those 
 of the Diamond, but the following are the additional cuts they receive, 
 according to the nature of the shape and colour of the stone :— 
 
 A, The Step or Pavilion cut. The planes, which 
 are long and small, decrease towards the table and collet, 
 
 «and terminate in steps; the crown has usually two and 
 the collet four or five facets on each side; the form of the 
 stones may be of four, six, eight, or twelve sides, or may 
 be long or round. This cut is particularly applicable to coloured gems, 
 as it reflects the light in a high degree, by which the play of colour is 
 much raised; and it is, at all events, to be preferred in the collet of 
 coloured gems even to those brilliants in pavilion: the crown may 
 be of any form whatever. 
 
 B, The Mixed-facet cut, is a compound of bril¬ 
 liant and pavilion cuts, the first being on the crown; 
 it is a very favourite cut for coloured gems, and con¬ 
 tributes much in raising the lustre. 
 
 C, The Elongated Brilliant-facet cut , which, if 
 the brilliant facets are on the crown elongated, and the 
 collet has a pavilion cut, is very appropriate to long 
 and thin stones. 
 
40 
 
 TREATISE ON GEMS. 
 
 D, The Table cut, having either an even or conchoidal 
 table, with one or two rows of facets, in a circular form, 
 around it; a very useful form for sealstones. 
 
 E , The Double-facet cut , the crown having two 
 rows of facets, and the collet the pavilion form; this 
 cut is well adapted to such stones as may conceal any 
 faults, flaws, or fissures, by the same. 
 
 F, The Cabochon cut is either flat, convex, or double-convex that 
 is arched ; it may be on both sides, or only on one. This 
 cut is particularly applicable for semi-transparent gems, or 
 those which display their peculiar colours: such as the Opal, Moon¬ 
 stone, &c.; or collect the light in a small space, on one or several 
 points, according to the convexity they have received. 
 The Cabochon cut may have one, two, or more rows of 
 facets; and opaque stones receive with advantage the 
 facets over the whole surface. Garnets, for instance, 
 which are generally of a dark colour, are cut en cabochon, the lower 
 plane excavated in a circular form and the upper plane all around 
 with facets. Other gems, the interior faults of which cannot be con¬ 
 cealed, may be improved by this cut, giving them more transparency, 
 vivid colour, and a greater degree of fire. 
 
 It mostly depends on the skill and discrimination of the artist in 
 the choice of the cut in all gems. 
 
 —-—: 
 
 
 
 
 ^: 
 
 7 
 
 § XXXVII. COMMON LAPIDARY. 
 
 Such common precious stones as are suitable to be cut for snuff¬ 
 boxes, rings, grinding mortars, seals, and ear-rings, are wrought by the 
 common lapidary by means of copper or iron wheels revolving verti¬ 
 cally. The tools are generally of iron, and sometimes brass; some 
 are flat like chisels, gouges, ferrules, and some others have conicular 
 heads. The polish is given with rotten stone, on a tin plate; or 
 with crocus martis, on a wooden plate covered with felt. The cuts 
 applied by the workman are either even, cup-shell form, excavated, 
 elevated, or quite simple: facets are not used by him. 
 
 Mr. Mawe describes a lapidary’s apparatus, fit for polishing mine¬ 
 rals, shells, &c., and which may be placed in a parlour, where every 
 operation of polishing, on a scale sufficiently large, may be effected, 
 and pebbles may be slit of three or four inches diameter: it consists 
 of the following mills :— 
 
 1st, A lead mill, or wheel, to be used with emery and water, for 
 grinding down substances preparatory to polishing. 
 
TREATISE ON GEMS. 
 
 41 
 
 2d, A pewter mill, to be used with rottenstone a little wet, for polishing. 
 
 3d, Tin plate, properly prepared, the edge of which is to be used 
 with Diamond powder, to slit or cut hard stones asunder. 
 
 4th, Wood mills, covered with leather, &c., for polishing marble, 
 alabaster, shells, or other soft substances. 
 
 § XXXVIII. ENGRAVING. 
 
 The value of many precious stones is increased by engraving 
 them. The common gems have, for several centuries, been used in 
 heraldry. In Italy, Germany, and England, we find the coat of arms 
 of distinguished or noble families engraved on stone. The machine 
 used for that purpose is like that of the glass cutters, with this differ¬ 
 ence, that there are finer and harder instruments, and sometimes 
 Diamond splinters, required for this work. Before the stone can be 
 cut or engraved, its surface, after having received the proper shape 
 and form required, is rubbed with emery, glass, or leaden wheels: 
 the artist now makes his drawing with a brass pin, and executes it 
 afterwards with his tools. On hard stones he uses Diamond powder; 
 on soft, emery and oil. 
 
 The engravings of armorial bearings, single figures, devices, &c., 
 on any gem, is performed by the means of a small iron wheel, the 
 ends of the axis of which are received within two pieces of iron in a 
 perpendicular position, that may or may not be closed as the operation 
 requires; the tools are fixed to one end of the axis, and screwed firm; 
 the stone to be engraved is then held to the tool, the wheel set in 
 motion by the foot, and the figure or device gradually formed. 
 
 Difficult works are executed after models of plaster of Paris, of clay, 
 or other substances; the polish is afterward given on wheels, provided 
 with brushes or with rotten-stone. The semi-transparent and opaque 
 stones are more used for engraving than the transparent gems, because 
 the drawing will not show distinctly through them, on account of the 
 great refraction of light; the same is the case with iridescent or shining 
 stones. The engravings are generally bas-relief or raised; those 
 having layers are mostly preferred for cameos: for instance, the Onyx, 
 Sardonyx, and Chalcedony; also, Wood-opal, which is constantly 
 exported from Germany for the Italian artists in Rome. 
 
 § XXXIX. SAWING AND DRILLING THE GEMS. 
 
 Gems and precious stones often require to be sawed in different 
 directions, which operation is performed on a machine like that of a 
 lapidary, with the exception of a polishing-plate, which is substituted 
 
 F 
 
42 
 
 TREATISE ON GEMS. 
 
 by a cutting-plate having sharp ends, or also by fastening the stone 
 on a stand and moving continually a fine iron or copper-wire stretched 
 in a bow, which is moistened with emery and oil. Care has, how¬ 
 ever, to be taken not to let the stone grow too hot, as the heat may 
 crack or make the stone spotty. The Chinese use strings spun over in 
 preference to the wire, they having the advantage of keeping the emery 
 sticking to them and of accelerating thereby the operation. For drill¬ 
 ing the gems or other precious stones, a Diamond set in steel is made 
 use of to move to and fro by a bow, or also of the common engraving 
 machine, the drilling instrument of which consists of an iron point, to 
 which is fastened a Diamond-splinter, which is pressed upon the stone 
 while it is revolving on the plate. 
 
 § XL. GRINDING AND POLISHING MATERIALS. 
 
 The materials for grinding and polishing, vary according to the 
 hardness of the gem : the Diamond-powder is obtained by grinding real 
 Diamonds, which are unfit for use, with each other in a hollow cylinder 
 of cast-iron, in which another one exactly similar is used for the most 
 costly and hardest gems. Corundum, Sapphire, Topaz-powder, and 
 emery-powder, are commonly used for grinding and polishing the 
 Diamond. It is well to remark that emery is often adulterated by a 
 mixture of quartz and oxide of iron, or by garnet or iron-powder. 
 Emery fit for the use intended, requires to be properly pulverized and 
 levigated. According to Hawkins, the following method is pursued 
 in England :—The emery is pulverized in an iron mortar and passed 
 through different sieves, one finer than the other, the first is levigated 
 with oil which keeps it in better suspension above water, and accord¬ 
 ing to the time in which the powder settles, the different numbers are 
 hereby obtained. 
 
 For polishing the different precious stones, hard and soft gems, the 
 Diamond-powder and emery are mostly used. Rotten-stone, tin-ashes, 
 pumice-stone, oxide of iron, English jewellers red, all of which are used 
 in their finest pulverized state: but a great deal depends upon the polish 
 which a gem has received, all of its other superior qualities being 
 thereby called forth. 
 
 § XLI. RAISING THE COLOUR OP GEMS. 
 
 Since the colour is one of those characters which is the most tempt¬ 
 ing in the sale of the gems and jewellery, all means are necessarily 
 employed for heightening the same and covering any real defect. Foil 
 of small thin metallic substance coloured or uncoloured, either of fine 
 
TREATISE ON GEMS. 
 
 43 
 
 silver or copper, is placed under the gem in the back of the mounting, 
 which heightens the colour and lustre, particularly of the transparent 
 gems. Almost all gems were formerly set in black coloured backs, 
 composed of burnt ivory-black and gum mastic, but are now mostly 
 set a jour , which is, leaving the lower part of the stone uncovered in 
 setting, and only mounting around the girdle, an old method, and 
 very applicable to perfect stones where no defects require concealment. 
 
 Foiling materially heightens the lustre of gems. The Rose Diamond 
 always requires it on account of its flat form. There are many 
 gems which would not produce any effect without the foil. It is 
 therefore used whenever a pale or impure colour is to be raised, or 
 where the gems are to be protected against dust or moisture in order to 
 produce a uniform shade of colour; the foil forms then a suitable 
 application. 
 
 The colouring of the foil is generally performed by the jewellers.— 
 Isinglass first dissolved in water and afterwards boiled in spirits of 
 wine, and then strained, is the mass or body to which the colours are 
 afterwards added, which are also soluble in water. 
 
 For producing a red colour, the best material is Carmine, 
 
 “ Blue, - - - Litmus, 
 
 “ Yellow, - Saffron. 
 
 To produce the different shades and various colours, the above are 
 united with each other. Very clear stones are sometimes painted on 
 the back, such as Chrysoprase, Carneleon, &c. The Paris jewellers 
 are very skilful in painting k stones of inferior value so as to deceive 
 even professional men ; it is for this reason that gems when set, ought 
 not to be purchased; the valuable gems which have a foil on their 
 back are mostly set in such a manner that they may be examined 
 without the same. Foiled gems may likewise be distinguished by 
 holding the table of the set gem on the nail of the thumb and observ¬ 
 ing the passage of the light through the crown. 
 
 In the East, rubies are never set with foil, but a cavity is made from 
 below and filled with finely polished gold, which raises its lustre 
 remarkably. 
 
 Fissures, flaws, or veins in the interior of the gems are mostly con¬ 
 cealed by the foil, and when near the girdle, are covered by the 
 mounting. 
 
 The defects of stones are sometimes concealed by colouring the 
 case with mastic and ivory-black, and according to circumstances leave 
 blank the spot of the faulty stone, or covering only the spot, for pro¬ 
 ducing a uniform colour. Another and not unusual method of con- 
 
44 
 
 TREATISE ON GEMS. 
 
 cealing fissures, flaws, or other faults, is to cut those stones with many 
 faults, the momentary detection being thereby prevented from the play 
 of the refracting light and the lustre. The colour of many gems is 
 raised by the fire, which acts in a peculiar manner on many of them; 
 thus the Brazilian Topaz assumes a very fine, pale red coluor by 
 burning; the process of affecting this colouring is very simple, viz : 
 after wrapping the topaz in a sponge, ignite the same and keep it 
 burning until consumed. 
 
 The Zircon sometimes assumes a better colour after having been 
 subjected to a high degree of heat. Amethysts having dark spots, 
 may be calcined for a short time in a crucible containing sand and 
 iron-filings, under which process they mostly lose those faults; but if 
 exposed to an excess of heat, they will lose their colour altogether and 
 become as white as quartz. The Oriental Carneleon assumes, after 
 burning, a fine colour, and in Hindostan those carneleons which are 
 found detached in the mines, are cut up and burnt on the spot. Very 
 fine cracks are sometimes produced in mounting the stones, which 
 may be repaired and concealed successfully by means of garlick juice. 
 When the stones are broken by the same operation, they may be 
 cemented by gum mastic. 
 
 § XLII. SETTING OF GEMS. 
 
 The gems are generally fastened or set at the girdle in a box or rim 
 of metal: limpid and faultless gems are always set a jour, (i. e.) with¬ 
 out backs, since they appear then to the best advantage, and if the 
 gem is intended to display its full size and colour, the a jour setting is 
 only fastened by small shanks or claws. The good setting of a gem 
 very much increases its value and beauty. The material for mount¬ 
 ing the limpid gems is silver, which displays to more advantage than 
 gold. In order to increase the colour or lustre of large gems, they are 
 often surrounded by smaller gems, such as small Roses, Rubies, Eme¬ 
 ralds, Garnets, Turquoise, &c. 
 
 The jewellers wax used for mounting the gems, is made of three 
 parts rosin, one part bees-wax, and four parts fine brick-dust. 
 
 § XLIII. CLEANING THE GEMS. 
 
 The following composition I have found to be the best material for 
 thoroughly cleaning the gems, particularly when set:—Take one part 
 flower of sulphur, and two parts rotten-stone or bone-ashes, which 
 when mixed is used by rubbing it on a piece of buck-skin and with 
 that on the gems, alternately with a stiff hair-brush, and at last with a 
 softer skin or cloth, which will remove the dust. 
 
TREATISE ON GEMS. 
 
 45 
 
 § XLIV. IMITATIONS OF GEMS. 
 
 Pliny mentions the imitation of jewels by glass fluxes, and it is 
 sufficiently proved that the ancients were far advanced in this art. 
 The Egyptian mummies were provided with glass-buttons of green 
 and blue colour, and during the reign of the Roman empire, coloured 
 glass was very general; and we find antique cameos carved in various 
 coloured glass, representing the Onyx, likewise coloured-glass cemented 
 with real Onyx, but they never attained such perfection in their art 
 as to set at defiance the skill of the artist and jeweller to distinguish 
 between the genuine and spurious ones. The imitation of gems may 
 be divided into three classes :— 
 
 A, The Pastes. The basis of these imitations is a fine, pure, and 
 white glass composition, called Sir ass, after its inventor, S trass of Stras- 
 bourgh, in the seventeenth century, who first conceived the necessity 
 of imitating the real gems by their hardness, specific gravity, and re¬ 
 fraction of light. He accomplished the task sofar that in many instan¬ 
 ces, either all three, or one or the other of his objects were attained. 
 The strass is composed of silex, (quartz, flint, or pure sand,) potash, 
 borax, red-lead, and sometimes arsenic. To three-hundred parts of 
 silex add ninety-six parts potash, twenty-seven parts borax (prepared 
 from the Boracic acid,) and five-hundred and fourteen parts of white- 
 lead, and one part arsenic: or in another method, mix seven ounces and 
 twenty-four grains quartz with ten ounces seven and a half drachms 
 red-lead, three ounces and six drachms pure pearlashes, three twenty- 
 seven-thirtieth drachms borax, and twelve grains arsenic; the mixture 
 is put into a covered hessian crucible and kept at a great heat in a pot¬ 
 tery furnace for twenty-four hours. The longer the mass is kept in a 
 fluid state, the harder and clearer it will be when turned out and cooled. 
 This discoloured strass is used by the lapidaries for imitating the 
 Diamond, rock-crystal, and white Topaz. 
 
 For imitating the coloured gems, various colouring ingredients are 
 employed. To obtain that intensity of colour approaching nearest to 
 the original gem, it is experience alone which can guide the manufac¬ 
 turer. In order to imitate the uniform and intense colours, the Strass 
 colouring ingredients are to be of the finest powder, and very closely 
 mixed, the mass to be exposed to a very great heat, in that state left 
 for nearly thirty hours, so that the cooling is gradual. Numerous 
 establishments in Germany and France, are now engaged in the manu¬ 
 facture of the Strass and coloured pastes, each of which possess secrets 
 acquired by their experience, for producing these articles in the greatest 
 perfection. I will now quote a few imitations of some of the most 
 
46 
 
 TREATISE ON GEMS. 
 
 precious gems, and shall in the second part of this essay always allude 
 to those which are imitated, with the receipts for producing such imita¬ 
 tions, obtained from the best sources and my own experience, viz :— 
 
 A, Artificial Topaz. Take of perfectly white Strass one ounce and 
 six drachms, glass of Antimony thirty-seven grains, and cassius pur¬ 
 ple one grain ; or take to six ounces Strass, half a drachm of crocus 
 martis. 
 
 B, Artificial Ruby. This may either be obtained from the first 
 mixture for the Topaz with an addition of eight parts more of Strass, 
 and left for thirty hours in fusion ; when taken out and fused before 
 the blow-pipe, it yields a most beautiful Oriental Ruby. Five ounces 
 Strass and one drachm oxide manganese yield likewise, but not so 
 fine a Ruby. 
 
 C, Artificial Emerald. To one pound Strass, take one drachm of 
 verdigris and fifteen grains crocus martis. 
 
 I). Artificial Sapphire. Take to eight ounces Strass, fifty-two 
 grains pure oxide of cobalt. 
 
 E, Artificial Amethyst. To eight ounces Strass, add thirty grains 
 oxide of manganese, twenty-four grains oxide of cobalt, and forty 
 grains cassius purple; or to one pound Strass, twenty grains oxide 
 manganese, and one grain oxide of cobalt. 
 
 F, Artificial Aquamarine. To six ounces Strass, add twenty-four 
 grains glass of antimony, and one and a half grains oxide of cobalt. 
 
 G, Artificial Syrian Garnet. To one thousand grains Strass 
 add five hundred grains glass of antimony, four grains cassius purple, 
 and four grains oxide of manganese. 
 
 It will now be necessary to know the distinguishing characters be¬ 
 tween the real and artificial gems, as they so closely resemble each 
 other that a superficial inspection will not always enable the inspector 
 to discriminate between them ; they are as follows :— 
 
 1. The hardness, which may be tested on the grinding machine, 
 on which the fine quartz sand will immediately attack the pastes, or 
 by scratching on it with a real onyx, to which the pastes will imme¬ 
 diately yield. 
 
 2. The small air bubbles in the pastes, may more or less be detected 
 with a good magnifying glass. 
 
 3. The cold touch will never remain for any length of time on the 
 pastes as on the real gem. 
 
 4. The breath remains much longer on the pastes, on account of 
 
TREATISE ON GEMS. 
 
 47 
 
 their bad conducting power, than on real gems. The specific gravity 
 and electricity, may likewise indicate the difference,—but I never 
 depended upon them alone, and I will mention that I once examined 
 the specific gravity of an artificial Topaz which fully corresponded 
 with that of a Brazilian Topaz. The electricity will indicate the 
 difference between real and artificial gems from the time ; for real gems 
 retain, after being rubbed, their electricity for from six to thirty-two 
 hours, whereas, the artificial ones only retain it from forty to sixty 
 minutes. 
 
 6, The Doublets. This mode of imitating the real gems is called 
 the doubling, when a quartz, cut and polished, is cemented by means 
 of gum mastic to another coloured paste, whereby the whole stone 
 assumes the colour of the lower paste. If a real gem is employed 
 instead of the quartz, as the surface and the quartz or paste is cemented 
 below, it is called half doubling. This adulteration is carried on to a 
 very great extent in the East Indies, where they paste any thin gem 
 to a paste corresponding in colour. The concave doubling is effected 
 by excavating the inside of a quartz or paste. The cavity being filled 
 with a coloured fluid, and the other part afterwards cemented on it, 
 will, when well executed, present so uniform a colour that it is difficult 
 even for a judge to detect the deception. The surest method of 
 detection is to put the specimen in question in hot water or alcohol, by 
 which the gum mastic will be dissolved. When set, the only way of 
 finding out the adulteration, is to put it reversly on the nail of the 
 thumb, when the false refraction of light or the rainbow colours will, 
 with certainty, determine their identity. 
 
 C, The Burning. This mode of adulterating the real gems, is 
 performed by colouring cut and polished quartz specimens and throw¬ 
 ing them into a solution of permanent pigment, such as a solution of 
 indigo, decoction of cochineal, solution of ammoniacal copper; the 
 small cavities produced by the heat will absorb the fluids. The Topaz 
 is burnt by itself, with or without the absorption of a pigment, as also 
 the Spinell, and the Quartz ; Chalcedony is, however, frequently burnt 
 for imitating the Onyx, and to engrave therein the Cameos and the 
 Intaglios. 
 
 It may be remarked, however, that since the introduction of coloured 
 pastes, very few adulterations of this kind are now practised, and we 
 see but rarely such doublets and burnt stones. 
 
48 
 
 TREATISE ON GEMS. 
 
 § XLV. PRICE AND TRADE IN GEMS. 
 
 It is difficult to determine the price of gems without reflecting upon 
 all the circumstances, such as beauty and uniformity, the play, the 
 lustre, and the vivacity of the colours, as also on the perfect cut, the 
 polish, the rare locality or the size of the individual gems. It de¬ 
 pends upon the trade of the various countries from whence they come, 
 and are sent to the staple, and what quantity of such valuable gems 
 may be had at one time at any of the great cities : so we find that 
 diamonds were often sold at a much less price in London and Paris 
 than in Brazil. The principal trade, however, is as yet carried on in 
 Brazil and the East Indies, although in no comparison so prosperous 
 as in former years. The gems are sold by weight, such as carat and 
 grain. One carat is L equal to four grains, and forty-four carats are 
 equal to one ounce. The name carat is derived from the word 
 Kuara, the coral tree, (Erythrina,) the red pods of which, when dry, 
 were formerly used for weighing gold dust, and each of them weighs 
 four grains, which is equal to one carat. 
 
 § XLVI. GEMS FOR OPTICAL PURPOSES. 
 
 A few years ago, Messrs. Trecourt and Oberhauser laid before the 
 Parisian Academy lenses of diamond, sapphire, and ruby, which were 
 used in connection with glass lenses in microscopes; they were of 
 nine-tenths millim, in diameter. The diamond lens magnified two 
 hundred and ten times, that of sapphire two hundred and fifty-five 
 times, and that of ruby two hundred and thirty-five times, in a linear 
 extension. 
 
 A letter was lately published from Sir David Brewster, on a curious 
 optical phenomenon that had occurred in the construction of diagonal 
 lens. The Diamond, previous to working, had all the appearance of 
 internal brilliancy ; but, after being polished, it presented a series of 
 stratified shades, which rendered it useless for the required purpose. 
 It afterwards appeared that lapidaries were acquainted with this 
 appearance, which rendered them extremely unwilling to take the 
 risk on themselves, of cutting up Diamonds for optical purposes. On 
 a minute examination of this phenomenon, it appeared that these 
 different shades occurred in regular strata, each section being about 
 one-hundredth part of an inch, and each stratum having a different 
 focus, and being of different degrees of hardness and specific gravity. 
 The inferences drawn from the above facts were:—that the Diamond 
 was a vegetable substance, and that its parts must have been held in 
 
TREATISE ON GEMS. 
 
 49 
 
 solution and subjected to different degrees of pressure at different 
 stages of its existence. If, on the contrary, as it has been generally 
 believed, subject to the laws of crystallization, its crystals must neces¬ 
 sarily have been homogeneous. 
 
 G 
 

 I 
 
 
 
 
 
 
 
 V 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ■ , 
 
 
 
TREATISE ON GEMS. 
 
 PART II. 
 
 TREATMENT OF THE INDIVIDUAL GEMS. 
 
 I. DIAMOND. 
 
 We will now proceed to the consideration of the different gems, 
 which have mostly been arranged according to their hardness. 
 
 Diamond: Diamant (German), Adamant {of the ancients), Almas 
 (Oriental), Diamant (French). The name Diamond is derived from 
 the Greek, Adamas, meaning invincible, and referring to the hardness 
 of the Diamond. The Syrians are said to have first known the 
 Diamond, and it was in early ages the subject of trade to the people 
 of the East. The Carthagenians are said to have carried on their 
 trade with the Etrurians, who procured their Diamonds from the inte¬ 
 rior of Africa. Pliny mentions six species of Diamonds, among 
 which, however, the Indian are to be considered the true, in contra¬ 
 distinction to the quartz crystals, which were likewise called Diamonds 
 in those times. The Diamond was highly esteemed, and many 
 medicinal virtues were attributed to them, particularly against mania, 
 and as an antidote for poisons; and the Diamond was worn in the 
 rough state. The art of cutting it with its own powder was discovered 
 in 1476, by Lewis Yan Berghen. In the beginning they cut it in 
 the table form, with one row of facets on the surface: afterwards, 
 in 1520, they made use of the Rhomb cut; and the form of brilliants 
 was invented in the reign of Louis XII. The cardinal Mazarin was 
 the first who had the Diamond polished in this form, and some of 
 which yet belong to the crown of France. For a long time philoso¬ 
 phers vainly speculated as to the nature of the Diamond : first it was 
 considered as a mineral, consisting of Silica; but Newton was the 
 earliest (1675) who expressed himself as to the constitution of 
 Diamonds. He judged, from the great refraction of light, that it 
 must be a combustible body; and a series of experiments with it, 
 tested afterwards by different naturalists, proved the same to be pure 
 
52 
 
 TREATISE ON GEMS. 
 
 carbon. The first trial was made in 1694, by the members of the 
 Academy at Florence, where Diamonds were volatilized within the fo¬ 
 cus of a mirror; and Bergman first classified the Diamond to the com¬ 
 bustible bodies, and mentions of having cut the head off the gems. 
 
 Various views existed in regard to the origin of the Diamond: some 
 considered it as a secretion of a vegetable substance ; others as origi¬ 
 nating from volcanic or plutonic revolution. The Indians believe 
 Diamonds are continually regenerating and growing to this date ; and 
 the inhabitants of Pharrah, in Hindostan. affirm that the quantity of 
 Diamonds by no means decrease, but that on the contrary the soil 
 will yield a supply after fifteen or twenty years, which was then 
 exhausted. 
 
 Numerous experiments have been instituted to produce an artificial 
 Diamond from several substances which contain carbon, and by the 
 application of a high degree of heat. Dr. Hare, in Philadelphia, 
 succeeded in melting down mahogany charcoal so as to produce a 
 metallic appearance, by his deflagrator. Professor Silliman likewise 
 made similar experiments with plumbago, which produced small 
 globules, some of which were so transparent that they could not be 
 distinguished from the genuine Diamond. Vannuxen, who examined 
 the globules obtained from fused charcoal, found them to contain 
 iron and carbon, which led him to the conclusion that the 
 charcoal had not undergone a real fusion.. Cagniard de Latour 
 pretended to have discovered the ingredients for imitating Diamonds 
 of some size, but Thenard proved those small chr.ystals of the appear¬ 
 ance of Diamond, to be some silicates of peculiar composition, which, 
 according to Arago, polarized the light in a different angle than 
 Diamonds. All speculative experiments to imitate this most precious 
 gem, by all the compounds of carbon, have as yet been frustrated. 
 
 The Diamond is found chrystalized mostly of the form of an 
 Octahedron, (composed of two four-sided pyramids, united by their 
 bases) or rhombic dodecacedon, rarely of a cube; but the planes of 
 the angles are often rounded or bevelled. The foliated passages are 
 distinctly parallel to the faces of the octahedron, in which direction 
 they may always be slit. Fracture is conchoidal; surface is smooth, 
 often rough or striped, and sometimes covered with a scaly crust; 
 transparent, also semi-transparent; exceedingly vivid lustre, called 
 the Diamond, or adamantine lustre ; and when polished of splendid 
 fire ; limpid, and likewise passing into the greatest variety of shadings 
 from white and gray, sometimes from yellow, green and brown, but 
 more rarely tinged from orange, red, blue or blackish. 
 
TREATISE ON GEMS. 
 
 53 
 
 The Diamond being the hardest of all substances, yields to no file; 
 its streak powder is white or greyish; it becomes phosphorescend 
 by the rays of the sun, and electric by rubbing, which property it 
 retains for half an hour ; its specific gravity is 3, 5—3, 6 ; it does not 
 alter before the blowpipe; it burns however at a high degree of heat, 
 and in atmospheric air with a bluish flame ; its touch is very cold; 
 it consists of carbon. The Diamond bears the same name in trade, 
 but is changed according to its cut: the blackish and brownish 
 Diamonds are called the Savoy Diamonds (Diamand Savayards.) The 
 original bed of the Diamond is not yet known, and the opinions are 
 much divided : in the East Indies we find it in a conglomerate of 
 sandstone, consisting of quartz grains, and disintegrated by the fer¬ 
 ruginous sand ; and in the mountain chain Ralla-Malla, in Hindostan, 
 between the 95° and 98° E. L. Some of the most celebrated Diamond 
 mines consist of a Breccia from argillacious slate, quartz, lime and 
 sandstone; the Boulters and the sand of desserts and rivers yield 
 Diamonds mostly rounded or in granular form. The richest Diamond 
 mines are: Roalcorda, at the junction of the rivers Bimah and 
 Ristna; Golconda, along the shore of the Pennar, Sumbhulpra; 
 Bundelkened, in the neighbourhood of Pannah, where one thousand 
 labourers are kept employed. Yisapur, Hydrabad, &c., on the Island 
 of Borneo, yield likewise Diamonds; and, according to Jameson, 
 Diamonds were found in the Indies in the coal formation. 
 
 In Brazil, they were discovered in 1728, by chance, having pre¬ 
 viously been always thrown aside with the flint and other refuse ob¬ 
 tained by the washings of gold, until an inhabitant, who had some 
 knowledge of rough Diamonds, collected a large parcel and carried 
 them to Portugal, and acquired by its sale a large fortune. Another, 
 who was informed of the operations of the first, shared an equally 
 good luck. The government’s attention was drawn to it, and de¬ 
 clared, in 1730, that all Diamonds found there belong to the crown. 
 
 Diamonds are found in the Talcose Chlorite Shiste, and in a 
 Breccia, consisting of ferruginious clay, quartz pebbles, sand, and 
 oxide of iron fragments; and are found in a secondary bed, 
 accompanied by gold, platina, topaz, beryl, chrysoberyl, or tourmaline. 
 They are found particularly in the valley of Sejues, along the rivers 
 Jequetinhonha and Pardo, which run into the Diamond district; 
 these carry most Diamonds by. The dykes and brooks of the district 
 contain more or less rich Diamonds, which are found there in recent 
 and older beds. Beyond the diamond district, the Diamond is likewise 
 found in the province of Minas Geraes, on the Serro de St. Antonio, 
 
54 
 
 TREATISE ON GEMS. 
 
 in the Serro Frio and in the livers Aboite, Andaja, da Saneno, da 
 Prata, and in several other places. 
 
 In Russia, the first Diamond was discovered in July, 1829, by 
 Humboldt and Rose, when on their iourney to Siberia, on the west 
 side of the Uralian mountains, in the gold washing establishments of 
 Krestowosdwisheaski, belonging to Count Schuwalow. The locality, 
 in connection with the other circumstances of the place where the 
 Diamond was found, bears a striking resemblance to the Diamond 
 district of Brazil. The predominating rock of the spot on the Uralian 
 mountains is a quarzose chlorite, talcose sliiste (ita columnite) with 
 an admixture of iron pyrites and mica, and wherein we find beds of 
 red oxide of iron, talcose sliiste, limestone and dolomite. In the val¬ 
 ley of Poludenka and Aedephskoi the Diamonds are found in the 
 debris of the mountains, accompanied by quartz, ita columnite, brown 
 hematite, talcose slate, dolomite, chalcedony, anatas. gold, or platina; 
 it is not yet decided to what formation this rock originally belongs. 
 The production of the Diamond is two-fold ; either they are dug out 
 from the earth, or they are collected in the sand of the rivers. If by 
 the latter way, they are more or less rounded, wedged and rubbed off: 
 whereas the former appear coated with an earthy, pale gray, yellow or 
 rose-red ; rarely, however, with a blue or green crust. Many valua¬ 
 ble mines have been relinquished in the East Indies since the discove¬ 
 ry of the Diamonds in Brazil. The locality of the finest Diamonds 
 is at present the neighbourhood of Sumbhulpore. Two tribes, called 
 the Tliata and Tora, living in sixteen villages, occupy themselves 
 particularly with searching for Diamonds, beginning in the month of 
 November, till the beginning of the rain time, particularly in the bed 
 of the Mahanudi on its left shore, where some other small rivers, 
 Maund, Reloo, Eeb, &c., pour into the same. Four or five hundred in 
 number, consisting of men, women and children, are examining 
 continually all the spots of the river from Cauderpoor to Longpoor, 
 a distance of about 120 miles, till the stream is impeded by the rocks; 
 and likewise all excavations or other cavities of the beds where any 
 alluvial deposites may be traced. All their implements consist in 
 a pickaxe (ankova), in a board of five feet long, excavated three 
 inches in the middle, but provided with its border (daer) and in a 
 smaller similar impliment, called by them kootla, but both of the 
 shape of a shovel. The process is very simple: they first dig the 
 earth with the axe and let it accumulate in heaps along the shore; 
 the women afterwards take it on their large shovels and allow the 
 water to run over the earth; they then pick the flints and coarse 
 
TREATISE ON GEMS. 
 
 55 
 
 gravel out of it, and bring the residue on the smaller shovels, spread¬ 
 ing it out, and examining it very carefully, separating from it the 
 Diamonds and grains of gold. Another method pursued in the East 
 Indies is to surround a small plain, where the Diamonds are expected 
 to be found, with a wall of two feet high, under which, however, 
 water is permitted to run by several openings ; and after having 
 thrown a good deal of earth within the wall, and the water passed 
 through two or three times, the larger stones are picked out and the 
 residue dried, and the Diamonds selected as before. 
 
 The washing establishments of the Diamond in Brazil, particu¬ 
 larly in the celebrated district Tejuco, on the Rio San Francisco and its 
 adjoining smaller rivers, are conducted in the following manner :— 
 
 In order to get at the bottom, or soil, of the river, means are used 
 for leading the water at a certain spot to a different direction, and 
 then that bed of the river is allowed to dry out, and the sediment 
 found, consisting of a conglomerate of quartz pebbles, kept together by 
 oxide of iron, is brought to one place for washing it out. It is a large 
 bench of triangular form, so as to keep from twenty to thirty negroes 
 busy: in the middle of this bench is a gutter, to which is connected 
 a trough, all inclined somewhat, in order that the water may run 
 down voluntarily, but which may be stopped by putting loam at the 
 end; and another gutter, with a trough, is joined further down. The 
 negro, who has collected in the dry season a large quantity of the 
 sediment, is occupied in the rainy season in putting from fifteen to 
 eighteen pounds at the time in the trough, spreading it there and 
 allowing so much water to run over it, until it runs off quite clear 
 from the lower trough, but at the same time keeping the trough con¬ 
 tinually moving. He begins then to pick out the larger stones from 
 the earthy part, and then the smaller stones, until he comes to such 
 grains, fully suitable to pick the smallest particles, which he examines 
 with the greatest care, on account of the Diamonds. As soon as a 
 negro has found a Diamond, he must make it known by clapping his 
 hands, and the surveyor, who is seated on an elevated chair around 
 the bench, takes the same and deposites it in a dish filled with water, 
 and in which all the Diamonds found during the day, are collected. 
 They are then delivered over to the superintendant, who counts and 
 weighs them, and enters them, with other particulars, in a book kept 
 for that purpose: he keeps them together in a bag, until he delivers 
 them, which he does twice a week, to the government, at Tejuco. 
 
 Every superintendant has to live in the neighbourhood of the prin- 
 ciplal washing establishments, which were formerly leased for a cer- 
 
56 
 
 TREATISE ON GEMS. 
 
 tain sum by the government; but the impositions practised were so 
 great that she took the superintendance upon her own account in 
 1772, and has guarded the diamond districts along their lines by 
 strong sentinels, who will not allow strangers to pass through without 
 the permission of the general superintendant; and even the inhabi¬ 
 tants, when crossing the line of the diamond districts, have to procure 
 written permissions from the above authority; and every body must, 
 on leaving the district, submit, without any dispensation, to a personal 
 and strict examination and search by the soldiers; and foot passen¬ 
 gers are always arrested by sentinels and spies continually on the 
 alert. St. Antonio de Tejuco, forty leagues from Villa Rica, is the 
 capital of the Diamond district, and the seat of the superintendence 
 of the Junta Diamontina, consisting besides, of a confiskal, two 
 cashiers, one inspector-general and a book-keeper. All the procured 
 Diamonds are delivered up yearly, to the government, at Rio 
 Janeiro. 
 
 From four to five thousand negroes were engaged in the years 
 1772 to 1775 ; and in the year 1818 but one thousand: among them 
 were the feitores or surveyors, one hundred in number, in the latter 
 year ; likewise ten superintendants, whose business it is to conduct 
 the mining department and the collection of the Diamonds. 
 
 In order to encourage the negroes, presents of tobacco, cloth, &c., 
 are awarded, according to the price of the Diamonds which they find; 
 and the one who finds, for instance, an Eighth (17 carats and 2 
 grains) receives his total liberty; but they are severely punished for 
 any offence, and if repeated, are not allowed to be at this work. 
 Notwithstanding the most watchful and scrutinous rules and attention 
 of all the officers, the fraud with stolen Diamonds is very considerable; 
 and it is estimated that the smuggling amounts to one-third of the 
 whole income. The smugglers, who are runaway slaves, examine 
 the most remote parts of the district, or steal the Diamonds at night 
 from the working establishments; others, again, who understand it, 
 will take the stolen Diamonds from the negroes, and devise means of 
 escaping with them, either in the soles of their boots, or in hollow 
 canes, &c.; and it is a remarkable fact, that all Diamonds obtained 
 from the smugglers are invariably larger and more beautiful than 
 those which are brought into market by the government. The 
 thieves practice all manners of tricks and impositions, even in the 
 presence of the surveyors : for instance, they conceal the good 
 Diamonds, during the washing hours, between the fingers, the toes, 
 in the ears, in the mouth or in the hair : they also throw them away 
 
TREATISE ON GEMS, 
 
 57 
 
 with other stones, in order to pick them up in the night; they often 
 even swallow them. 
 
 The soldier, arresting any smuggler, receives a reward ; the property 
 of the latter is confiscated, and he is sent to Angola, as a prisoner, 
 for upwards of ten years. 
 
 The pure transparent Diamond, which is cut in the different 
 forms already mentioned, looses generally one-third to one-half of its 
 original weight by this operation. 
 
 In purchasing rough Diamonds, every precaution ought to be used 
 to prevent getting false Diamonds instead of real ones, and faulty ones 
 instead of pure Diamonds. The officers of the Junta Diamontina test 
 the rough stones by holding them, in rubbing together, close to the 
 ear, and listen to the tune produced by it, which gives them sufficient 
 satisfaction of their being genuine, as it is only to be observed in real 
 Diamonds. It requires, however, considerable practice for distinguish¬ 
 ing with accuracy this test. Strangers particularly, are imposed upon 
 by the negroes in Brazil, by purchasing from them gems cut and 
 polished with the facets, resembling those of the Diamond; and 
 although any one acquainted with the Diamond will soon detect the 
 imposition by the want of specific weight, the peculiar lustre, fire and 
 hardness, it requires to be on his guard. If, however, the Diamond is 
 ascertained to be genuine, we have to look particularly after its purity, 
 colour, form, and size, which are the conditions for the price of a 
 rough Diamond. 
 
 It requires considerable experience to determine from a rough 
 Diamond whether any of its faults are at the surface or in the interior, 
 whereby, often, the Diamond, in removing all its faults, may be 
 diminished to half its size. We often, however, judge the rough 
 stones by their colour; those turning towards the green colour are 
 considered to be the best; those of a reddish colour to be good stones; 
 the black colour indicates a hard stone ; and we judge a yellowish 
 or grayish colour as making bad Diamonds. The natural form 
 of a Diamond likewise gives a characteristic to the purchaser of 
 rough stones; for a flat, thin, or triangular stone would loose much 
 in the grinding, and not be so high as to give it sufficient fire ; and 
 likewise we are not sure of the result of the cutting, and the hemi- 
 trope crystals are very difficult to work. The best forms of Diamonds 
 for cutting are the octahedron, which is principally found in the East 
 Indies, and is called Pint by the diamond-grinders, and the rhombic 
 dodecahedron, which is found principally in Brazil; cheese-stones are 
 the names of amorphe Diamonds, given by the diamond grinders. 
 
 H 
 
58 
 
 TREATISE ON GEMS. 
 
 According to the quality of the Diamonds they are divided in 
 Sumbhulpur into four classes, which are corresponding with the 
 deities of the Hindoos; the Bramins, Tschettri, Wassiers (Bysh) 
 and Tschadrie. The native jewellers are very expert in estimating 
 the value of these Diamonds. 
 
 The value of the polished Diamonds is depending on the following 
 conditions: 
 
 1st, The Colour. The limpid Diamonds command the highest 
 price, and twice as much as those that are coloured; the blackish, 
 brownish, yellowish, brown, steel-gray, and impure blueish ones, stand 
 in no value, and are often rejected for working. 
 
 2d, The Purity , Faultlessness and Transparency. The 
 Diamonds ought to be, according to the technical terms of the jewel¬ 
 ers, free from ashes, gray spots, rusty or knotty places, veins, fissures, 
 scratches, feathers, flaws, sand, grains, and of faint yellow or vitreous 
 spots. The Brazilian Diamonds exhibit, sometimes, in their interior, 
 designs resembling mosses, like those of the Mocha stones and agates ; 
 and we may often observe it in the green Diamond; if a limpid 
 Diamond plays somewhat in the brown colour, it is called shrugging , 
 and diminishes its value: paunched , are those Diamonds which are 
 neither pure nor clear. 
 
 The transparency and clearness of the Diamond is divided into 
 three classes, viz :— 
 
 A, of the first water , are those Diamonds which are free of the 
 slightest faults whatever, and stand highest in price. 
 
 B, of the second water , are those Diamonds which, although clear 
 and limpid, possess some dark spots, clouds, or flaws. 
 
 G, of the third water , are those Diamonds possessing a gray, brown, 
 yellow, green, blue, or blackish colour ; or they are limpid, but possess 
 several material faults. 
 
 In order to determine accurately the Diamond, it is well to breathe 
 on them, whereby they loose, for a moment, their lustre, and the eye 
 is then better enabled to examine them and distinguish their faults. 
 The real Diamond becomes clear much sooner than the false. 
 
 3d, The Cut. The perfect and regular cut of the Diamond increases 
 its value considerably; a Brilliant, for instance, of one carat, is 
 worth twice as much as a rough Diamond of equal weight. It 
 depends upon the proportions of the height to the circumference of 
 the Diamond, and that the planes and faces stand in a regular pro¬ 
 portion, for should this not be the case, the Diamond would loose 
 much of its fire. Likewise the form of the Diamond influences the 
 
TREATISE ON GEMS. 
 
 59 
 
 price. A Brilliant is dearer than the Rose Diamond, and this again 
 is dearer than the thick and tablestone. Likewise the faces of the 
 Brilliant influence the price: once cut, is a Brilliant that possesses no 
 cross facets on the lower part of the stone: twice cut if there is one 
 row of facets on the collet-side; thrice cut, if the Brilliant possesses 
 the facets on the bizel and collet-side, according to the rule of cutting. 
 The more rows of facets a Brilliant displays the higher price is put 
 upon it. 
 
 4th, The Size and Weight. The price of a Diamond depends 
 considerably upon its size; those Diamonds of great splendour and 
 size are called Paragons or Nonpareils, the Ne Plus Ultra ; and the 
 other less weighty ones according to their actual weight. The 
 weight employed in Sumbhulpur is the rutta and masha. Seven 
 rutts is equal to one mash, and one rutt is equal to two grains. In 
 Brazil the weight is specified by carats (quilates.) Seventeen and a 
 half quilates are equal to one dram (octava); thirty-two vintenes are 
 equal to seventy grains (graos); one carat is equal to four grains. 
 
 The price of Diamonds is determined in trade by examining accu¬ 
 rately their character as above stated, and then the price is fixed: 
 the weight of the Diamond is at first multiplied by itself, and the 
 sum obtained multiplied again with the price of one carat. A Bril¬ 
 liant, for instance, would weigh two carats, and on examining its 
 properties, its price would be found to be forty-four francs. We pro¬ 
 ceed in the following manner for getting at the total value of the 
 Diamond 2x2x44=176 francs. We do not always, however, 
 arrive at the correct result. If the Brilliants are very large, and 
 exceed the weight of 8 or 10 carats, it is difficult to arrive at a 
 standard. I will endeavour to give below a table of the prices of the 
 Diamond in Holland, France, England, and Germany, as far as ascer¬ 
 tained, and as near to the actual price current as I could be informed. 
 
 Rough Diamonds fit for cutting, are worth ten or twelve francs per 
 carat: any Diamond exceeding the weight of one carat is estimated 
 by the square of its weight multiplied with eleven or twelve francs as 
 the average price. 
 
 For a Brilliant of one carat and first water, the value in Germany 
 i s forty-four francs; of the second w T ater, twenty eight francs. 
 
 Rose Diamonds of first water and one carat 20 francs. 
 
 “ “ second, “ 13 “ 
 
 Tablestone, - - - 14 
 
 Brilliants, 30 to 35 pieces to the carat 22 
 
 20 “ “ “ 40 “ 
 
60 
 
 Brilliants, 10 
 
 TREATISE ON GEMS. 
 
 pieces to a carat 
 
 k 
 
 38 
 
 francs. 
 
 
 5 
 
 cc cc 
 
 cc 
 
 35 
 
 CC 
 
 
 4 
 
 cc cc 
 
 cc 
 
 36 
 
 CC 
 
 Brilliants of three grains are in much demand, and are worth fifty 
 francs per carat. Those of three carats, used for centre-pieces in 
 necklaces, are sometimes worth four hundred francs. Rose Diamonds 
 for mounting, and forty to the carat, are worth twenty francs the 
 carat; if a little larger, thirty-five francs per carat. 
 
 Diamonds unfit for cutting, and used by glass-cutters or glaziers, 
 are worth from ten to fifteen francs per carat, and still smaller ones are 
 worth less; they are now employed by the lithographers for then- 
 engravings and etchings. 
 
 According to Netot, Pujoux, and Lucas, the price of the Diamonds 
 of the first water, were three hundred francs per carat, and second 
 water, one hundred and fifty. 
 
 Diamonds of one grain and less 96 francs per carat. 
 
 The double cut, first water, 
 
 125 
 
 CC 
 
 cc 
 
 cc cc 
 
 6 to a grain, 
 
 150 
 
 cc 
 
 cc 
 
 Of 2 grains, 
 
 - 
 
 170 
 
 cc 
 
 cc 
 
 Of 3 grains, 
 
 - 
 
 200 
 
 cc 
 
 cc 
 
 Of one carat, 
 
 - 260 to 2S0 
 
 cc 
 
 cc 
 
 A Diamond of 6 grains, 
 
 600 
 
 cc 
 
 cc 
 
 CC 
 
 8 “ - 
 
 1000 
 
 cc 
 
 cc 
 
 CC 
 
 10 “ - 
 
 1400 
 
 cc 
 
 cc 
 
 cc 
 
 12 <• - 
 
 1800 
 
 cc 
 
 cc 
 
 cc 
 
 15 « - 
 
 2400 
 
 cc 
 
 cc 
 
 cc 
 
 18 “ - 
 
 3500 
 
 cc 
 
 cc 
 
 u of 6 carats - 5000 francs per carat. 
 
 The above prices are from Brards Mineralogie appliquee aux Arts. 
 
 A great sale of Diamonds took place in tire summer of 1837, at the 
 auction of Randell and Briggs, London, a report of which is curious 
 as exhibiting the facetious and extrinsic value of these costly gewgaws. 
 There were twenty-four lots which produced forty-jive thousand eight 
 hundred and eighteen founds —nearly two hundred and twenty- 
 nine thousand dollars ! I Some of the prices were as follows:— 
 The celebrated Nassauck Diamond, which weighs three hundred fifty 
 seven and a half grains, and is of the purest water, was purchased for 
 thirty-six thousand dollars. It is considered to have fetched a price 
 considerably under its value. A magnificent pair of brilliant ear¬ 
 rings, weighing two hundred twenty-three and a half grains, formerly 
 the property of Queen Charlotte, were bought for fifty-five thousand 
 
TREATISE ON GEMS. 
 
 61 
 
 dollars, a price infinitely below their usually estimated value. A 
 sapphire, seventy-five and a half carats, set with brilliants for a brooch, 
 two thousand four hundred and sixty-five dollars. Brilliant ear-rings, 
 three thousand seven hundred and fifty dollars. A brilliant necklace, 
 four thousand three hundred dollars. Drop emerald ear-rings, two 
 thousand three hundred and twenty-five dollars. Brilliant ear-rings, 
 four thousand two hundred and fifty dollars. A Turkish dagger, 
 mounted with brilliants and rubies, four thousand dollars. A single 
 brilliant, eight hundred dollars. A brilliant drop, seventy-nine and a 
 half grains, five thousand nine hundred dollars. An oblong brilliant, 
 one hundred fifty-one and a quarter grains, fourteen thousand dollars. 
 A brilliant necklace, eight thousand dollars. Brilliant ear-rings, twelve 
 thousand five hundred dollars. Brilliant necklace, twelve thousand 
 five hundred dollars. Brilliant drops, formerly belonging to Maria 
 Antoinette, eight thousand eight hundred and seventy-five dollars. A 
 rose Diamond, eight thousand five hundred. A brilliant drop, ten 
 thousand five hundred. A round brilliant, seventeen thousand five 
 hundred dollars. A lozenge brilliant, three thousand five hundred 
 dollars, etc. etc. 
 
 On comparison with prices now in market, it is certain it has much 
 declined, partly on account of the immense stock which has been 
 brought from their native locality. According to Spix and Martius, 
 there have been produced in Brazil, from 1772 to 1818, 1,298,037 
 carats Diamonds, that is in the time of the Royal Administration ; but 
 that during the Lease, only 1,700,000 carats were produced, which 
 together make 2,998,037 carats, or 1301 1-4 pounds; thus averaging 
 from fourteen to fifteen pounds per year ; those brought into market by 
 contraband being excepted. The value of the above Diamonds, 
 (8,000 reis per carat,) produced in Brazil, amounts to 23,984,276,000 
 reis, or about 40,000,000 francs; this sum bears no comparison to the 
 expenses of producing them, since the government lately paid forty 
 francs, fifty cent, per carat, whereas they only yielded from eighteen to 
 nineteen francs. On this account, the administration at Rio de Janeiro 
 has been induced to leave the mines to private individuals. Owing 
 to this decrease in the production, the number of labourers are reduced. 
 The richest production was in 1784, when fifty-six thousand one 
 hundred and forty-five carats were washed out, and the poorest in 
 1818, when they procured nine thousand three hundred and ninety- 
 six carats. In Brazil, large Diamonds are much rarer than in the 
 East Indies, where they are in general of much better quality than 
 in Brazil. In the latter country, from 1772 to 1811, they found but 
 
62 
 
 TREATISE ON GEMS. 
 
 thirty-six Diamonds weighing upwards of seventeen carats, and from 
 1812 to 1818, but eighty-three Diamonds weighing over eight carats. 
 In the East Indies, according to Breton, from the year 1804 to 
 1818, there were found in Mahanues twenty large Diamonds, the 
 aggregate weight of which amounted to four hundred and thirty-six 
 carats and one grain. The largest was found in 1809, and weighed 
 six hundred and seventy-two grains, but of the third water; another 
 of three hundred and eight grains, and another of two hundred and 
 eighty-eight grains. 
 
 As it has already been stated that the artist and amateur have to 
 be on their guard against imposition in the purchase of Diamonds, 
 it may be well to state that there is the one-half brilliant, having the 
 form of a brilliant above (the upper pyramid) and have no lower 
 pyramid; or another stone is pasted on by means of mastic. The 
 character of the stone is readily detected when taken out of the 
 mounting. 
 
 Or Sapphires, Hyacinths and Topazes are sometimes slightly cal¬ 
 cined and sold for Diamonds. The first two are heavier than the 
 Diamond; they are, however, harder, and possess more fire. The 
 Topaz is distinguished by its property to become electric when heated. 
 
 And Rockcrystal is much lighter, but brilliant and hard; and the 
 same character is applicable to the Strass. 
 
 1 The following list shows the size and weight of the most interesting 
 Diamonds in the possession of different sovereigns. 
 
 I. The largest Diamond is in the possession of the Grand Mogul, 
 and according to Tavernier, resembles in form and size half a hen’s 
 egg. Its weight is two hundred and ninety-seven and three-six¬ 
 teenths carats. It was found in 1552, in the mine of Colore, a short 
 distance to the east of Golconda, and is valued at four millions francs. 
 It is cut as a Rose Diamond, and is perfectly limpid, except a small 
 flaw at the end of the girdle. 
 
 II. The Diamond in the possession of the Rajah of Mattan, in 
 Borneo, weighs three hundred and sixty-seven carats: and it was 
 found on that island. It is of an egg form, has a cavity towards the 
 thinner end, and is of the first water. 
 
 III. The Diamond belonging formerly to Nadir Shah, Sultan of 
 Persia, and now in the possession of the Russian crown, weighs one 
 hundred ninety four and three-fourths carats. It is of the first water, 
 without flaws or faults of any kind. Its form is that of a flattened 
 oval, about the size of a pigeon’s egg, cut in a pyramidal form; is 
 one inch three lines in diameter, and ten lines high. It was purchased 
 
TREATISE ON GEMS. 
 
 63 
 
 by the Empress Catharine for about ninety thousand pounds, cash, 
 and an annuity of four thousand pounds, but is considered of more 
 value. 
 
 IV. The Diamond in the treasury of Rio Janeiro was found in 
 1771, at Rio Abaite, by three criminals, who delivered it to the 
 government, for which they were pardoned. It weighs one hundred 
 and thirty-eight and a half carats. 
 
 V. The Austrian Crown possesses a Diamond which weighs one 
 hundred and thirty-nine and a half carats, and is valued at one 
 hundred and nine thousand two hundred and fifty pounds. It is 
 beautiful and well formed, but its colours turn towards the yellow. 
 
 There is another Diamond belonging to the crown, which was 
 formerly in the possession of Charles the Bold, of Burgundy, who 
 lost his all in the battle of Granson, and likewise this Diamond, 
 which was at that time the largest in Europe. A Swiss soldier, who 
 was the robber of the Diamond, sold it for a crown dollar to a priest; 
 and, after passing through several hands, was purchased by Pope 
 Julian II, for twenty thousand ducats. 
 
 VI. The Regent or Pitt Diamond, now belonging to the crown of 
 France, is said to have been found in Malacca, and was purchased 
 by Mr. Pitt, then Governor of Bencoolen, in Sumatra, and sold by 
 him to the Regent Duke of Orleans, by which it was placed among 
 the crown jewels of France. It weighs one hundred and thirty-six 
 and three-quarters carats; is cut in the form of a brilliant, and is of 
 the first water, being absolutely faultless. When rough it weighed 
 four hundred and ten carats, took two years labour for cutting, and 
 is worth, according to the value put by a commission of jewellers, in 
 1791, twelve millions of livres. 
 
 VII. Another Diamond, the Sancy, one of the largest and most 
 
 beautifully coloured, likewise belongs to the crown jewels of France. 
 It is of a pear form, cut as a double Rose Diamond and weighs one 
 hundred and six carats. It was bought for six hundred thousand 
 livres. 4 
 
 VIII. Another Diamond, belonging to the crown jewels of France, 
 is of a rich sky-blue. It weighs sixty-seven and an eighth carats, 
 and is valued at three millions of livres. 
 
 IX. A rough Diamond found in the river Abatio, in Brazil, is in 
 the possession of the Prince Regent of Portugal, which weighs an 
 ounce troy. 
 
 X. The two large Diamonds belonging to the Shah of Persia have 
 already been mentioned in the first part, with accompanying figures. 
 
64 
 
 TREATISE ON GEMS. 
 
 XL The Turquish crown has two very large Diamonds; one of 
 eighty-four carats, and the other of one hundred and fourty-seven 
 carats. The latter is estimated at eighty thousand ducats. 
 
 XIL A Diamond found in Brazil, in 1780, weighs seventy-two 
 carats and three-fourths grains. Another, found in 1803, weighs 
 seventy carats. They are both at Rio Janeiro. 
 
 XIII. The largest of all known Diamonds is said to be in the 
 possession of the king of Portugal. It was found in Brazil, in the 
 Diamond District, and is as yet in its rough state. It is of the size 
 of a chicken’s egg, weighing one thousand six hundred and eighty 
 carats (above eleven ounces); and is estimated at fifty-seven million 
 pounds sterling. This is now believed to be a white Topaz, on the 
 general opinion of jewellers and mineralogists. 
 
 2. CORUNDUM. 
 
 The above name was applied to a different species from that of 
 Sapphire; but these terms are now generally acknowledged as syno¬ 
 nymous ; not so, however, the emery, which does not belong to this 
 species. 
 
 Both occur in rhomboids, often too in crystals of secondary form. 
 They scracth all other gems except the Diamond. Their streak 
 and powder are white; and the specific gravity is 3,9—4. They 
 acquire electricity by rubbing, which is retained for several hours. 
 They are not fusible before the blowpipe. With difficulty, by means 
 of borax, they form a clear limpid glass. Acids have no effect on 
 them. Their chemical constituents are alumine, silica and oxide 
 of iron. 
 
 A sapphire. This name is derived, probably, from the Hebrew, 
 as it is often mentioned in the Bible. It is not certain whether the 
 ancients understood merely the blue variety of this gem, and at 
 the same time be ignorant of other blue stones, such as Lasulite, 
 Fluorspar, &c. It was not used by them as a gem, probably on 
 account of the difficulty in working it; but as a medicine, many 
 peculiar virtues were ascribed to it. This species has hitherto been 
 usually divided by means of its different colours. The name of 
 Ruby has reference to a red colour, and was applied by the ancients 
 
 I have been informed by Mr. Featherstonehaugh, the U. S. Geologist, that he has 
 discovered perfect crystalized Diamonds (a green and a white) south of the Potomac ; 
 and Mr. Thomas G. Clemson, of Philadelphia, kindly exhibited to me his Diamond, 
 found in North Carolina, weighing one and a half carats, with distinct octahedral 
 form. 
 
TREATISE ON GEMS. 
 
 65 
 
 to the Carbuncle. Sapphire occurs in crystals, in rounded grains and 
 pebbles. It is generally transparent; but sometimes only translu¬ 
 cent, or displaying a shine of light of six rays, resembling the form 
 of a star. It possessess double refraction in a slight degree, and a 
 vivid vitreous lustre, which sometimes turns to that of mother of 
 pearl. Its fracture is from conchoidel to uneven. Its principal 
 colours are the blue and red, with their various shadings ; sometimes 
 white, grey, yellow, green, brownish-green, and black. 
 
 If the red Sapphire (Ruby) is exposed to a great heat, it becomes 
 green, but when cold returns to its original colour : the green Sapphire 
 undergoes no changes. 
 
 The various names given to Sapphire, according to its colour are: 
 
 1st. Ruby, (oriental Ruby) of a dark crimson-red, cochineal or 
 carmine, and rose-red mostly inclining to the violet-blue. 
 
 a. Oriental Hyacinth, aurora-red. 
 
 2d. Oriental Amethyst, paleish violet-blue. Playing sometimes in 
 rose and purple-red, like the common Amethyst, except in its superior 
 lustre. 
 
 3d. White Sapphire, limpid and perfectly transparent; vivid lustre, 
 resembling the Diamond. 
 
 4th. Sapphire, Oriental Sapphire, from the darkest to the lightest 
 blue with different shadings, whence it is denominated by different 
 terms, such as Male Sapphire, of a perfectly blue and clear Berlin 
 or Smalts blue; Female-Blue , full blue, with a tinge of white; 
 sometimes sky-blue, with streaks or specks. Water Sapphire, very 
 pale-blue, and sometimes discoloured. Cat-Sapphire , blackish or 
 greenish-blue, often not transparent. 
 
 5th. Oriental Topaz; lightly yellow, lemon or brownish straw- 
 yellow ; sometimes playing in the green colour; it is distinguished 
 from the common or Proper Topaz by colour and lustre; but it occurs 
 likewise much larger, and seldom less free from faults than any other 
 species of Sapphire. 
 
 6th. Oriental Aquamarine; greenish blue, pure and transparent; 
 possessing a higher lustre and greater hardness than the common 
 Aquamarine. 
 
 7th. Oriental Chrysolite, or Peridote; yellowish-green, resembling 
 in colour the Chrysoberyl, but may be distinguished from it by its 
 higher lustre. 
 
 8th. Oriental Emerald ; green, more or less dark, inclining to 
 yellow; it does not equal in colour the real emerald, but possesses 
 a higher lustre, and is at the same time very rare. 
 
 i 
 
6G 
 
 TREATISE ON GEMS. 
 
 The Sapphires which sometime displays a peculiar play of light, 
 are divided into :— 
 
 1st, Star-Sapphire (Asteria, Opalescent, or Chatoyant Sapphire). 
 Some translucent Sapphires display, if held before the light of the 
 sun or burning taper, a white shine, running in six rays, resembling 
 three white planes, or stripes crossing themselves in one point. This 
 property is thus visible when the Sapphire is cut convex (or cabouchon) 
 and when the principal axis of the crystal stands perpendicular on 
 the base of the convex cut stone ; these Star-Sapphires are either 
 called Ruby Asteria, Sapphire Asteria, or Topaz Asteria, according 
 to the colour it bears. 
 
 2d, Girasol-Sapphire, Oriental-Girasol, Sunstone, Sapphire, or Ruby 
 cat’s-eye are of a yellowish, reddish, or bluish shine, or reflection of 
 light, generally of a lighter colour than the stone itself, displayed 
 when moved or turned on the convex surface. The different varieties 
 of Sapphires are found in the sand of rivers, or in boulders, with 
 Garnets, Zircons, and other gems, in Ceylon, China, Siam, Brazil, 
 Bohemia, France, Saxony and the United States. It has been 
 observed that the blue Sapphires are frequent in Ceylon and not 
 the Rubys; and that in Pegu it is the reverse. We also find the 
 Sapphire in Basalt. The most celebrated mines of Sapphire are at 
 Mo-gaot and Kyat-Pyan, five days journey from Ava. The Boa, or 
 Emperor of the Birmans, retains all the larger Sapphires. 
 
 For the cutting of a Sapphire an iron mill is used, and for polish¬ 
 ing, a copper mill, or of an alloy of lead and tin, to which a horizontal 
 motion is given by very simple machinery; its surface is charged 
 with Diamond powder and oil, or with fine emery and water. A 
 thick peg or guage of wood, pierced with small holes in all directions, 
 is set upright on the lapidary’s bench, close to the mill. The stone, 
 being placed on the surface of the mill, the opposite end of the stick 
 to which it is cemented, being inserted in one of the holes of the 
 guage, the mill is put in motion by turning a winch, and the stone 
 kept steady on it. 
 
 When the stone has all the facets, the cutting mill is taken out 
 and replaced by one of brass, on which the polishing is performed by 
 means of fine emery and rottenstone, in the same manner as before. 
 A good judgment is required in determining the form and proportions 
 best adapted to set off any particular stone to the best advantage. If 
 the colour is full and rich, its transparency perfect, and its refractive 
 power considerable, the best form to give it is the brilliant. If, on 
 the contrary, the colour is dilute, the most advantageous method of 
 
TREATISE ON GEMS. 
 
 67 
 
 cutting it is to cut the table side (pavillion) brilliant fashion, and the 
 collet side (culasse) in steps; by this means the table itself will be 
 left dark, while all the light reflected from the steps on the under side 
 of the stone will be thrown up into the facets, by which the table is 
 surrounded. The French lapidaries cut the most perfect Sapphires 
 in a square or octagon form, with a single delicate step between the 
 table and the girdle, and three or four steps between the girdle and 
 the collet. 
 
 If the Sapphires possess a varying chatoyant lustre, or are of a 
 small size, their form is always hemispherical or elliptical, without 
 any flat facets ; the flatter the ellipse, the more the varying lustre is 
 diffused over the surface of the stone ; whereas with a high ellipse it 
 is condensed on a single spot. 
 
 In setting Sapphires, we always use foil answering to their colour. 
 The Ruby is set with a reddish gold foil, or a foil of copper or red 
 glass: the blue Sapphire with a silver foil, or blue-coloured foil, or with 
 feathers of blue ducks, pigeons, or peacocks, and the water Sapphire 
 in a black back; but all perfectly pure Sapphires are set a jour. 
 
 Many Sapphires may be deprived of their specks by a careful cal¬ 
 cination in a crucible filled with ashes or clay, and they assume then 
 a more agreeable and purer colour and greater transparency. 
 
 The Sapphires are very favourite gems, and are extensively used by 
 jewellers for setting pins, rings &c. In China the ladies’ slippers are 
 mounted with Rubies. 
 
 The blue Sapphire has of late been employed as lenses for micro¬ 
 scopes with great success. According to Brewster, it is, for its refract¬ 
 ing power, second only to the Diamond, and superior to all other gems. 
 A new use has lately been made of the Sapphire for drawing wires, 
 it being cut in the form of a wedge, through which, by means of a 
 Diamond-point, a circular hole is drilled and then fastened on a brass- 
 plate ; the wire is then drawn through the narrow aperture of the Sap¬ 
 phire towards the wider, by which process it is reduced to a thinness 
 never otherwise attained. 
 
 The price of Sapphires is very relative, but their proportional value 
 is placed next to the Diamond. The Oriental Ruby stands highest 
 in value, and when perfect, and exceeding three carats, is generally 
 as dear as a Diamond of equal weight and quality. After the Ruby, 
 blue Sapphire stands next in value; and as this is not so rare, and 
 occurs in larger specimens, it is not so high in price. Some put the 
 price of the blue Sapphire equal to that of the coloured Diamonds. 
 Others put the price at half that of a Brilliant under similar circum- 
 
68 
 
 TREATISE ON GEMS. 
 
 stances. Sometimes the value is fixed by multiplying half the price 
 of a Sapphire weighing a carat, with the square of its weight. It is 
 therefore very difficult to come at an exact price current; and the 
 following average prices come nearest to their commercial value. 
 
 
 RUBY. 
 
 
 
 
 Of 1 grain weight - ■ 
 
 
 
 - - 2 francs. 
 
 2 “ “ - - 
 
 
 
 - - 5 
 
 U 
 
 3 “ “ 
 
 
 
 - - 12 
 
 U 
 
 1 carat “ - - 
 
 
 
 - 20 
 
 U 
 
 2 “ - - - - 
 
 
 
 - 60 
 
 U 
 
 3 “ - - - - 
 
 
 
 - 150 
 
 U 
 
 4 “ ... - 
 
 
 
 - 250 
 
 U 
 
 5 “ - - - - 
 
 
 
 - 350 
 
 u 
 
 BLUE 
 
 SAPPHIRE. 
 
 
 
 1 carat - - - - 
 
 
 
 - 10 francs. 
 
 2 “ - - - - 
 
 
 
 - 20 
 
 u 
 
 3 “ - - - - 
 
 
 
 - 30 
 
 u 
 
 4 o _ . . 
 
 
 
 - 45 
 
 u 
 
 5 “ --- - 
 
 
 
 - 60 
 
 u 
 
 6 “ - - - - 
 
 
 
 - 80 
 
 u 
 
 8 “ - - - - 
 
 
 
 - 100 
 
 u 
 
 10 “ - - - - 
 
 
 
 - 200 
 
 u 
 
 Smaller stones 8 to 1 carat are worth 
 
 - - 
 
 8 francs. 
 
 12 to 1 “ 
 
 u 
 
 - - 
 
 - 6 
 
 u 
 
 16 to 24 to 1 “ 
 
 u 
 
 - - 
 
 - 4 
 
 u 
 
 In order to show the various 
 
 prices of the Rubies, we 
 
 cite the sale 
 
 at auction of the Marquis de Dree’s collection, 
 
 at Paris. 
 
 
 For a cherry-red Ruby of 
 
 - 2 - 
 
 carats, 
 
 - 1000 francs. 
 
 For a darker Ruhy of - 
 
 - 11-2 
 
 U 
 
 - 400 
 
 U 
 
 For a bluish-red Ruby - 
 
 - 21-2 
 
 u 
 
 - 1400 
 
 u 
 
 For a lighter Ruby - - 
 
 - 3 - 
 
 u 
 
 - 1200 
 
 u 
 
 For a blue Sapphire 
 
 - 6 - 
 
 u 
 
 - 1760 
 
 u 
 
 For an indigo-blue do. 
 
 - 6 3-4 
 
 u 
 
 - 1500 
 
 u 
 
 For a light blue do. 
 
 - 4 - 
 
 u 
 
 - 123 
 
 u 
 
 For a white do. - - 
 
 - 41-2 
 
 a 
 
 - 120 
 
 u 
 
 For an Oriental Amethyst 
 
 11-2 
 
 u 
 
 - 400 
 
 u 
 
 For a fine yellow Topaz 
 
 - 61-2 
 
 u 
 
 - 620 
 
 u 
 
 For a lighter Topaz 
 
 - 61-4 
 
 u 
 
 71 
 
 u 
 
 There are numerous faults or defects to which Sapphires are sub- 
 
TREATISE ON GEMS. 
 
 69 
 
 ject, and which always influence their price, such as clouds, milky or 
 semi-transparent specks, like Chalcedony, white stripes, fissures or 
 knots, &c. The Sapphire, particularly the red and blue varieties, 
 being great favourites in commerce, are often adulterated, not only by 
 other coloured gems resembling them, but also by substituting pastes. 
 Instead of Ruby, we sometimes get the Spinelle, Garnet, Hyacinth, 
 red Quartz, calcined Amethyst, red-burnt Brazilian Topaz, red Tour¬ 
 maline ; and instead of the blue Sapphire, we get the Disthene, Cyan- 
 ite, and the Cordierite,—the hardness is the best test. 
 
 NOTICE OF SOME LARGE SAPPHIRES. 
 
 Tavernier describes two large Rubies said to have belonged to the 
 king of Visapur, one of which weighed fifty and three-quarter carats, 
 and the other seventeen and a half carats. The first was valued at 
 sixty thousand francs, the other at seventy-four thousand five hundred 
 and thirty francs. 
 
 The king of Pegu and the monarchs of Siam monopolize the fine 
 Rubies, as the sovereigns of the peninsula of India have done with the 
 Diamonds. 
 
 The finest Ruby in the world, is in the possession of the first; its 
 purity has passed into a proverb, and its worth, when compared with 
 gold, is inestimable. 
 
 The Subah of the Divan is also in the possession of a prodigiously 
 fine one, a full inch in diameter. 
 
 The empress Catharine of Russia, possessed one Ruby of the size 
 of a pigeon’s egg. 
 
 Blue Sapphires are described by the English Embassy to Ava, to be 
 of the weight of nine hundred and fifty-one carats. Mr. Mawe saw 
 a blue Sapphire of two hundred and ten carats, (two ounces.) In the 
 crown jewels of France, there is one rhomboidal crystal of one 
 hundred and sixty-six carats.* 
 
 VI. COMMON CORUNDUM, DIAMOND SPAR. 
 
 This mineral was formerly brought from China only, when not so 
 well known, and bore the name of Common Corundum, but now 
 belongs to the general family of Corundum. It occurs in crystals 
 
 * The most valuable collection of rougl/and polished gems, and particularly of the 
 Sapphire family, I have seen in the possession of Robert Gilmore, Esq., of Baltimore. 
 Mr. Featherstonehaugh exhibited to me a rough Ruby with a native grain of Platina 
 from North Carolina. In Mr. Clemson’s collection of Cameos is an antique head cut 
 in a large Sapphire of about twelve carats. 
 
70 
 
 TREATISE ON GEMS. 
 
 which are generally coated with some crust, and has a conchoidal 
 fracture; is translucent, and has a lustre between unctuous and mother 
 of pearl, either gray, red, blue green, brown, or whitish in different 
 shadings. It is mostly enclosed in granite, mica slate, dolomite, or mag¬ 
 netic iron, and is found in Piedmont, Cananora, Campo Longo, the 
 East Indies and Sweden. 
 
 All the Corundums, possessing fine and pure colours, are used and 
 cut as jewels, and the impure pieces are pulverized and used for cutting 
 and polishing harder stones, or glass and metals, particularly so in the 
 East Indies and China, and it is called in Madras, the grinding spar. 
 
 III. CHRYSOBERYL. 
 
 The name of this gem is derived from the Greek explaining its 
 colour; it is also called Cymophane. It was formerly classed with 
 the Beryl family, but was separated from that by Werner. 
 
 It occurs, crystalized, in a prismatic form, also in boulders and grains ; 
 is transparent to translucent, and possesses the double refraction in a 
 high degree; its lustre is between unctuous and vitreous ; fracture is 
 conchoidal; asparagus, and olive-green with a tinge of brown, yellow, 
 grey or white colour. Some specimens display, sometimes, a milky or 
 blueish-white shine of lustre. Crysoberyl scratches Topaz'and Rock- 
 crystal very distinctly, but is attacked by Sapphire ; the streak-powder 
 is white, specific gravity, 3.59—3.75. It becomes electric by rubbing, 
 and retains this property for several hours: it is infusible before the 
 blow-pipe, but is slowly fusible into a glass-bead with borax. Its com¬ 
 ponent parts are,—Alumina, silica, and glucia, with some oxide of 
 iron and titanium. In commerce Chrysoberyl is called Oriental Chry¬ 
 solite, and that displaying the shine, is called Opalescent Chrysolite. 
 
 Chrysoberyl is mostly found in loose crystals or in boulders of the sand 
 of rivers in company with other gems, such as Spinelle, Sapphire, 
 Topaz, Beryl, &c. In Brazil, particularly in the diamond district, 
 and more frequently in Termo Minas Novas, Pegu, Ceylon, and 
 Siberia : likewise in Connecticut, (Haddam), and New York, (Sara¬ 
 toga), embedded in coarse granular granite, and accompanied by 
 Garnet and Beryl. 
 
 The Chrysoberyl is cut on a brass wheel with emery, and polished 
 on a pewter wheel with rotten-stone; it is very often cut on cabou- 
 chon, and if perfectly pure and transparent in other forms, is set with 
 gold foil, and is used for rings and pins. 
 
 The Chrysoberyl is in no great estimation on account of its indif¬ 
 ferent fire and colour, but taking a high polish, and occurring trans- 
 
TREATISE ON GEMS. 
 
 71 
 
 parent and pure in colour, those of varying lustre, are of some value, 
 and particularly it is worn in Brazil. At Paris, a Crysoberyl of fine 
 green colour, oval cut, of seven lines length, and five and three- 
 quarters breadth, was sold for six hundred francs, and a very fine 
 Opalescent Chrysoberyl nearly five lines long and four broad, cost six 
 hundred and three francs. 
 
 .For Chrysoberyl has been substituted Apatite, Fluorspar, and Pastes, 
 but it is harder than all; but Chrysolite bears a great resemblance to 
 Chrysoberyl in its external appearance, but is much lighter and softer 
 than the latter. A green Chrysoberyl was found in Terno, of Minas 
 Novas, which weighed sixteen pounds, the largest known, and is in 
 the possession of the crown at Rio de Janeiro. 
 
 XV. SPINELLE. 
 
 This gem was called by the ancients, Carbuncle. It only occurs 
 crystalized, and mostly in the form of an octahedron, and its modifi¬ 
 cations. The crystals are smooth, solitary, and grown together as 
 hemitrapes, loose, often rounded like grains; fracture is conchoidal ; 
 transparent and translucent; possesses simple refraction of light, of a 
 high vitreous lustre, is red, turning in the greatest variety of shadings 
 of blue, brown and yellow. Sometimes v r e find, likewise, blue, black, 
 and green Spinelle, which, however, have no commercial value on 
 account of their impure colour and want of transparency. 
 
 Spinelle scratches Quartz and is attacked by Sapphire ; becomes 
 electric by rubbing; its specific gravity, 3,48—3,64; is infusible before 
 the blow-pipe. According to Berzelius, the Spinelle of Ceylon, when 
 heated, grows first brown, then black, and then opake, which on cool¬ 
 ing, passes into the green and limpid, and ultimately into its original 
 red. Acids do not effect it; its component parts are :—Magnesia and 
 Alumina. The Spinelle is classed by the jewellers and lapidaries 
 according to its various colours. 
 
 1, Ruby Spinelle, or Spinelle Ruby, of a light or dark red, and no 
 milky lustre; shows, if held near the eye, a tinge of rose-red colour. 
 
 2, Ruby Balas, or Balas Ruby, pale-red or rose-red, sometimes a 
 tinge in the brownish or violet. 
 
 3, Almandine Ruby; of a cochineal-red colour, touching on blue, 
 violet-blue, and reddish-brown ; is distinguished from the Garnet, like¬ 
 wise called the Almandine, by its lighter colour, stronger lustre, and 
 greater hardness. 
 
 5, Goutte de Sang, is a fine cochineal or blood-red Spinelle. 
 
 Spinelle is found in clay, and in sand of rivers, with Sapphire, Gar- 
 
72 
 
 TREATISE ON GEMS. 
 
 net, Tourmaline, and other gems. In Ceylon, Pegu, and Cananore, it 
 is cut on an iron or brass wheel, with emery or pulverized diamond, 
 and is polished either on the same or on a copper wheel, with oil of 
 vitriol. 
 
 Spinelle is cut in the same form as the Diamond, and is set with a 
 foil of copper or gold. Its colour is often made more intense, and its 
 faults, such as flaws and specks removed, by calcining them carefully. 
 
 Lustre, colour, and hardness, have made the Spinelle a very favour¬ 
 ite gem, which is used in a great variety of ways, as in rings, pins, 
 necklaces, &c. 
 
 As to the price of Spinelles, it is likewise difficult to determine with 
 accuracy, as so much depends on their properties. If, in perfection, it 
 exceeds four carats, it is usually worth half the price of an equally 
 large Diamond. The Spinelle Ruby and Balais Ruby are the most 
 esteemed Spinelles, and are worth from two hundred to four hundred 
 francs of twenty-four to thirty carats, and such gems are often sold 
 for the true Rubys, (Sapphire.) 
 
 Zircon is of greater specific gravity and less hard than the Spinelle, 
 and shows strong and double refraction of light. Calcined Topaz is 
 distinguished by its electric properties. Burnt Amethysts are lighter, 
 and are scratched by Spinelle. Pastes are likewise substituted for the 
 Spinelle, such as glass coloured with gold-purple, but as the Spinelles 
 are always harder and heavier, the adulterations may soon be detected. 
 
 V. TOPAZ. 
 
 It is not determined whether the ancients meant the same gem 
 as we describe, since the Greeks understood the Topaz to be a trans¬ 
 parent gold-yellow, and the Romans, a transparent green-yellow. 
 The name which, according to Pliny, is derived from Topazos, an 
 island in the Red Sea, has no reference to its colour. Topaz was, 
 in former times, thought to possess great medicinal virtues, such as a 
 remedy for mania, and’a strengthening medicine. The Topaz occurs 
 crystalized as a rhombic prism, but mostly in very complicated forms, 
 such as the Brazilian, Siberian, and Saxonian, and is also formed in 
 boulders. Its fracture is concboidal; transparent and translucent; 
 possesses some double refracting powers, but very vivid vitreous lustre ; 
 clear, straw, sulphur, wine and gold-yellow colours, sometimes with a 
 tinge of violet-blue, greenish and white. Topaz scratches distinctly 
 the Quartz, but is attacked by Sapphire. Its streak-powder is white ; 
 specific gravity is—3,49 to 3,56 : is phosphorescent when heated, with 
 a blueish or yellowish lustre, in small fragments. It becomes electric 
 
TREATISE ON GEMS. 
 
 73 
 
 either by rubbing, heating, or by pressure, and retains the property for 
 more than twenty-four hours. Before the blow-pipe at a strong heat, 
 it is covered with many small bubbles, and partly looses its colour. 
 It is dissolved, fuses slowly with borax, into a white bead: acids have 
 no effect upon it. Its component parts are,—Alumina, Silica, and 
 Fluoric Acid. 
 
 In commerce, Topaz is distinguished by the following names 
 
 1. Water Drops, pebbles (gouttes d’eau) clear, limpid. 
 
 2. Siberian Topaz, white, with a blueish tinge. 
 
 3. Brazillian Topaz, gold-yellow, with a touch of the reddish. 
 
 4. Saxon Topaz, pale wine-yellow. 
 
 5. India Topaz, saffron-yellow. 
 
 6. Brazilian Ruby, light rose-red. 
 
 7. Brazilian Sapphire, light blue. 
 
 8. Aquamarin, sea and mountain green. 
 
 Topaz belongs to the primitive rocks, and is found in chlorite slate, 
 gneiss on gangues, argillaceous shiste, &c.: in Siberia, (Mursinsk 
 and Miask), Brazil, Scotland, Saxony, Bohemia, and in the United 
 States, (Huntington, Connecticut.) 
 
 In Brazil it is found in a decomposing chlorite slate, and is there 
 called Malacheta, on the Brown Hematite cavities or Quarts gaugues, 
 and are, of one inch to one and a half leet thick, and are overlaid by 
 indurated Talc, and of white and brown Kaolin, which is sometimes 
 intermixed with quartz crystals and micaeous iron, which are the 
 surest indications of Topaz. Such Topaz localities are at Yilla Rica 
 and Capao and Lana. Little attention is paid during the dry season 
 to the digging of Topaz ; but with the beginning of the rainy season, 
 the searches for Topaz are undertaken, and the operation for washing 
 and procuring them is performed like that of the Diamond, mentioned 
 under its proper head. 
 
 On places where the Topaz is found in company with tin ore, it is 
 picked out, but where it forms a part of the rock, it is wrought by the 
 mining operations, as in Saxony. 
 
 Topaz is cut on a leaden wheel, either with emery or pulverized 
 Topaz, and is polished on a copper wheel with rotten-stone. Care has 
 to be taken in slitting the foliage. The forms which it is to receive, 
 depend upon its qualities and purposes. The white Topaz is cut in 
 brilliant form with a small table; the blueish Topaz, however, is cut 
 with a mixed form, but it is to be observed that the table-side requires 
 to be higher than usual, the table smaller, and the collect side, with its 
 steps, must be attentively wrought in proportional distance. The yel- 
 
 j 
 
74 
 
 TREATISE ON GEMS. 
 
 low Topaz is mostly cut as brilliant or table-stone, and in setting its 
 back, is supplied with a gold foil, and the pale, with ared coloured foil. 
 Many species of Topaz are set a jour. Topaz assumes, by calcining, 
 a different colour, as also by colouring fluids, as already stated in the 
 introduction. 
 
 The Topaz is in general use of the jewellers for setting rings, pins, 
 ear-rings, seals, or necklaces. Its fragments are pulverized and used 
 for grinding the softer precious stones; this is affected by calcining 
 them first, throwing them in water and pulverizing them aftewards. 
 Topaz is generally of less value now than formerly, owing to the 
 yearly supplies obtained from Brazil, which is about forty pounds. 
 The mine at Ca.pao has yielded about twelve thousand dollars worth, 
 and the supply has been accumulating at Rio de Janerio and Bahia, 
 to such a degree, that it is disposed of at a less price there than at the 
 mines. 
 
 Those most esteemed are the rose-red and the white, or water dropSj 
 Pingos d'cigoa. A Topaz of the size of a bean, is sold at Chapada 
 in the Termo of Minos Novas, at one dollar; one of one carat, is, at 
 an average rate, for eight dollars, a yellow one for three dollars, and a 
 yellow burnt one, for five dollars. In Brazil, very large, fine, and lustry 
 ones bring thirty dollars. 
 
 The Saxonian Topazes are less valued,—yet, good yellow or crim¬ 
 son coloured ones, of nine lines long and seven broad, bring four 
 hundred and twenty francs. 
 
 Aquamarin and Chriysolite are sometimes substituted for Topaz; 
 but they may easily be distinguished from them, not alone by its 
 hardness, fracture and specific gravity, but most particularly by its 
 property to become electric by rubbing. This will prevent the substi¬ 
 tution of either of the above, or those most resembling them ; such 
 as the yellow quartz, chalcedony, or other yellow coloured stones. 
 
 According to the account of Tavernier, the Grand Mogul possesses 
 an octangular polished Topaz of one hundred and fifty-seven and 
 three-quarters carats weight, which has been purchased for sixty 
 thousand dollars. 
 
 Mr. de Eshwege notices a Topaz crystal of ten inches length and 
 four inches diameter. The United States (Connecticut) yield Topazes 
 of an opaque colour, pale, dark orange, and yellow, of twelve inches 
 in length. One of the finest Brazilian Topazes I have seen is in 
 the rare collection of Robert Gilmore, Esq., of three inches length, 
 and perfectly terminated. 
 
TREATISE ON GEMS. 
 
 75 
 
 VI. EMERALD. 
 
 The proper Emerald and the Beryl belong to this mineral species, 
 and thus are distinguished by their colour and crystalline form. The 
 Emerald occurs in six-sided prisms with its modifications ; it scratches 
 Quartz, and is scratched by Topaz. The streak powder is white; 
 its specific gravity is 2,73 to 2,67; it becomes electric by rubbing; 
 it is rounding before the blow-pipe, and forms an opaque black, but 
 becomes a green or limpid glass, with the hardness of Borax. Its 
 constituents are glucia, alumine and silica. 
 
 A, THE PROPER EMERALD. 
 
 The Emerald appears to have been known in the most remote 
 ages, and was the third stone, according to Calmet’s arrangement, on 
 the High Priests breast-plate of judgment, with the name of Zebulon 
 inscribed on it. In the time of Pliny this stone was held in such 
 high estimation, that it was seldom or never engraved upon. The 
 moderns, however, did engrave on the same, as we find in the royal 
 collection at Paris, a head of Henry IV., and one of Louis XIV. 
 It has been excavated from the ruins of Rome and from Hercula¬ 
 neum and Pompeii. But the ancients often included, under this 
 name, other gems of the same colour; such as the Green Fluor, 
 Aquamarin, Jasper, Malachite, &c. They appear to have obtained 
 the Emerald from Egypt. Cailloud has in modern times succeeded 
 in finding the old Emerald mines in the Theban desserts, on the 
 Arabian Gulf, which have been noticed by the ancient authors and 
 by the traditions of the Arabs as coming from the mountains of the 
 Zaharah, when sent on an exploring expedition by the Pasha of 
 Egypt. He describes as having found subterranean mines capable 
 of allowing four hundred men to work; and he likewise found tools, 
 ropes, lamps, and other utensils. He judged from the ruins of the 
 architecture of the temples of a city which he discovered, to be of 
 Egyptian or Grecian form, and about one thousand years old. 
 
 Among the Church treasures of the ninth and tenth centuries we 
 find the Emerald, and the same came into particular notice after the 
 conquest of Peru, where an Emerald of the size of an austrich egg 
 is said to have been idolated by the savage inhabitants. The 
 Emerald was formerly used as medicine and was worn as a prevent¬ 
 ative against epilepsy. 
 
 The Emerald occurs in somewhat depressed six-sided prisims; the 
 latral faces of which are smooth; the fracture is conchoidal to 
 uneven ; is transparent to translucent; displays the double refraction 
 
76 
 
 TREATISE ON GEMS. 
 
 in a slight degree; has a vitreous lustre; is green and Emerald- 
 green with its different shades. 
 
 It is scratched by an English file, and scratches strongly, white 
 glass, and slightly quartz. Its specific gravity is 2,73 to 2,77. Its 
 colour:is owing to the oxide of chrome. An Emerald when calcined 
 and thrown into water, crumbles into pieces of different colours. 
 The purest Emeralds are called the Peruvian. 
 
 The Emerald is found in micaceous Sliiste at Salzburg, in the 
 Zaharah mountains, on Gangues in Peru, in the Argillaceous and in 
 Hornblendeslate. Formerly, the finest Emeralds came from Warta, 
 in Peru, but the mine is either exhausted, or the Indians have filled 
 up the mines before they left them, at the conquest. The best are 
 now found in the valley of Tunca, in Santa Fee, where they occur 
 in granite. The emerald has lately been discovered in Siberia, in 
 the micaceous shiste and is equal to the Peruvian in every respect. 
 
 The Emerald is sawed in pieces with emery, cut on the copper 
 wheel, and polished on a finer wheel with rotten-stone, pumice-stone, 
 tin ashes and water. The step cut and the mixed-step cut, or the 
 table-cut, are mostly used, yet it is sometimes cut as a Brilliant or 
 rose-cut. They are set with a green foil or green satin on their back; 
 or sometimes in a back coloured with mastic, and very black; but 
 if perfectly pure and of fine colour, they are set a jour. On ex¬ 
 posure to air the Emeralds grow by degrees paler. 
 
 The Emerald is, on account of its agreeable green colour, a very 
 favourite ornament; and is used for the most expensive kind of 
 jewellery, but its value depends altogether upon its pure and fine colour, 
 vivid lustre, and size of the specimen. The price of Emeralds was 
 much higher before the discovery of Mexico, but the mines of Peru 
 reduced their price considerably; but now they are getting again 
 dearer, and command always a good price. A small box of fair 
 Emeralds, from Peru, which I saw a few years ago, at the office of 
 the American and Foreign Agency, in this city, which weighed from 
 three to four pounds, was sold afterwards at Paris for nine thousand 
 francs. A good Emerald of fine colour is worth twelve dollars per 
 carat; and the price increases according to its interior qualities. 
 The prices of the best Emeralds of 
 
 4 grains 
 8 “ 
 
 16 “ 
 
 24 “ 
 
 48 « 
 
 is 
 
 u 
 
 18 dollars 
 30 “ 
 
 200 « 
 
 300 « 
 
 1000 « 
 
TREATISE ON GEMS. 
 
 77 
 
 An Emeralds of 24 grains and good colour was sold at the auction 
 of the Marquis of Dree for two thousand four hundred francs. 
 Emeralds of indifferent pale colour are sold for two dollars per carat. 
 The faults which the Emeralds are subject to are, inequality of colour 
 and transparency, dark or white spots, fissures and feathers. 
 
 For Emerald, there is sometimes substituted the green Turmalin 
 and Apatite; the first is easily detected by its property to become 
 electric by heating; but in general, all these stones do not possess 
 the lustre and the hardness of the Emerald. The pastes, in imitation 
 of the Emerald, are so well manufactured, that it is often difficult to 
 discriminate the genuine from the false. The following yields the 
 best imitation of Emerald :— 
 
 1000 parts of discoloured Stratss, 
 
 8 pure oxide of copper, 
 
 02 oxide of chrome. 
 
 An Emerald is said to have existed at the Chapel of Our Lady at 
 Lorretto, in Italy, larger than a man’s head, and for which an 
 Englishman offered ninty thousand crowns. 
 
 The sultan of Onde, in the East Indies, is said to have given to the 
 king of England, among other presents, an Emerald of the size of 
 a hen’s egg. 
 
 The treasury of Vienna is said to contain an Emerald of two 
 thousand two hundred and five carats, which is said to be valued at 
 three hundred thousand crowns. 
 
 The most magnificent specimen of Emerald was presented to the 
 cathedral of Loretto by one of the Spanish kings. It consists of a 
 mass of white Q.uartz, thickly implanted with Emeralds more than 
 an inch in diameter. An Emerald belonging to the crown of Russia 
 is noticed in the Meuiorres de regne de Catherine, Imperatru de Russie, 
 to be of the size of a hen’s egg. A fine crystal in the matrix, is in 
 the museum at Dresden. 
 
 C, BERYL, AQUAMARINE. 
 
 This gem was likewise known to the ancients, who considered and 
 described it as a sea-green precious stone, and called the yellow varieties 
 of this mineral, the Chrysoberyl. It was used by the Romans as 
 ornaments for cups, also for Cameos. The crystals of the Beryl are 
 six-sided, terminated by six-sided pyramids, they also taper gradually 
 from one end to the other; the lateral faces are straited; the fracture 
 is conchoidal or uneven ; transparent or translucent at the angles, with 
 indistinct double refraction, vitreous lustre: the colours are, green blue- 
 
78 
 
 TREATISE ON GEMS. 
 
 ish green, yellowish green or greenish white, bluish, sky, smalts or 
 indigo-blue, straw, wax, or honey yellow; all pale colours; specific 
 gravity—2,67—2,71. According to its colour and transparency, it is 
 designated the common and precious Beryl; under the first are gene¬ 
 rally comprised the greenish and blue varieties, which are also called 
 the Aquamarine, whereas the yellowish varieties are exclusively called 
 the Beryl, and they are generally divided thus:— 
 
 1. Aquamarine, pure pale sky blue. 
 
 2. Siberian Aquamarine, pale greenish yellow, of a vivid lustre, 
 faint colour. 
 
 3. Aquamarine Chrysolite, greenish yellow, and yellowish green, 
 vivid lustre. 
 
 The Beryl belongs to the primitive formation, is found in quartz 
 veins and granite, (graphic granite), is associated with Garnets, Quartz, 
 Chrysoberyl, Shorl, Topaz, &c. The most magnificent Beryls come 
 from Siberia and Rio de Janerio in Brazil, and Aberdeenshire in 
 Scotland, and Limoges, France. The common and translucent Beryl 
 occurs all over the globe, and in the United States in great abundance, 
 where it is without mercantile value. The granite rocks of New- 
 hampshire, (Acworth) have brought forth gigantic Beryls, perfect six- 
 sided crystals, three feet in length and four feet in circumference, and 
 weighing upwards of three hundred pounds, and some with a distinct 
 termination of the crystals. Specimens of this description may be 
 seen in the collection of the Lyceum of Natural History, New York, 
 in Mr. Gilmore’s collection at Baltimore, and in the authors collection. 
 Large quantities of Beryl crystal have also been found in Chester 
 county, Pennsylvania. 
 
 The Beryl is cut on a leaden plate with emery, and polished with 
 rotten-stone on a tin plate, and generally of the brilliant cut, on 
 account of its not possessing much lustre in the interior. 
 
 The foil that is required in mounting, depends upon the colour of 
 the stone; the greenish variety, for instance, is set with a greenish 
 blue foil, the pale is set in a black ground, like the Diamond, or on a 
 silvery foil. 
 
 Beryl is employed in jewellry for rings, pins, ear-drops, seals, &c.: 
 but on account of its softness, it is rendered less lasting, and, as by 
 wearing, it loses all its beauty, it does not command a high price in 
 market, being much below that of the Emerald. 
 
 A Beryl of a carat, averages about one dollar and fifty cents, and 
 the price increases in the same ratio with the number of carats. The 
 Beryl is subject to such faults as spots, feathers, and fissures. 
 
TREATISE ON GEMS. 
 
 79 
 
 For the Beryl, is sometimes substituted Chrysolite, which is softer, 
 however; it is also imitated by paste, which is likewise softer than 
 Beryl. 
 
 One of the largest transparent Beryls, weighing five hundred and 
 ninety five carats, was once in the possession of a mineralist at Vienna. 
 In 1811 a Beryl of fifteen pounds and one of four pounds pure, were 
 discovered in Brazil. In 1825, a beautiful rounded Brazilian Beryl 
 of four pounds weight was offered for sale for six hundred Lst. 
 
 Mawe describes a pure transparent Beryl altogether free of faults, 
 seven inches long and three-quarters of an inch thick. 
 
 VII. ZIRCON. 
 
 Zircon and Hyacinth were formerly separated, until the improve¬ 
 ment in chemical analysis, which proved the same constituents to exist 
 in both, particularly the Zirconia, a peculiar earth : they have, there 
 fore, ever since been considered as two varieties of one and the same 
 mineral. Zircon is also called Jargon, and this name is either of 
 Ceylonese or French origin. The ancients considered the Hyacinth as 
 that gem which is now known by the name of Carbuncle, and meant 
 by their true Hyacinth a dark Amethyst. The Zircon was formerly 
 used as a celebrated medicine. 
 
 The Zircon crystallises in four-sided prisims, terminated by four¬ 
 sided pyramids, and with various modifications; the crystals are 
 either smooth, rough, or uneven ; it occurs likewise in rounded 
 pebble ; is transparent and translucent; double refraction in a great 
 degree ; pf a vivid vitrous lustre, approaching sometimes to adaman¬ 
 tine. Hyacinth red to yellow and brown colour; also red, gray, 
 white, brown, and greenish-gray. It scratches, tolerably, quartz, but 
 is attacked by the Topaz; its streak yields a white powder; specific 
 gravity is 4,41 to 4,60; becomes electric by friction; is infusible 
 before the blowpipe, but looses its colour at a low heat: the yellowish- 
 brown. however, becomes redder; acids do no act upon it. Its chem¬ 
 ical constituents are Zirconia and Silica, with about two per cent 
 oxide of iron, which is the colouring principle. 
 
 lst. The Zircon, called by the jewellers Celylonian Zircon, fire-red 
 yellow, yellowish-green, and gray. 
 
 2d. The Hyacinth is called by the jewellers the Oriental Hyacinth, 
 which is of a Hyacinth-red, deep-red with a touch of the brown, and 
 sometimes orange-yellow colour. The Zircon occurs in primitive 
 rocks, and forms a part of the Zircon Syenite of Norway and other 
 countries. It is also found in the Gneiss, Granite, Amygdaloid, and 
 
80 
 
 TREATISE ON GEMS. 
 
 Basalt. It is likewise found in the beds of rivers ; and the localities 
 are Ceylon, Pegu, Madras, France, Bohemia, Saxony, Italy, Siberia, 
 Scotland, Canadas, North Carolina, &c. 
 
 The Zircon is cut with Diamond powder, or emery on a copper 
 wheel; and is polished with rotten-stone on a tin plate, and generally 
 in the rose, table, or thick-stone cut, and sometimes the Brilliant form. 
 The foil generally used in mounting, is that corresponding to its 
 colour; or it is mounted in a black ground. If the Zircon is calcined 
 in a crucible filled with lime, it looses its colour almost entirely, and 
 has then the appearance of a pale straw-yellow Diamond, for which 
 it may also be substituted. It is employed in jewellery for rings, 
 breastpins, and ear-rings, or for ornamenting watch cases and snuff 
 boxes; also for jewelling watches and for supporting fine balances. 
 The value of the Zircon depends principally upon the purity of the 
 colour, and that of the Hyacinth is preferable to that of the Zircon : 
 and a carat of the first is worth from fifteen to twenty dollars. The 
 Zircon is imitated by pastes, which may easily be detected by their 
 lustre, hardness and specific gravity ; likewise the burnt Topaz may 
 be substituted for it. 
 
 VIII. GARNET. 
 
 The garnet was well known to the ancients, who considered the 
 Carbuncle as the same mineral, representing the whole species. It 
 was found among the ruins of old Rome in a variety of cut forms. 
 But the name Garnet is of modern origin, and probably on account 
 of its being found mostly in grains. 
 
 The Garnet crystallises in dodecaedal forms with many modifica¬ 
 tions. The crystals are sometimes flattened into tables , also in round 
 angular grains, and massive; the structure is imperfectly lamellar; 
 fracture more or less conchoidal, sometimes uneven and brittle ; lustre 
 shining vitreous; transparent and translucent; the colour is blood, 
 cherry, or brownish-red, but almost invariably mixed with a violet, 
 or blue tinge ; sometimes, however, we find the Garnet of a yellow, 
 green, brown, or black colour. 
 
 The red Garnet scratches quartz faintly, but is attacked by Topaz, 
 and even by the file ; its powder is reddish-green; specific gravity 
 is from 4 to 4, 03 ; becomes electric by friction ; heated by itself, the 
 Garnet grows darker, but resumes its colour when cooled ; fuses before 
 the blow-pipe to a black pebble. Its chemical constituents are Silica, 
 Alumina, Protoxides of iron and Manganese. 
 
 The Garnet has its names according to the different shadings of 
 the colour. 
 
TREATISE ON GEMS. 
 
 81 
 
 1st. Syrian Garnet, which is also called the Oriental and orecious 
 Garnet, Almandin, Carbuncle, which is of a blood-red, dark crimson 
 colour. 
 
 2nd. Bohemian, or Ceylonese Garnet is called the Pyrope ; wine- 
 red, nearly orange-yellow, deep coloured. 
 
 3d. Vermeille or Aplome, with a deep shade of orange-yellow. 
 
 The red Garnet occurs in granite, gneiss, mica talcose and chlorite 
 shistes, and serpentine; also in loose crystals, small boulders, grains, 
 and in alluvial. It is found in Saxony, Bohemia, Tyrol, Syria, 
 Corinthia, Spain, Norway, Greenland, Ceylon, Hindostan, and in the 
 United States, viz:—New York, Connecticut, Massachusetts, New 
 Hampshire, and other places. 
 
 The Garnet is mostly obtained from the digging and collecting the 
 alluvial, which grains are more useful to the lapidary than those 
 occurring in the rocks. In Bohemia, where there is a considerable 
 trade in Garnets, they are seperated from the earth by levigation, 
 and then assorted in different sizes, afterwards washed over again, 
 assorted as to colour and quality, and according to the quantity 
 required for balancing a certain weight, such as half an ounce; 
 they are called 32, 40, 76, 100 to 40 ; very seldom they find them 
 16—20 weighing together half an ounce. 
 
 The larger Garnets are cut on the leaden wheel with emery, or 
 their own powder, and polished with rotten-stone or oil of vitriol, on 
 a tin plate in the form of Brilliants, Roses, Tablestones, or en 
 cabochon, or with two rows of facets at the girdle; and very often 
 Garnets are brighter, and more agreeable by excavating them circular 
 on the bottom, when they are then called Garnet Cups. I have in 
 my possession several large excavated Garnets, and I have seen at 
 Berlin, in 1828, such Garnets of two and three inches size. 
 
 Fine Garnets are set a jour, others are set with a gold or violet 
 foil at the base. Smaller Garnets are wrought on a large scale in 
 manufactories for that purpose. They are first perforated by the 
 Diamond, by means of a small point, and then of a larger, and at 
 last a finer point of the Diamond; they may perforate daily one 
 hundred and fifty Garnets. 
 
 The finest Garnets are cut in Brilliant form, and with regular 
 facets, on a plate of fine sand-stone, with sweet oil and emery. One 
 man can finish thirty such Garnets in one day. The polishing on 
 wooden or leaden plates, with rotten-stone or oil of vitriol, is performed 
 by women and children. More than twenty thousand Garnets are 
 yearly brought to market from a single manufactory. 
 
 K 
 
82 
 
 TREATISE ON GEMS. 
 
 Garnets are much worn in jewellery, such as rings, breast-pins, 
 ear-rings, necklaces; and sometimes snuff-boxes are also cut out of 
 the larger ones from Greenland, Syria, or Tyrol; and the inferior 
 pieces, unfit for cutting, are calcined and reduced to powder, and 
 employed as material for polishing other gems. 
 
 The value of the Garnet is determined by the degree of perfection 
 as well as colour, purity, and size. On account of their peculiar 
 deep colour, they are to be cut very thin; and all such Garnets as 
 retain their fine colour, without being cut too thin, are held in high 
 estimation, and stand in value near the Sapphire. A Syrian Garnet 
 eight and a half lines long, and six and a half lines broad, and cut 
 octangular, was sold at the auction of the Marquis de Dree for three 
 thousand five hundred and fifty francs. A fire-red oval Ceylonese 
 Garnet, eleven lines long and seven broad, was sold for one thousand 
 and three francs. They are generally sold by the pound holding 
 from sixty to four hundred, valued at about eight to ten dollars 
 per pound. But a set of one thousand of the best selected Garnets, 
 well cut, is sold at about sixty dollars. The Garnet is harder than 
 the Idocrase, and the oxide of tin; but the latter is heavier. 
 
 The Garnet is very well imitated by pastes, which are, however, 
 softer and lighter, and may likewise be distinguished in many other 
 respects. 
 
 The following composition yields a superior ‘"imitation of the 
 Syrian Garnet:— 
 
 To 1000 parts Strass 
 
 500 “ glass of antimony, 
 
 4 “ cassius purple 
 4 oxide of manganese. 
 
 IX. ESSONITE, CINNAMON STONE. 
 
 This gem was formerly considered identical with the Hyacinth, 
 under which name it passes yet in commerce, and among the manu¬ 
 facturing jewellers; and in Prance it is called Hyacinth de Ceylon ; 
 it also is called in mineralogical works Cannel or Cinnamon Stone, 
 which name it received from the Dutch gem dealers, on account of 
 its resemblance to the oil of cinnamon. Werner was the first who 
 named this stone by the above name. 
 
 Essonite occurs in crystals and grains ; fracture is conchoidal and 
 uneven; it is transparent and translucent; has the simple refraction 
 of light; the lustre is between vitreous and resinous; is deep-red, 
 hyacinthed, and orange-yellow ; it scratches glass and quartz indiffer- 
 
TREATISE UN GEMS. 
 
 83 
 
 cntly, but is attacked by Topaz ; its powder is white ; specific gravity 
 is 3.5 to 3.6 ; it becomes electric by rubbing; acts sometimes on the 
 magnetic needle; fuses easily before the blow-pipe into a clear green¬ 
 ish glass; borax and acids do not affect it. 
 
 Essonite is found in the sand of rivers, and in the primitive rocks 
 of Ceylon ; also in Scotland. 
 
 It is treated like the Garnet, by being cut on a copper plate with 
 emery, and polished on a tin wheel with rotten-stone. It also receives 
 the form of other gems, and when set it is mounted with a foil 
 answering to its colour. 
 
 For rings and breast-pins Essonite is distinguished from the Zircon 
 by its smaller hardness, less specific gravity, diminished lustre, and 
 simple refraction of light. Garnet is heavier, and Idocrase is lighter 
 than Essonite. 
 
 X. TOURMALINE. 
 
 This mineral is as yet very little known among jewellers, and the 
 trade in general, although it has been in commerce for a number of 
 years past, but under other names, such as Red Tourmaline, or the 
 Siberite, brought from Siberia, and sold in the trade as Oriental Ruby. 
 
 The Tourmaline was first introduced as a gem by the Dutch, who 
 imported it from Ceylon. The Tourmaline occurs in crystals and 
 crystalline masses, and its forms are six,—nine and twelve sided 
 prisms, with various truncations and terminations, which commonly 
 differ in the number and size of the faces at the two ends. The 
 crystals are long, striated and complete; or aggregated into irregular 
 masses; the fracture is conchoidal and uneven, semi-transparent to 
 opaque. It has a double refraction of light, which, however, is only 
 visible in small pieces ; has a vitreous lustre; the colours are blue, 
 red, green, and brown in their different shades. Several colours may 
 often be observed in one and the same crystal; as, for instance, in 
 the Rubelite from Paris, in Maine, and Chesterfield, Massachusetts, 
 enclosed by the green Tourmaline; and the colour often changes by 
 its different layer. 
 
 Tourmaline scratches glass slightly, but is scratched by Topaz ; its 
 powder is white ; its specific gravity is 3.0 to 3.3 ; it becomes electric 
 by rubbing, that end having the greatest number of faces being posi¬ 
 tive, the other negative. Before the blow-pipe it intumesces more or 
 less, does not fuse, but vitrifies on the edges and then turns green, 
 and then yellow, then red, then milk-white, then blue, and then 
 black. Borax dissolves it pretty easy, efferversing in a clear bead. 
 The chemical composition of the Tourmalines is at great variance— 
 
84 
 
 TREATISE ON GEMS. 
 
 alumine, silica, oxide of iron, oxide of manganese, and boracic acid ; 
 those from different, localities contain, either potash, soda, lithia, or calcia. 
 The following are the different varieties, not reflecting, however on the 
 white, yellow, and black Topaz or Shorl, they not being used as gems. 
 
 1. Siberian Tourmaline, (Siberite, Rubellite, Apyrite,) which is of 
 a carmine or hyacinth red, purple or rose-red into the violet; sometimes 
 by looking through in one direction, the red colour changes in another 
 to the blue colour. 
 
 2. Indicolite, (Brazilian Sapphire), of indigo, lasulite, or prussian 
 blue colour. 
 
 3. Brazilian Tourmaline, (Brazilian Emerald), of a grass-green 
 or olive-green colour. 
 
 4. CeyIonian Tourmaline, (Ceylon Chrysolite) of a greenish yellow 
 colour. 
 
 5. Electric Shorl, of a yellowish, reddish, liver, or blackish brown 
 colour. 
 
 The Tourmaline occurs in rocks, such as granite in layers and 
 gangues and in boulders; it also occurs in the beds of rivers, and the 
 localities are—Siberia, St. Gothard, Ceylon, Brazil, Sweden, Saxony, 
 Moravia. In the United States, Tourmalines are abundant, but there 
 are very few localities of the better varieties, as Paris, Maine, and 
 Chesterfield and Goshen, in Massachusetts. 
 
 The Tourmaline is cut on a brass or leaden wheel with emery, and 
 polished with rotten-stone on a tin plate; it receives various forms, 
 such as the step and table-cut. If of a pure colour it is set a jour , 
 otherwise it is done with a foil corresponding to its colour; but the 
 Electric Shorl is sometimes set so as to remove from its mounting in 
 order to perform experiments. The value of the Tourmaline depends 
 upon its colour, purity and size. The Siberite and Rubelite stands 
 highest in estimation. A Siberite as large as five lines, is worth about 
 an hundred and fifty dollars; and one of four to twelve lines, good 
 colour and pure, is worth about fifteen hundred dollars. The Rube¬ 
 lite from Paris, Maine, has become very rare, and it is much to be 
 regretted that not more attention is paid to obtaining a fresh supply, 
 as they are of an exceedingly fine purple colour, and perfectly trans¬ 
 parent. I have a few polished Rubelites and green Tourmalines, in 
 my cabinet, which I value equally as high as any gems. 
 
 The dark green Tourmalines of six lines long and four broad, are 
 sold in Paris for eighty francs, and the light green of the same size, 
 for forty francs. The most splendid Siberite is at the British Museum, 
 
TREATISE ON GEMS. 
 
 85 
 
 having been presented by the king of Ava to colonel Syrnes; it is 
 valued at one thousand pounds sterling. 
 
 The Tourmalines may at all times be readily distinguished from 
 other gems or pastes which are sometimes substituted, by its property 
 of assuming polaric electricity after being heated. 
 
 XI. Q.UARTZ. 
 
 This mineral is diffused all over the globe. Its varieties are very 
 numerous and various, and many of them are employed for different 
 purposes in jewellery and ornaments. It occurs massive, in concretions, 
 in confused crystaline masses, and in crystals, of which the form 
 is the six-sided prisnj, terminated by six-sided pyramids; also, the 
 dodecahedron, or double six-sided pyramids. Quartz scratches glass 
 and Felspar, but is attacked by Topaz. Its hardness is 7.0, and its 
 specific gravity, 2.5 to 2.7; is by itself transparent, and possesses a 
 vitreous lustre; becomes electric by rubbing : it is infusible before the 
 blow-pipe. Acids, except the fluoric acid, do not act upon it. Silica 
 is the only essential component part of quartz: but some varieties 
 contain iron, alumine or lime. 
 
 A, ROCK CRYSTAL. 
 
 This mineral was known in early ages. It was highly esteemed 
 by the Greeks on account of its purity and very regular formation. 
 Theophrastes states that it was cut principally as seals, and the ancients 
 made great use of it for ornaments, particularly before the art of 
 making glass had reached to much perfection. Among the many 
 vessels which were cut in the form of cRps, vases, &c., were two fine 
 bowls and chalices in the possession of the tyrant. Nero, who had 
 purchased them at a large sum. The Rock Crystal was also used as 
 a medicine. 
 
 It is found either crystalized, the primitive form of which is the 
 rhomboid, extended to a six-sided prism, and a great variety of forms 
 and modifications, such as truncation or re-placement of their edges, 
 or solid angles, &c. It is also frequently found in groups, also in the 
 cavities of other minerals, or in incrustations, as small, but very per¬ 
 fect crystals, the pyramidal terminations of which have a high polish, 
 and the specimen appearing as if it was studded with gems. Many 
 specimens of this description were brought from Vermont but a 
 few years ago, and were eagerly purchased by the jewellers of this 
 city for rings, ear-rings, and breast-pins. Rock Crystal has a con- 
 choidal fracture; is translucent and transparent; double refraction of 
 
86 
 
 TREATISE ON GEMS. 
 
 light; perfect vitreous lustre ; is limpid, white, brown, black or yellow; 
 scratches glass; specific gravity, 2.65. The electricity acquired by 
 rubbing iasts for thirty minutes. Before the blow-pipe, when coloured, 
 it is made limpid. The following varieties of it are made known by 
 their names and characters :— 
 
 1. The Pseudo Diamond, (Bohemian or occidental Diamond,) which 
 is the limpid, colourless Rock Crystal cut and polished. 
 
 2. The iridescent Quartz is that variety of Rock Crystal, the interior 
 of which is replete with fissures and cracks, so that the refraction of 
 the rays of light produce the rainbow colours. 
 
 3. Citrin, (Bohemian Topaz, Occidental Topaz, j’ellow Quartz, 
 Scotch Pebble), which is of a pale, ochry, gold, white, lemon yellow 
 or brownish yellow colour. The false Cairn gouram of Brazil is a 
 beautiful variety of yellow Quartz. 
 
 4. Smoky Topaz, (Cairngouram or true Scotch Pebble, brown 
 Quartz, Smoky Quartz), is of smoky or brown colour. 
 
 5. Morion, is of charcoal black or brownish black colour. 
 
 6. Hair or Needlestone, or such Rock Crystal as has, in its interior, 
 foreign substances, as Rutil (red oxide of Titanium) manganese, iron, 
 chlorite, amianthos or asbestos, and when the stone is so cut as to 
 represent the hair or needle in upright position, they are then called 
 either Venus hair (cheveux de Venus ) or Love’s arrows (Jieches d ’ 
 amour dj 
 
 Rock Crystal occurs on gangues, rock cavities in the oldest geolo¬ 
 gical formations ; it is also occasionally found in some modern rocks. 
 
 The principal localities are, the highlands of Tyrol and Switzer¬ 
 land, Madagascar, Dauphiny, Cornwall, Hungary, Scotland, Ceylon, 
 and Siberia ; in the United States, on Lake George and Trenton Palls, 
 in the state of New York, very perfect and completely terminated trans¬ 
 parent crystals with their endless modifications, and some of five inch 
 size, and some containing drops of water. It is also found in Wind¬ 
 ham, Vermont, where the drusy variety occurs, which is extremely 
 beautiful and of variegated colours. About two years ago, it had a 
 great many admirers, and was quite generally worn in broaches, rings, 
 &c. It is also found in Maryland, Massachusetts, and on the Cats- 
 kill mountains. 
 
 It is obtained in Switzerland and some other countries by mining 
 after it, which is those cavities geologically or mechanically traced by 
 the veins from the Quartz veins, are sounded by them in granite veins 
 or other rocks by means of instruments, and when hollow, extensive 
 preparations are made for procuring the whole produce of the cavities 
 
TREATISE ON GEMS. 
 
 87 
 
 which sometimes amounts to several tons. It is likewise procured from 
 the sand of rivers, and it passes then under the name of Flints; also 
 in gangues or veins of other minerals. The smaller and clearer trans¬ 
 parent ones are generally employed in jewellery and ornaments; but 
 the larger specimens are first assorted and then split or cleaned, and 
 the smaller pieces are then sawed through with a copper wire, emery 
 and oil, into the desired sizes, when they are ready for being cut on 
 copper or leaden discs, with emery and water, and then polished on 
 tin plates with rotten-stone, putty, bol, or other fine powder ; or they 
 may be polished on wooden wheels lined with fur or leather. The 
 forms which they generally receive from the lapidary, are the brilliant, 
 rose, or table. The Iridescent Quartz, and the Hair or Needlestones, 
 are only cut concave. Those specimens that have a full pure wine 
 yellow colour, is best cut in steps. When mounted, they are either 
 a jour, or with'a black foil. Those which are spotted or of irregular 
 colour, may be discoloured by careful calcination in crucibles, with 
 lime, sand, or pearlash, which likewise increases the lustre. The crys¬ 
 tal may be bored with a diamond point, also engraved, and figures 
 may be etched in it by means of fluoric acid. It is mostly used for 
 pins and rings, also for the base of the doublets, likewise for a very 
 great variety of ornaments, such as seals, gems, snuff-boxes, cane 
 heads, &c.: likewise for imitating the real gems, by being coloured 
 and immediately immersed in a solution of colouring water, whereby 
 the colour is very closely imitated. It is likewise the base of all the 
 pastes or Strass. 
 
 Its value is by no means as high as formerly, when the demand 
 for it was great for setting them in buckles, buttons, &c. Articles made 
 of large pieces of it, or those containing slender needles, hair, moss, or 
 other incrustation, or imitation of other substances, are yet somewhat 
 esteemed. In their natural state, if quite clear, as they are received 
 from Madagascar, Switzerland, and Brazil, they are sold for from one 
 to ten dollars per pound ; but when cut for seal-stones, or breast-pins, 
 they are sold mostly by the jewellers of this country, as white Topaz, 
 and commands a fair price. Well cut seal-stones are sold at from 
 five to twenty dollars. Those of the brilliant cut are sold from fifty 
 cents to a dollar a piece. The largest Rock Crystal is said to be in 
 the collection of Mr. Rafaelli, artist at Rome, and a large Candelabre of 
 Iridescent Quartz, in the Vatican. The proprietors of the American 
 Museum of this city, can boast of having one of the largest speci¬ 
 mens of Rock Crystal from Brazil. It weighs two hundred and 
 twelve pounds, is two feet and a half high, and one foot in diameter, 
 of a perfect six-sided prism. 
 
88 
 
 TREATISE ON GEMS. 
 
 Rock Crystal may be easily distinguished from white paste, called 
 Strass, as the latter is heavier on account of the metallic oxides con¬ 
 tained in the composition. 
 
 C, AMETHYST. 
 
 This gem has been known since the earliest ages of Greece and 
 Rome, the name of which is of Greek origin. Its colour being con¬ 
 sidered that of new wine. The ancients believed that wine drank 
 from an Amethyst cup would not intoxicate. Its name occurs in 
 Scripture, being the ninth stone in order on the High Priest’s breast¬ 
 plate of judgment, with the name Isachar engraved thereon. Amethyst 
 was always used for engraving. The bust of Trojan, in the Royal 
 Library at Paris, and the Apollo Belvidere, the Farnese Hercules, and 
 the groups of Laocoon, are splendid specimens of it. It occurs mass¬ 
 ive in boulders, or in hexahedral prismatic crystals, terminated by hex- 
 adral pyramids. Its crystals are rarely as distinct as those of quartz, 
 being, for the most part, laterally aggregated by the whole prism, the 
 terminal pyramids alone being separate from each other ; conchoidal 
 to splintry ; fracture, transparent and translucent; vitreous lustre, of 
 high and dark violet blue, and from its richest tinge to almost colour¬ 
 less, one and the same specimen. It scratches white glass, gives fire 
 with steel, but yields to the file. Its specific gravity, 2.75 ; becomes 
 electric by rubbing, which lasts, however but half an hour. Before 
 -the blow-pipe it loses its colour. Its component parts are pure quartz, 
 coloured by manganese and iron. It occurs in veins of the older 
 formations, and forming the interior parts of agate balls or Geods in 
 the mygdaloid and trapp rocks of Hungary, Silesia, Saxony, Tyrol, 
 Oberstein, and as boulders of the splendid specimens in Ceylon, 
 Siberia, and Brazil. It is wrought in the same manner as the Rock 
 Crystal, being cut on a copper wheel witli emery, and polished on a 
 tin plate with rotten-stone. In order to raise its lustre, many faces, 
 and very frequently those of a rose diamond, are given to it in cutting. 
 It is sometimes cut in the form of a brilliant, and when set, it is sup¬ 
 plied with a blue or red foil, provided the Amethyst is pale, for the deep 
 coloured ones do not require any artificial assistance. It is used in 
 almost every description of jewellery, such as rings, ear-rings, and 
 breast-pins ; but to its best and showy advantage, it is set in necklaces, 
 and it is the only coloured gem which may be worn with mounting, 
 an advantage which adds to its value. The Amethyst, likewise, is no 
 longer in such estimation as formerly, but the colour, when intense 
 and uniform, as also the size, contribute greatly to its value, and good 
 
TREATISE ON GEMS. 
 
 89 
 
 well cut Amethysts, of one carat, are worth from three to five dollars, 
 and so on in proportion to size : an Amethyst of 15 lines long and 11 
 lines broad, exquisitely fine, was valued at five hundred dollars. 
 
 The best Amethysts now in commerce come from Ceylon, Siberia 
 and Brazil; the first are commonly called Oriental Amethysts, which 
 however must be carefully distinguished from a much more valuable 
 gem, the true oriental Amethyst, which is the violet Sapphire. I have 
 in my collection a quantity of the Brazilian Amethysts which are of 
 an intense violet colour, and very large specimens. 
 
 The Amethyst is often imitated by fluorspar or violet-blue lime- 
 spar ; both however are softer than Amethyst: the lime is lighter, and 
 the first is heavier than Amethyst. But it is imitated very strikingly 
 by pastes, so that with great difficulty the real is to be distinguished 
 from the imitation ; which however is somewhat heavier, on account 
 of the metallic oxides contained in the composition. The following 
 is the best receipt for imitating the Amethyst: add to 
 1000 parts of Strass 
 
 8 ” of oxide of manganese, 
 
 0.2 ” purple of Cassius, and 
 
 500 ” oxide of cobalt. 
 
 One of the largest geodes of Amethyst was brought into England 
 in 1819, weighing one hundred and fifty pounds ; two feet long and 
 fourteen inches broad, containing the most magnificent crystals and of 
 the deepest violet colour. On account of having been set down at too 
 low a price at the custom house, which was sixty-five pounds sterling, 
 it was confiscated. 
 
 C, COMMON QUARTZ. 
 
 But a few varieties of the common Quartz are used in jewellery, 
 which are: 
 
 1, the Rose Quartz, 
 
 2, the Cat’s Eye, 
 
 3, the Prase, and 
 
 4, the Avanturin. 
 
 1. ROSE QUARTZ. 
 
 This mineral generally occurs massive; is but semi-transparent, 
 and translucent on the edges ; has a vitreous lustre; conchoidal and 
 splintry fracture; is of rose-red colour ; sometimes giving a shine of 
 mother-of-pearl. It scratches glass, has a specific gravity of 2.64 to 
 
 L 
 
90 
 
 TREATISE ON GEMS. 
 
 2.67, grows paler before the blow-pipe ; it owes its colour to the oxide 
 of manganese. 
 
 Rose Quartz occurs in gangues of granite and gneiss, particularly 
 fine in Sweden, Bavaria, Bohemia and Siberia, as also of a beautiful 
 dark colour in New-Hampshire and Massachusetts. 
 
 Rose Quartz is cut and polished for jewellery, such as rings, breast¬ 
 pins and snuff-boxes ; it is cut on a copper wheel with emery, and 
 polished with rotten-stone and putty on a tin plate, receiving the form 
 of a cabochon or table, and when set requires a foil coloured by car¬ 
 mine or solution of gold, as it fades when exposed a long time to the 
 light. The Rose Quartz is not held in great estimation ; but the 
 colour as well as the lustre may be resuscitated in the faded Rose 
 Quartz by being left for some time in a moist place. 
 
 A vase of Rose Quartz was in the possession of the Marquis de 
 Dree, of nine inches high and two inches diameter. 
 
 2. cat’s eye. 
 
 The name of this mineral is derived from the peculiar play of light 
 perceptible on its surface, by which it resembles the rays of the eyes 
 of a cat; it is not ascertained whether the ancients knew the same, and 
 whether it was comprised in their Asterias ; but it is well known that 
 Cat’s Eye is in high estimation among the Malabars and Moors; and 
 it is worn through the whole East, where it is employed as an amulet, 
 being believed to possess the virtue of enriching the wearer. 
 
 Cat’s Eye occurs massive, and in more or less roundish pieces ; has 
 a conchoidal fracture, is translucent and transparent sometimes on one 
 end ; shining lustre, between vitreous and resinous ; gray and brown, 
 green, red and yellow colour; it presents a peculiar floating light, which 
 is particularly visible when cut in high cabochon, as it usually is when 
 brought to market; it scratches glass ; has a specific gravity of 2.56 
 to 2.73, and contains besides the silex, some alumina, calcia and oxide 
 of iron, as 95 silex, 1.75 alumina, 1.50 lime, and 0.26 oxide of iron. 
 In many specimens there may be observed small parallel white fibres, 
 which are supposed to be the cause of its peculiar play of light; but 
 the semi-transparent varieties, which are equally chatoyant as the more 
 opaque ones, offer no such appearance. This leads to the conclusion 
 that the amianthus in its finest fibres displays the phenomenon, and 
 the chemical analysis of the latter corresponds with the additional 
 constituents of the Cat’s Eye. By exposure to a strong heat it loses 
 its lustre and transparency ; and in small fragments is fusible before 
 the blow-pipe. Cat’s Eye is found, in the fragments of gangues and 
 
TREATISE ON GEMS. 
 
 91 
 
 boulders, of very small size, never larger than a hazel-nut; Ceylon, 
 the coast of Malabar, Hartz mountains, Bavaria, and in this country, 
 in Vermont, New-York, &c. Ceylon, where the finest Cat’s Eyes 
 are found, sends them abroad already cut and polished en cabochon ; 
 but very often they are cut over again on a copper wheel with emery, 
 and polished on a tin plate; it receives in setting a gold-foil. The 
 value depends principally upon its intrinsic properties, size, colour and 
 degree of play of light. Of the nearly opaque varieties, the red and 
 the almost white are the most esteemed, and such are sold usually 
 from ten to twenty dollars ; and a stone of the size of a square inch, 
 and otherwise perfect in its properties, is worth from eighty to one 
 hundred, dollars. 
 
 In the imperial cabinet of Vienna, a five inch long Cat’s Eye, of 
 yellowish brown colour may be seen. 
 
 3. PRASE. 
 
 This mineral is mentioned by Pliny; but it is not certain whether 
 he meant the same substance, and more probably he alluded to the 
 Emerald ; for the same mineral is at the present time called the 
 Emerald Mother or Matrix by the jewellers. Prase occurs massive 
 and crystalized; has a conchoidal fracture; is translucent on the 
 edges; between vitreous and resinous lustre ; garlic-green colour, the 
 origin of which is actinolite intermixed in the silex. It scratches glass, 
 has a specific gravity of 2.66 to 2.88, and is composed of silex and 
 alumina, oxides of iron and manganese. It is found in Saxony, 
 Tyrol, Styria, Hartz and the island of Elba. It is used for rings and 
 pins, also for snuff-boxes and other jewellery, and is cut en cabochon, 
 and set with a gold foil at the base, by which its colour is heightened 
 and rendered more agreeable. It is used in mosaic works, as in the 
 foliage, and likewise in the mounting of Rubies, in order to raise their 
 colour. Prase does not stand in great estimation; for although it 
 assumes a very good polish, yet loses the same on long exposure to 
 the air, and grows spotty. 
 
 4. AVANTURINE. 
 
 This mineral, bearing a resemblance to a glass paste, formerly 
 manufactured in Italy, has always had the above name. It is a 
 brown or red quartz, which is massive and translucent, to opaque; 
 has a resinous lustre, and its fracture is splintry and uneven: it is 
 penetrated with gold or brass yellow glistening fissures, caused by the 
 refraction of light, or by innumerable mica leaves. It scratches white 
 
92 
 
 TREATISE ON GEMS. 
 
 glass, has a specific gravity of 2.64 to 2.68 : silex, with some alumina 
 and water are its constituents. 
 
 The Avanturine is found in the Uralian mountains, Styria, near 
 Madrid, Nantes, Scotland, &c. It is used for ring stones, ear-rings, 
 and snuff-boxes. It is cut on a copper wheel with emery, and polished 
 with rotten-stone on a tin plate; it is cut semi-lenticular or oval, does 
 not take easily a good polish, but may be improved by rubbing the 
 stone with oil of almonds. The value of the Avanturine is much 
 depreciated of late, and its imitation of glass paste, which is generally 
 called the Goldstone, is by far superior to the real stone, which has 
 nothing but hardness in its favour. This paste is manufactured in 
 great quantities in France, by throwing the finest impalpable powder¬ 
 ed brass into a quantity of colourless strass, or into a composition of 
 105 parts quartz, 
 
 85 ” purified potash, 
 
 230 ” tin and lead alloy, 
 
 50 ” brass powder. 
 
 D, JASPER. 
 
 This mineral is of oriental origin, and is very often mentioned in 
 the Bible. It was the sixth stone in the plate of the high priest. 
 Jasper was well known to the Greeks and Romans; and according to 
 Pliny, who has described several varieties, the best came from Scythia, 
 Cypria and Egypt. The lapidaries formerly made much use of it in 
 their works ; and particularly the Egyptian Jasper afforded them 
 great material; as for instance the column of Memnon ; the founda¬ 
 tion of the column of Pompey : and we find daily among the exca¬ 
 vations of Herculaneum and Pompeii fragments of ruins composed 
 of Egyptian Jasper. 
 
 Jasper occurs in enormous masses : has a conchoidal fracture and 
 is opaque ; its lustre slightly resinous like wax, often dull; of white, 
 red, yellow, green, blue, brown and black colours. It scratches glass, 
 but yields to rock crystal. Its specific gravity is 2.31 to 2.67. 
 
 It is found in gangues, more seldom in strata, in Egypt, Bohemia, 
 Saxony, Tyrol, Hungary, France, Italy, Spain, Siberia, and in the 
 United States, principally in Florida, North Carolina, Massachusetts, 
 &c.; also in Nova Scotia. 
 
 According to their varieties, which are very numerous, that is in 
 colour and structure, they receive their names ; but they may yet be 
 classified into the following two divisions : 
 
 a, Egyptian Jasper, (Egyptian Pebble), which occurs in spheroidal 
 
TREATISE ON GEMS. 
 
 93 
 
 pieces, and of gray-brown or red colour, and the form of which may 
 mostly be cut and polished in annular representations around its cen¬ 
 tre. It is found in Baden, Upper Egypt, and other places; among the 
 pebbles of the river Nile it is frequently discovered ; and in the year 
 1714, it was found near the village of Incheric by Paul Lucas. 
 
 b, Ribband, or Striped Jasper. It occurs in masses with nearly 
 conchoidal fracture, around which parallel straight or twisted stripes of 
 gray, green, yellow, red or brown colour may be perceived : it is 
 principally found in Siberia, East Indies, Corsica, Tyrol, and Hartz 
 mountains; also some of the West India islands produce most splendid 
 specimens. 
 
 Jasper is principally used for seals, snuff-boxes, vases, table-plates, 
 and for some architectural purposes. 
 
 When in lumps, it is divided by means of copper saws and fine 
 sand, and then cut on copper or leaden wheels with emery, and polished 
 on tin plates with rotten-stone, colcothar or charcoal; or it may first be 
 polished on wood with pumice-stone, and lastly on a tin plate with 
 rotten-stone and water. 
 
 The yellow Jasper is often employed in mosaic works in Italy, 
 and the striped Jaspar as cameos. The Jasper has no great value in 
 trade, except it be of exquisite quality, and fine objects made of the 
 same. It generally commands the best price in China, where the 
 emperor has a seal cut of it. A vase of red Jasper with white veins, 
 and one of black Jasper with yellow veins may be seen in the Yatican. 
 Chatouilles and other boxes of considerable size, are frequently found 
 in the jewellery stores of France, England, and the United States. 
 
 E, HORNSTONE. 
 
 Hornstone occurs massive, globular, stalactiforme, and in pseudo- 
 morphous crystals of the'carbonate of lime, and also in the form of 
 petrified wood (wood-stone or agatized wood). Its fracture is either 
 conchoidal or splintry, opaque or transparent on the edges; dull or 
 shining lustre; deep gray, brown, red, yellow, or green colour, and 
 rarely a pure colour. Often it has several colours in one and the same 
 specimen, such as points, spots and stripes. It scratches glass and 
 has a specific gravity of 2.53 to 2.65. 
 
 It is mostly found in gangues of the older formation ; also in the 
 old red sand stones and alluvial formations; in Bohemia, Saxony, 
 Sweden, Siberia, Hungary, and a number of other places; in the 
 old red sand, stone of Thuringia. I have traced one stem of the 
 red agatized wood of eighteen feet in length and two feet in diameter. 
 
94 
 
 TREATISE ON GEMS. 
 
 The price of the Hornstone is very small, and it is used for snuff¬ 
 boxes, seals, crosses, mortars, and principally as knife and fork handles, 
 which are now used by the silver-smiths to mount butter and dessert 
 knives and forks, and which are imported from Germany in conside¬ 
 rable quantities. 
 
 F, CHALCEDONY. 
 
 а, Chalcedony .—This mineral was held in great estimation by 
 the ancients, who received their principal supplies from Egypt and 
 other parts of Africa. In Rome, much use was made of it for 
 cameos, many of which may yet be seen in collections. The inha¬ 
 bitants of Iceland are likewise said to value it very highly, and to 
 attribute many medicinal properties to the same. It is found in 
 crystals, such as cubes, but mostly massive, botryoidal, stalactiform, 
 globular, or reniform, &c. The fracture is even, sometimes running 
 into conchoidal or splintry; is semi-transparent or translucent, of 
 little lustre or dull; of white, gray, blue, yellow, brown, or green 
 colours, which are all of a light shade andvariously figured, striped, 
 spotted, etc. 
 
 It scratches white glass, and has a specific gravity of 2.58 to 2,66. 
 It is distinguished by the following varieties, viz :— 
 
 1. Chalcedony proper, or Chalcedonyx, wherein white and gray 
 stripes interchange each other. 
 
 2. Moccha or Tree Stones, which are such Chalcedonies as display 
 black, brown or red dentritical figures. 
 
 3. Rainbow or Agate Chalcedony, is Chalcedony of thin and cen¬ 
 tric structure, and cut across and kept towards the light, displays an 
 iridescence. 
 
 4. Cloudy Chalcedony, light gray and transparent base with dark 
 and cloudy spots. 
 
 5. Plasma, dark grass-green. This mineral was very often em¬ 
 ployed by the ancients for cutting. 
 
 б. Semi-carnelcon or Ceregat, which is generally called the yellow 
 Chalcedony. 
 
 7. Sapphirine, which is the sky or sapphire blue Chalcedony. 
 
 8. St. Stephen’s Stones, is the white Chalcedony with blood-red spots. 
 
 There are many more varieties, and in my own collection I have 
 
 polished Chalcedonies, where, perhaps, as many again may be enu¬ 
 merated. 
 
 Chalcedony is found in gangues, and in the cavities of many rocks, 
 also in boulders and pebbles. Saxony, Hungary, Faroe Islands, 
 
TREATISE ON GEMS. 
 
 95 
 
 Ceylon, the shores of the Nile, Nubia, Nova Scotia; in the United 
 States, Connecticut, Massachusetts, Pennsylvania, Ohio, New-Jersey, 
 Missouri, Florida, and other countries are the localities of the same; 
 but the best specimens are brought from Oberstein, Iceland, and the 
 Faroe Islands. 
 
 The finer specimens are employed in jewellery, for rings, pins, brace¬ 
 lets, necklaces and seals; the more common is employed for snuff¬ 
 boxes, vases, buttons, &c. The larger lumps are cut by means of a 
 copper wire, with emery and oil on a copper wheel; it is polished on 
 a tin plate with rotten-stone, putty powder and pumice stone. The 
 cutting is generally done on a large scale like the agate. Many are 
 susceptible of receiving figures artificially, by means of the nitrate of 
 silver. Under Oriental Chalcedony is generally understood the better 
 qualities ; those Chalcedonies of two or three divisions, called Onyx, 
 are used for cameos. 
 
 The value of the Chalcedony depends on its quality, such as purity, 
 colour, and figures and drawings displayed on it; and among all the 
 varieties of Chalcedony, the Moccha stone stands the highest in price, 
 and also the Onyx, which is principally employed for making cameos, 
 and according to its size, commands a high or low price. Moccha 
 Stones are sold in France at from five to eight francs. The cabinet 
 of Dresden contains a plate of Onyx, about three inches broad and 
 long, which is estimated at twenty-five thousand dollars. 
 
 b, Carneleon. —-This stone was known to the ancients by the name 
 of Sarda ; which, according to some, is derived from a place in Lydia 
 or Sardinia, and according to others from the Arabic word sarda, 
 meaning yellow, and has been employed very frequently for cutting 
 intaglios or bas relief gems. 
 
 Carneleon occurs massive or in pebbles; its fracture is conchoidal; 
 resinous lustre; semi-transparent and translucent; of blood-red and 
 yellow, brown and yellow colour; frequently dark at the outside and 
 growing paler towards the inside; the colours are sometime changing 
 striated; scratches white glass ; has a specific gravity of 2.59 to 2.63. 
 There are two varieties known by the lapidaries and jewellers which 
 are better; those having a pale colour or yellowish tinge, or those 
 having a dark-red colour; the latter are in highest value, and are 
 called by the French Cornalines de vieille roche. 
 
 Sardonyx is called a Carneleon, having as its principal colour the 
 dark-brown or orange-yellow, and interchanged with layers of white 
 colour. 
 
 Carneleon Onyx, such as having a blood-red base interchanged 
 
96 
 
 treatise on gems. 
 
 with white stripes. The finest Carneleons come from Siberia, India, 
 Arabia, Nubia, Surinam, Oberstein in Germany, and Tyrol; mostly 
 as pebbles or in cavities of rocks; in the United States near Lake 
 Superior, Missouri and Massachusetts. The G'arneleon is used in 
 numerous articles of jewellery, such as seals, rings, watch-keys, &c.; 
 it is cut on a leaden plate with emery, and is polished on wood with 
 pumice-stone, and obtains its highest polish on a plate composed of 
 lead and tin with rotten-stone and water. The form of its cutting is 
 that of pavilion or step cut on the upper part, and either quadrangular, 
 hexagonal or octangular, or also round; and for raising its lustre or 
 colour it is furnished with a silver or gold foil, or with a red paint on 
 its base. The colour of the Carneleon is also improved by calcination; 
 the yellowish kind, for instance, by calcining it in a moderate heat 
 and cooling it slowly, may assume a good red colour. It is said that 
 ancients boiled the Carneleon in honey in order to heighten its colour. 
 Coloured figures or drawings may successfully be represented by a 
 mixture of white-lead, colcother, or other metallic ■oxides mixed with 
 gum-water, which is the material for drawing on it, and by burning 
 the same under a muffle. 
 
 The faults of the Carneleon are fissures, unequal colour and flaws 
 from other stones. The Carneleon is, on account of its being less 
 brittle, more useful for engraving and cutting cameos; and generally 
 the white layers are used for the figures of the cameos and the red for 
 the base. Sometimes such Carneleons which are cut with bas-relief 
 objects, are filled out with coloured Strass; and we receive from India 
 very frequently cameos with the most singular drawings, and which 
 are made by the inhabitants in the following manner: the whole 
 Carneleon is covered with carbonate of soda and then exposed to the 
 fire for a few minutes, whereby a Strass is formed, which serves for 
 cutting such figures. The value of the Carneleon is much higher 
 than any chalcedony, but yet depending on all its accomplishments 
 of colour, transparency, equal division of colour, or whether it is free 
 of any faults, such as fissures, clouds, dark spots, &c. For a perfect 
 Sardonyx a very high price is generally given, particularly when the 
 layers are very distinct and run quite parallel, and are pretty thick, so 
 that they are fit for cutting cameos or intaglios. The blood-red is 
 second in value, and the pale red third in price; but the cheapest are 
 the yellowish, brownish or whitish kinds; the prices vary from twenty 
 dollars to twenty cents per piece. There is a cameo of Sardonyx, 
 representing the portrait of the celebrated father Fontanarosa, having 
 its face white, with the base, cap and cloak black, so that it may dis¬ 
 tinctly show the Dominican monk. 
 
TREATISE ON GEMS. 
 
 97 
 
 8. HELIOTROPE, BLOODSTONE. 
 
 This stone derives its name from the Greek language, having been 
 used in ancient times for observing the sun ; and Pliny speaks, like¬ 
 wise, of the Heliotrope. It occurs in massive and obtuse angular lumps, 
 conchoidal fracture, translucent on the edges, resinous lustre, leak- 
 green colour, with red and yellow spots. It scratches white glass, has a 
 specific gravity of 2.61 to 2.63. The Heliotrope is found in the 
 Amygdaloid, in Tyrol, in the United States, (in New York, near 
 Troy), Scottish Islands, Siberia, Faroe Islands, Egypt, Barbary, 
 Tartary, &c. It is principally employed in rings and seals ; as gems, 
 watch-keys, snuff-boxes, and other articles of jewellery ; also for sword 
 and dagger handles, and is wrought like the Chalcedony, but some¬ 
 times cut on brass plates; and its forms are various, either en 
 cabocbon or en pavillion. 
 
 The Heliotrope has found great admirers in modern times, and the 
 price depends upon the colour and quantity of red spots contained in 
 the same. From one to twenty dollars is the usual price for good 
 specimens. 
 
 It is said that the superstitious people in the middle ages valued the 
 Heliotrope with many red spots, very high, thinking that Christ’s 
 blood was diffused in the Heliotrope stone. 
 
 9. AGATE. 
 
 This stone was well known to the ancients for the various purposes 
 of jewellery. In Rome it was principally used for cutting cameos 
 from the striped kind, the onyx. It has also been worn as an amulet, 
 with the different characters engraved in it. Its name is derived 
 from a river in Sicily, where the ancients procured it. The Agate is 
 a mixture of several species of quartz, which are combined variously 
 together; Chalcedony or Carneleon usually form the principal part, 
 and are mixed with Hornstone, Jasper, Amethyst, quartz, Heliotrope, 
 Cachelong and flint; and according to the predominating substances, 
 it is sometimes called Chalcedony, Jasper, or Carneleon Agate. Its 
 colour, as well as its other characters, depend upon the nature of the 
 mixed parts; likewise the hardness, hut it usually scratches white 
 glass, and has a specific gravity of 2.58 to 2.66 to the utmost. 
 
 According to the different figures represented in the Agate, it receives 
 its various names. 
 
 1st. Ribbond, or striped Agate, representing layers variously coloured 
 and changing with another. Onyx , or Agate Onyx are such Agates 
 the colours of which are beautiful and distinct, and the layers run 
 
 M 
 
98 
 
 TREATISE ON GEMS. 
 
 with the larger surface in a parallel form; whereas the common 
 Ribbond Agates display their various layers on their surface without 
 being parallel. If the stripes run together around the centre, it is 
 called the Circle Agate, and if in the same stone the centre shows 
 more coloured spots, it is called the Eye Agate, or Eyestone. 
 
 2d. Fortiftcational Agate is that brownish Agate, the various 
 coloured stripes of which run in zig-zag, or irregular angles, repre¬ 
 senting the ground plan of fortifications. 
 
 3d. Rainbow Agate; the curved stripes have the property of dis¬ 
 playing rainbow colours when held towards the sun, or candle light, 
 and the more distinctly if the stone is cut very thin. 
 
 4th. The Cloud, Landscape, Dentritic, Figure, Moss, Punctated, 
 Star, Petrifact, Shell, Coral, Tube, Fragment and Ruin Agates are 
 all the various forms the Agate is displayed in according to its figure 
 or drawing ; and a Ruin, or Fragment Agate may be pasted together 
 from the fragments of a common Ribbond Agate, and make it repre¬ 
 sent old walls, whereby it receives the name of Breccia Agate, and 
 sometimes the Rainbow Agate is in connection with the Shell Agate, 
 where the moss surrounding the petrified shells forms the Rainbow 
 Agate. 
 
 The Agate is found on gangues, gneiss or porphyry, and amygda¬ 
 loid; also as boulders and pebbles, in rivers, &c. It is found in Baden, 
 Oberstein, Saxony, Bohemia, Hungary, Faroe Islands, Siberia, West 
 Indies, and in ihe United States, (Massachusetts, Rhode Island, New 
 Jersey, Indiana, Missouri, Maryland, Georgia.) Those occurring in 
 the amygdaloid are mostly in the form of geods or balls, hollow at 
 the inside, and coated at the same time with quartz or amethyst; 
 and when the rock begins to disintegrate, these balls becoming loose, 
 fall scattering around the soil, and are then collected by persons who 
 make it a business of either selling or cutting them. 
 
 The Agate is used not only for the various purposes of jewellery 
 and ornaments, such as seals, snuff-boxes, crosses, cases of various 
 descriptions, ear-drops, &c. but also for numerous other useful 
 purposes, on a large scale ; such as slabs, mortars, vases, instruments, 
 knife and fork handles, playballs, &c. The mode and manner for 
 cutting the same, forms a considerable branch of the industry in a 
 part of Germany. The Agate, after having been assorted into large 
 and suitable lumps by means of a saw, chisel, or hammer, is then 
 cut on a copper wheel, by means of emery, powdered garnet or topaz, 
 and is afterwards polished on a tin plate, with rotten-stone, putty or 
 pumice-stone. 
 
TREATISE ON GEMS. 
 
 99 
 
 Oberstein, a small place in Rhenish Bavaria, in the north of 
 Germany, has five large manufacturing establishments for the sole 
 purpose of cutting and polishing the common gems or semi-precious 
 stones; and it is the only place where this branch of business is 
 carried to any great extent. Twenty mills are constantly driven by 
 water, and more than one hundred thousand dollars worth of work 
 is turned out yearly for export; a sum which is small in comparison 
 to the enormous quantity of goods manufactured and set afloat, but 
 pretty considerable for such places, where labour is so cheap, and the 
 best of workmen may be had for one dollar and fifty cents per week. 
 The works are carried on by means of water power. At Oberstein 
 the business is divided into two trades ; the one is devoted to the 
 cutting and polishing of the Agate, and the other to the boring; and 
 they are called the Agate lapidaries and the Agate borers. The 
 cutting is performed in the large Agate mills on sandstone; each 
 mill has generally five large sandstones, of five feet diameter, and 
 fourteen to fifteen inches in thickness, fastened upon a shaft, which 
 causes them to revolve vertically, and which are continually moisten¬ 
 ed by a stream of water. The workman leans with his body on a 
 peculiar bench, the seat of which is called the cuirass, and with his 
 feet presses himself against a pole, whence he continually pnsheS'the 
 larger lamps of the Agate towards the mill-stone; this, however, is 
 often made so smooth, from the friction, that it is necessary to make 
 it rough by knocking it with a sharp hammer, according to the kind 
 of work, whether fine or coarse. They are either polished on sand¬ 
 stone or on wood, by means of fine clay or powdered chalk; they 
 are polished sometimes, also on wooden wheels, covered with lead or 
 tin. Snuff-boxes and other articles of Agate which are hollow, are 
 polished on smaller sandstone wheels, which diminish in size as the 
 work advances. Agates which require to be bored, belong to a 
 particular branch, distinct from the other. The boring is performed 
 by means of a Diamond point, and as described by Mr. Maw. The 
 Onyx varieties are mostly employed for cutting cameos, and are pre¬ 
 pared there in such a manner that the darker layer is cut for the 
 base, and the lighter for the intended objects. 
 
 Next to Oberstein, in Germany, there is in Siberia, at Katherineburg, 
 a large manufactory for grinding and polishing the Agate and other 
 gems. Many varieties of the Agate are used for engraving other 
 stones, and also for the Florentine or stone mosaic work. Since the 
 Agate has always been, and is yet, a favourite stone, it has been 
 attempted to improve either its colour or other external appearance 
 
100 
 
 TREATISE ON GEMS. 
 
 by artificial or mechanical means; these are either by metallic solu¬ 
 tions or by boiling in oil of vitriol. The colour has often been im¬ 
 proved also by imparting to the stone before it is polished some strokes 
 in succession, the small fissures thereby produced display an iridescence 
 or other phenomena if held towards the light; this operation however 
 may easily be detected by wetting the stone, when the water, entering 
 into the fissures will destroy the effect; it will show itself again when 
 dry. On some Agates black and white layers are produced, in order 
 to use or sell them in the place of real onyx; this operation is per¬ 
 formed by the lapidaries, who boil certain varieties in oil of vitriol, 
 which turns some very soon into a black colour, and renders others 
 clear or still paler; the polished Agates are, however, only used for 
 this purpose, and the cause appears to lie in the oil absorbed by them 
 during the operation of polishing; on which account Agates are by 
 some first boiled in oil before submitting them to the operation of the 
 oil of vitriol. 
 
 The value of the Agate, although much reduced in comparison to 
 former days, and a good deal depending upon the purity and perfection 
 of colour and peculiar figures, commands a pretty good price in the 
 market; and it is particularly the Onyx which is yet at high sums, 
 and on that account the same is imitated by pasting thin plates of 
 Chalcedony, Jasper, Agate, &c. together, and make them by their 
 different colours appear like real onyx; this adulteration may however 
 be easily detected by putting it in hot water, which disengages the 
 plates one from another; the Onyx is likewise imitated by pastes, and 
 very happily, but may likewise be detected by the hardness and other 
 characters prominent in real stones. 
 
 The greatest collections of antique Onyx engraved as cameos and 
 entaglios are in Vienna and Berlin; in the first is to be seen the 
 apotheosis of Augustus, which is 10 lines broad and 6 high, and con¬ 
 tains twenty perfect figures ; this was purchased by the emperor Ru¬ 
 dolph at Frankfort on the Maine for fifteen thousand ducats. The 
 celebrated cameo in the Vatican Museum at Rome is of Agate, and 
 represents Augustus. Italy has always been the great emporium for 
 genuine antique Onyx and cameos, and occasionally we still behold 
 fine specimens of art from travellers coming from Europe. A very 
 fine collection of antique cameos and entaglios in precious gems and 
 antique pastes, likewise cameos and entaglios of modern artists I have 
 seen in this country in the possession of Thomas G. Clemson, Esq. 
 of Philadelphia. 
 
 I have in my collection a good Onyx of the emperor Vitellius, a 
 
TREATISE ON GEMS. 
 
 101 
 
 splendid cameo of Bacchus of two one-fourth inches long and one- 
 half inch thick, one of Anthony and Cleopatra, also a splendid en- 
 taglio. 
 
 In Paris are several celebrated cameos worth the notice of travellers 
 going to Europe; the Brunswick Vase, representing Ceres in search 
 of Proserpine; Agrippina and her two children, having two layers, 
 brown and white ; the quarrel of Minerva with Neptune, which has 
 three layers ; Venus on a sea-horse, surrounded with Cupids, &c. 
 
 Some modern works of cameo from the hand of the celebrated 
 Piickler are in the collection of Robert Gilmore, Esq. at Baltimore, 
 and in that of W. J. Lane, Esq. of this city. 
 
 10. CHRYSOPRASE. 
 
 The ancients by this name designated a stone of a green colour 
 with a yellowish tinge; but it is not certain whether that which goes 
 by this name at the present day is the same. We find in the fourteenth 
 century this stone used as ornaments in churches and other places; 
 but it was not known by that name until 1740, when it was discovered 
 by a Prussian officer in Silesia, and Frederick the Second has orna¬ 
 mented his palace Sansouci with the same mineral. 
 
 The common people of Silesia wear the Chrysoprase around the 
 neck as a charm against pains. 
 
 Chrysoprase occurs massive and in plates; the fracture is even and 
 splintery; is translucent; resinous lustre, sometimes dull. Apple-green, 
 grass-green, olive-green and whitish-green colour. It scratches white 
 glass distinctly, but is not so hard as true Chalcedony. Specific gra¬ 
 vity is 2.56, is infusible before the blow-pipe, but loses its colour when 
 heated. It consists of silex with a little carbonate of lime, alumina, 
 oxide of iron and nickle; its colour is imparted by the latter substance. 
 This mineral is found in the Serpentine of Silesia, also in Siberia and 
 in the United States in New-Hampshire. 
 
 Chrysoprase is used for various purposes in jewellery and ornament, 
 such as breast-pins, rings, bracelets, necklaces, seals, &c.; and the 
 larger lumps are used for snuff-boxes, cane-handles, table-plates, &c. 
 The cutting is pretty difficult, and the greatest care is required for 
 finishing the same with facets, as it easily receives fissures : it is 
 done on tin or lead plates with emery, keeping the first constantly wet 
 with water ; it is polished on a tin plate with rotten-stone, but the la¬ 
 pidary has always to be cautious not to let it become hot, as it easily 
 splinters, grows opaque and gray. The usual cut is the table or en 
 cabochon, with facets on the border; in setting, a foil of green satin is 
 
102 
 
 TREATISE ON GEMS. 
 
 often used for a back, but when pure and of good colour it is mounted 
 a jour. Inferior specimens are painted on the back with a mixture 
 of verdigris, white-lead and gum-mastic, or with sapgreen. 
 
 The Chrysoprase loses its colour by wearing, heat and sunlight 
 likewise cause it to fade, and render it dark and cloudy ; but the colour 
 may be restored by keeping it in a wet or moist place, such as a cellar, 
 in wet cotton or sponge, or even by dipping it in a solution of nitrate 
 of nickle, which serves likewise for improving inferior qualities. 
 
 Very line imitations in paste may be made by mixing to 
 1000 parts of Strass 
 
 5 ” of oxide of iron, and 
 
 8 ” of oxide of nickle. 
 
 The Chrysoprase is subject to a great many faults, such as fissures 
 either natural or received in cutting ; oily whitish spots ; pale gray 
 flaws and stripes, and sometimes small grains of clay of reddish colour 
 intermixed in the interior of the stone; but if pure, the Chrysoprase 
 has always been a great favourite. A good seal or ring-stone may be 
 worth from twenty-five to thirty dollars, and smaller specimens from 
 one to five dollars. The apple-green variety is most valued, and a 
 specimen of one line long by one-half broad has been sold at from 
 fifty to one-hundred and fifty dollars. At Paris, an oval Chrysoprase 
 of eight lines long' and seven lines broad was sold for three-hundred 
 and ten francs. The price generally has decreased of late on account 
 of the great quantity cut from the mines, which have lately been 
 covered up in order to raise its value again. At the Royal Palace of 
 Potsdam in Prussia are two tables of Chrysoprase, the plates of which 
 are three feet long, two feet broad, and two inches thick. 
 
 XIX. CHRYSOLITE. 
 
 The name of this stone is of Greek origin, and was well known to 
 the ancients, although it is undecided whether they understood the 
 same mineral by the same name as at the present time, for they bring 
 it in their writings to be either the Topaz or Goldstone, or the trans¬ 
 parent gold-yellow stone. 
 
 The Chrysolite occurs in prismatic forms, generally a right prism 
 with rectangular bases ; also in angular rounded crystalline grains or 
 massive; the fracture is conchoidal; it is transparent and translucent; 
 powerful double refracting power ; lustre is vitreous and resinous; the 
 lateral planes of the crystals are sometimes striated ; the colour is olive- 
 green turning to yellowish and brownish; it scratches glass indistinctly, 
 and is attacked by topaz ; its specific gravity is 3.33 and 3.44; be- 
 
TREATISE ON GEMS. 
 
 103 
 
 comes electric by rubbing ; is infusible by itself before the blow-pipe, 
 but is dissolved into a transparent pale green bead with borax; acids 
 do not affect it; it consists of magnesia, silica, and oxide of iron. 
 The Chrysolite is found particularly in the basalt, trapp, greenstone, 
 porphyry and lava, sometimes in alluvial deposits and the sands of 
 rivers; its principal localities are Brazil, Upper Egypt, Isle of Bourbon, 
 and Bohemia. 
 
 The Chrysolite is cut on a leaden wheel with emery, and is polished 
 on a tin plate with rotten-stone or oil of vitriol. Sometimes pale stones 
 are finally polished with some olive-oil, which raises the colour consi¬ 
 derably ; this last operation is applied to restore its lustre after the 
 Chrysolite becomes dull by wearing. The form is that of a rose or 
 table-cut, also en pavilion, and when set, gold-foil is used for its base; 
 the pale coloured Chrysolites look well with a green coloured copper- 
 foil ; dark Chrysolites may be rendered clearer by a careful calcination. 
 
 The Chrysolite is used for rings and pins, but does not stand in 
 high estimation, not possessing either a distinguished colour, strong 
 lustre, or great hardness, and losing its polish by wearing; on account 
 of its softness it wears off at the edges. Very good specimens of the 
 Peridote from Brazil were brought into this country from France, and 
 commanded a good price a few years ago, viz. from ten to fifteen 
 dollars a carat. 
 
 XXXI. IOLITE. 
 
 This mineral has for a long time been brought from Spain, but has 
 lately been made more known and brought into notice by Cordier, 
 and received its name Cordierite, likewise Steinheilite, and many 
 more names which I will mention in order, that the reader may not be 
 confused when the same mineral is brought as a gem under different 
 names : the most appropriate name is Dichroite , from its property of 
 displaying two colours when held in different directions; also Peliome 
 and prismatic quartz. 
 
 It occurs in regular six and twelve sided prisms, also in chrystaline 
 grains, massive and in pebbles; its fracture is conchoidal and uneven, 
 is transparent with indigo-blue colour when held towards its axis, or 
 transmitted light and brownish yellow when held at right angles; 
 possesses some double-refracting power ; sometimes a ray of light re¬ 
 sembling that of the Star-sapphire, may be perceived in the lolite, 
 particularly when cut; it has a vitrous lustre ; its colours are violet- 
 blue, indigo-blue, sometimes with a tinge of black and bluish gray. 
 It scratches glass, and is attacked by Topaz; its streak-powder is 
 
104 
 
 TREATISE ON GEMS. 
 
 white ; has a specific gravity of 2.88 ; by rubbing it becomes electric, 
 and assumes polarity by heating ; is difficult to fuse on the edges, and 
 becomes then a grayish green enamel, but borax dissolves it into a 
 diaphanous glass ; acids have no effect upon it; it consists of magne¬ 
 sia, alumina and silica, with some oxide of iron and water. 
 
 It is often found under the names of Lynx and water-sapphire, the 
 first of a pale and the latter of a darkish blue colour. It is found in 
 primitive rocks, also in blue clay, in copper pyrites, in quartz or fel¬ 
 spar, and in small detached masses ; the localities are Spain, Sweden, 
 Norway, Greenland, Siberia, Ceylon, Brazil, Bavaria and the United 
 States at Haddam, Connecticut. If the stone is perfectly pure, it is 
 used for rings and breast-pins ; is cut on a copper wheel with emery, 
 and polished on a tin plate with rotten-stone, and receives the form of 
 a cabochon, in order to let it display its proper colours in a cube form : 
 its price is not very high ; the jewellers value it as an inferior quality 
 of the Sapphire, without taking any regard for its phenomena of light. 
 Good sized specimens are sold at about eight to ten dollars a piece; at 
 Paris a good Iolite of 10 lines long and SJ, broad, was sold for one 
 hundred and sixty francs. When, a couple of years ago, the Iolite 
 was discovered by Professor Mather, at Haddam, Connecticut, it 
 promised to be a valuable acquisition for the American gems; but the 
 supply was very scant, and that, with its original locality appear to be 
 exhausted again. Professor Torrey possesses a fine seal in the form of 
 a cube, from that locality, which displays its properties to the greatest 
 perfection. 
 
 A blue quartz is occasionally sold for Iolite, but it may easily be 
 distinguished by its colours and hardness ; sapphire is also considerably 
 harder than the Iolite. 
 
 XIV. OPAL. 
 
 This mineral was known to the ancients by its precious variety, and 
 received its name on account of the play of colour. The Opal has a 
 great many varieties, which are all considered more or less gems, and 
 find their application in jewellery, they will therefore be treated sepa¬ 
 rately ; but as general character may now be mentioned, Opal scratches 
 glass but slightly, while it is marked by rock-crystal; it has a specific 
 gravity of 2.06 to 2.11. It is infusible before the blow-pipe, but de¬ 
 crepitates and falls in splinters ; it also dissolves with borax. Opal 
 consists of silica with water, some oxide of iron, and sometimes 
 alumina. 
 
TREATISE ON GEMS. 
 
 105 
 
 1. PRECIOUS OPAL. 
 
 This Gem derives its name from the Greek, the eye; for the 
 ancients believed that this stone had the power of strengthening the 
 eye. It was highly esteemed by them, as we learn from Pliny, who 
 thought that the play of colour originates from the beautiful colours 
 of the Carbuncle, Amethyst and Emerald. He also states that the 
 Roman Senator Nonius chose to suffer banishment, rather than part 
 with a valuable splendid Opal to Mark Anthony. A similar beautiful 
 large Opal was in modern times excavated from the ruins of Alexandria. 
 
 The phenomenon of play of colours of the Precious Opal has not 
 yet been satisfactorily explained. Haiiy attributes it to the fissures of 
 the interior being filled with films of air, agreeably with the law of 
 Newton’s coloured rings, when two pieces of glass are pressed together. 
 Mohs contradicts this theory, upon reasonable grounds, which are, 
 that the phenomenon would present merely a kind of irridescence. 
 Brewster concludes that it is owing to the fissures and cracks in the 
 interior of the mass, not accidental but of a uniform shape, and 
 which reflects the tints of Newton’s scale; but it is, in my opinion, 
 too plausible, that the unequal division of smaller or larger cavities 
 which are filled with water, produce the prismatic colours, and for the 
 simple reason that the Opal that grows, after a while, dull and 
 opaque, may be restored when put for a short time in water or oil. 
 
 Although the Precious Opal was never found in the East, yet it 
 bears the name of Oriental Opal among the jewellers; for in former 
 times the Opals were carried by the Grecian and Turkish mer¬ 
 chants from Hungary, their native locality, to the Indies, and were 
 brought back by the way of Holland to Europe as Oriental Opals. 
 The Precious Opal is found on small irregular gangues, nests of the 
 trachytic porphyry formation, and its conglomerates, in Hungary, 
 particularly in the neighbourhood of the village of Czerwinceza; 
 also in the Faroe Islands, Saxony and South America. The 
 Hungarian Opal is found in its various qualities, and obtained in 
 mines which have been wrought for several centuries ; and according 
 to the archives of that part of the country, there were, in the year 
 1400, more than three hundred workmen engaged at the mines near 
 the above village; whereas there are but thirty at present engaged 
 there, on account of the scarcity of larger suitable specimens. 
 
 The Precious Opal is principally used for rings, ear-rings, necklaces 
 and diadems ; the smaller specimens for mounting snuff boxes, rings, 
 chains, &c. It is ground on a leaden wheel with emery, and is 
 polished with rotten-stone and water on a wooden wheel; and in order 
 
 N 
 
106 
 
 TREATISE ON GEMS. 
 
 to increase its lustre it is lastly rubbed with putty by means of buck¬ 
 skin or a woolen rag and red chalk. Its form is generally that of 
 semicircle, lens or oval; sometimes of a table, and then also with 
 some facets ; but then great care has to be taken that the edges, on 
 account of the softness of the stone, will not wear off’. It is also apt 
 to spring in a temperature suddenly changing. When mounted it 
 receives a coloured foil, or a variegated silk stuff, or a peacock feather 
 on the back, but it looks best in a black casing. 
 
 Cracks and fissures may be removed by leaving the Precious Opal 
 for some time in oil. Very frequently tire Precious Opal is distributed 
 in small particles in the matrix, called Mother of Opal, which is cut 
 by the jewellers as boxes, and other ornaments; and very often too 
 this matrix is plunged in oil, and is exposed to a moderate heat, 
 whereby the base grows blacker, and the true Precious Opal retains 
 its ray of colours. In order to preserve the surface of the Precious 
 Opal against wear and tear, it is covered with a thin plate of quartz- 
 crystal. The Precious Opal still stands in very high estimation, and 
 is considered one of the most valuable Gems; the size and the beauty 
 displayed by its colours determine its value; those playing in the 
 red and green colours bear the highest price. Its value has latterly 
 increased on account of the scarcity of the larger specimens. 
 Formerly a solitary large Precious Opal, playing in the red colour, 
 was sold for two to three hundred ducats; and one playing in both 
 red and green colours, of about five lines long, was sold at Paris for 
 two thousand four hundred francs ; and lately a single Opal, of fine 
 colours, and the size of a dollar, was sold near the locality for three 
 hundred thousand florins; but in this country the Precious Opals are 
 sold by the importers at the rate of four to ten dollars per carat, and 
 single specimens, suitable for pins or rings, from two to twenty dollars. 
 The mother of Opal is, however, much cheaper; one of five lines 
 size is sold for three to five dollars. 
 
 All experiments for imitating the Precious Opal have hitherto 
 proved fruitless ; they were either by preparing an enamel and adding 
 several metallic oxides, or by affixing to the back of a clear or com¬ 
 mon Opal or Enamel, a polished thin plate of the mother-of-pearl, 
 which may sometimes deceive the ignorant. 
 
 The imperial mineralogical cabinet at Vienna, contains the most 
 distinguished specimens of Precious Opal; one particularly, may be 
 mentioned here, which is the largest known: it is four and three- 
 quarters inches long, two and a half inches thick, and weighs seven¬ 
 teen ounces. It was discovered about 1770, at the above locality, 
 
TREATISE ON GEMS. 
 
 107 
 
 and transported to Vienna. It displays the most magnificent colours ; 
 is perfectly pure, and not accompanied by any matrix. Half a million 
 of florins were offered for it by a jeweller of Amsterdam, and refused 
 on account of its unity; and the Viennaians have not yet dared to 
 put even any approximative value upon it. 
 
 2. FIRE OPAL. 
 
 This mineral was first brought into notice by Baron Humboldt, 
 who found it in Mexico. 
 
 It occurs massive; has a conchoidal fracture; is transparent; of 
 strong vitreous lustre; hyacinth red, running into honey; wine yel¬ 
 low ; showing carmine-red and greenish reflections; sometimes con¬ 
 taining dentritic drawings. Its specific gravity is 2.02 ; loses one and 
 a half per cent, by calcination, and leaves pale flesh-red fragments. 
 It is found in the trachytic porphyry, in Mexico, and in the amygda¬ 
 loid of the Faroe Islands. 
 
 Since the Fire Opal is very little known, it has not yet been 
 employed in jewellery, but bids fair to find applications. It is ground 
 on a leaden wheel with emery, and polished with rotten-stone on a 
 wooden wheel. The forms of cabochon, table, or pavillion, might 
 suit very well as ring-stones, 
 
 The cabinet of the University of Bonn possess a very large and 
 fine Fire Opal, of the size of a fist. The largest specimen I have 
 seen is in the Mineralogical Cabinet at Berlin, which was deposited 
 by Baron de Humboldt on his return from South America, and which 
 if I reccollect it well enough from the year 1827, must be at least six 
 inches long and four inches thick. This is the largest specimen he 
 ever found. A collection of six shades of Fire Opal, with six more 
 varieties of the other Opals was presented to me in the year 1828, 
 when in Berlin, by the Counsellor Bergeman, who received at that 
 time a considerable quantity of polished specimens from the Faroe 
 Islands, but all of small size. A splendid collection of Fire Opals 
 was brought from Guatimala some years ago to this country. 
 
 3. COMMON OPAL. 
 
 This mineral occurs massive and in rolled pieces ; also as 
 stalactites; has a conchoidal fracture; is translucent and semi-trans¬ 
 parent ; has a strong vitreous and resinous lustre; its colours are 
 milky, yellow, reddish, greenish-white, honey-yellow, wine-yellow, 
 flesh, red-brick and olive-green; sometimes dentritic (Moss Opal) 
 Its specific gravity is 1.9 to 2.1. 
 
108 
 
 TREATISE ON GEMS. 
 
 The Wax and Pitch Opal are subordinate to this variety. It is 
 found in the same rocks as the Precious Opal, in Hungary ; in the 
 hematite rocks of Saxony ; in the Serpentine of Silesia ; in cavities 
 of trapp and the amygdaloid rocks of Iceland ; Faroe Islands ; and 
 in the United States, (Pennsylvania and Connecticut.) 
 
 It is used for rings, pins, and cane heads ; but is on the whole not 
 a favourite among the jewellers, and has no great value, because it is 
 soft and brittle; the paste, which may be made from white enamel, 
 is sometimes much prettier than the real stone. 
 
 4. HYDROPHANE. 
 
 The name of this variety of Opal relates to the peculiar property 
 of becoming transparent, and opalescent after immersion in water. 
 The ancients called this stone lapis mutabilis, and achates oculus 
 mundi. It is a common or precious Opal, of porous texture ; adheres 
 strongly to the tongue ; is translucent, and absorbs water with 
 avidity, giving off at the same time air bubbles ; it thus assumes a 
 high degree of transparency, and sometimes the property to play the 
 finest prismatic colours, equal to the Precious Opal. This phenome¬ 
 non tends strongly to explain the display of the prismatic colours of 
 the Precious Opal; the more so as the Hydrophane loses this property 
 on getting dry. 
 
 It has, when dry, a white, yellowish, or reddish colour; has a 
 specific gravity of 1.95 to 2.01; and according to Haiiy, a Hydro¬ 
 phane having been immersed for four minutes in water, thirty-four 
 centigrammes. 
 
 The Hydrophane is found in the porphyry of Hungary, France, 
 Iceland and Faroe Islands. Large lumps, of good and fine speci¬ 
 mens of Hydrophane are wrought and used in the same manner as 
 the Precious Opal. 
 
 It is said that the Hydrophane becomes much quicker transparent 
 in warm than in cold water; the quickest in spirits of wine, when it 
 looses this property the sooner, but retains some for years when 
 boiled in oil. 
 
 If the Hydrophane is well dried and soaked in melting white wax, 
 or spermaceti, it assumes the property, when warmed, to become 
 translucent, and to display brownish-yellow or gray colours, and is 
 then called Pyrophane. 
 
 The Hydrophane was once coloured violet or red, by means of a 
 decoction of logwood and alumn. 
 
TREATISE ON GEMS. 109 
 
 The price of the Hydrophane is very high, on account of its great 
 scarcity, and because it is very seldom found in large lumps. 
 
 5. SEMI-OPAL. 
 
 This specimen of Opal was formerly considered to be a pitch stone, 
 and if it assumes the form of petrified wood, it is called Wood Opal. 
 It has a conchoidal and even fracture; it is translucent and opaque; 
 resinous and vitreous lustre ; its colours are yellowish, grayish, 
 and brownish, the colours running mostly in one another ; sometimes 
 the colours divide themselves ribband-like. The Wood Opal is 
 mostly brownish, and displays, more or less, a ligneous aspect, with 
 the forms of asts, or branches. 
 
 The Semi-Opal is found on gangues, in the trachytic porphyry in 
 Hungary, in the serpentine in Silesia, in the Amygdaloid on Iceland 
 and the Faroe Islands ; likewise in Moravia, Saxony, France, Green¬ 
 land ; and in the United States, (Maryland and Pennsylvania.) 
 
 The Semi-Opal, on account of its taking a high polish, is used for 
 many purposes in jewellery. There is an establishment for manufac¬ 
 turing snuff-boxes from Wood Opal, in Yienna, and lately the 
 varieties of Wood Opal, with layers of Chalcedony, or Semi-Opal, 
 have found a useful application in the cutting of Cameos. The 
 Semi-Opal is ground and polished like the Precious Opal, but with 
 more difficulty, on account of its being more brittle. The form 
 which it quickly receives is en cabochon, but without facets. The 
 price of the Semi or Wood Opal is low. 
 
 6. CACHELONG. 
 
 According to Blumenbech, the name of this mineral is of Mongolian 
 derivation, and meaning “ a pretty stoneand according to Philipps 
 it bears its name after the river Cach, in Bucharia, on whose shores it 
 occurs frequently in loose conglomerates. This mineral was hitherto 
 arranged under the head of Chalcedony, but properly belongs to Opal. 
 
 It occurs massive, as a covering of other minerals, rarely reniforme, 
 often transpersed with fissures in different directions. It has a 
 conchoidal fractue; is opaque, and of a pearly lustre ; milky-white, 
 turning sometimes to yellow or red colour; with dentritic figures of 
 manganese, or green earth. It scratches white glass ; has a specific 
 gravity of 2.2; it decrepitates when first brought before the blowpipe, 
 but yet undergoes no change; dissolves with borax, slowly, to a 
 white heat. 
 
 It is found in the same manner as the Chalcedony, sometimes 
 
no 
 
 TREATISE ON GEMS. 
 
 encrusting or penetrating it; in the amygdaloid of Iceland, Greenland 
 the Feroe Islands, the Hematite of Corinthia, the United States, 
 (Massachusetts,) Nova Scotia; and in Buchary, in the sand of the 
 river Cach, it is found loose. 
 
 Cachlong is much used in jewellery for rings, seals, &c. The 
 Calmucks of the Bucharia manufacture of it tools and other domestic 
 articles. It is cut on a copper wheel with emery, en cabochon, and 
 receives the polish on lead plates, by means of rotten-stone and putty. 
 The price of the Cachelong is pretty considerable, on account of its 
 beauty and scarcity ; as the specimens most frequently found in the 
 above localities are seldom in layers of more than one-quarter lines, 
 interchanging with the Chalcedony. 
 
 7. JASPER OPAL. 
 
 This mineral stands between the Jasper and Opal; and, although 
 considered by Werner as belonging to the first, ought, nevertheless, 
 to be more properly arranged to the Opal, on account of its containing 
 water in its composition. 
 
 The Jasper Opal occurs massive, in specks, stalactiform, in geody 
 masses ; has a conchoidal fracture; is translucent on the edges, or 
 opaque; of strong resinous lustre; its colours are gray, yellow, red 
 and brown. Its specific gravity is 2.0 to 2.1. It consists of silica, 
 water and oxide of iron, amounting to forty-seven per cent. It is 
 found in the trachytic breccias of Hungary, also in Saxony and 
 Siberia. The best light and pure specimens are used for dagger and 
 sword handles in Turkey. The price of Jasper Opal is low. 
 
 xv. OBSIDIAN. 
 
 This mineral was very familiar to the ancients, and its name is 
 said to be derived from a Roman, who first brought it to Rome from 
 Ethiopia. Pliny states that the Romans manufactured mirrors and 
 gems from it; and the Mexicans and Peruvians manufactured their 
 knives, razors and sword blades from the Obsidian, which appears to 
 have served as a complete substitute to those nations who were yet 
 unacquainted with the use of gems as weapons and utensils of 
 various purposes. The Baron Humboldt says, that Cortez mentioned 
 in his letter to the Emperor Charles V., of having seen razors of 
 Obsidian at Tenochittan; and the above naturalist likewise discov¬ 
 ered, himself, on the Serro de las Nabajaz, in New Spain, the old 
 shaft what was used for raising the rough Obsidian, with relics of 
 the tools and half finished utensils. 
 
TREATISE ON GEMS. 
 
 Ill 
 
 The inhabitants of Quito manufactured magnificent mirrors from 
 Obsidian, and those of the Astor and Assencion Islands, and Gueiana 
 used splinters of the Obsidian as points for their lances, razors, &c. 
 
 Specimens of arrows and other articles, such as octangular wedges, 
 were presented a few years ago to the New York Lyceum of Natural 
 History, as relics from the ruins of Palanque. In the collection of 
 Columbia College are some razors, or sacrificial knives, the gift of the 
 Hon. J. R. Poinsett. 
 
 Obsidian occurs massive, in roundish or obtuse lumps, balls and 
 grains; has a conchoidal fracture; is semi-transparent and translu¬ 
 cent on the edges; strong vitreous, and sometimes even metallic 
 lustre ; its colours are either pure black, grayish, brownish, greenish- 
 black, yellow, blue or white, but seldom red ; it sometimes displays a 
 peculiar greenish-yellow shine, when it is called the iridescent Obsi¬ 
 dian ; but there are rarely more than one colour in the same speci¬ 
 men with stripes and specks. Obsidian scratches white glass indif¬ 
 ferently, but is scratched by Topaz; its streak powder is white; has 
 a specific gravity of 2.34 to 2.39. Obsidian is sometimes magnetic, 
 so that small pieces show their magnetic poles. Before the blowpipe 
 the black variety is fusible with much difficulty ; and at white heat 
 it does not even melt into a solid glass; but the gray and brown 
 variety (Marekanite) swells readily into a spongy mass. 
 
 Obsidian consists of silex, alumina, with a little potassa, soda and 
 oxide of iron. 
 
 The names Iceland Agate, lava, black glass lava, volcanic lava, 
 are all synonymous, and the mineral called Bottlestone, in round 
 grains of the size of a pea, is nothing but a green Obsidian. 
 
 The Obsidian, sometimes, forms the cement of whole mountain 
 chains, often deposites in the Trachyt and the streams at the foot of 
 some volcano ; also among the volcanic ejections, and in loose lumps 
 in the sand of rivers, and at the foot of mountains. It is found in 
 Iceland, Teneriffe, Lipari Islands, Peru, Mexico, Sicily, Hungary, 
 Asiatic Russia, Assencion Islands, and on all the volcanos of former 
 and present times. 
 
 In the New York Lyceum of Natural History are several interest¬ 
 ing specimens, presented by Don Correa, of Tobasco, coming from 
 the ruins of the city of Palanque; such as concave, or triangular 
 wedge, and other masses of Obsidian from various other localities. 
 
 It is used for several purposes in jewellery; such as ear-rings, 
 necklaces, broaches, snuff-boxes, knife handles, &c. It is particularly 
 worn as mourning jewellery; it requires, however, much care in 
 
112 
 
 TREATISE ON GEMS. 
 
 working it, being extremely brittle. It is ground on lead wheels with 
 emery, and polished with rotten-stone. It is kept in favour of the 
 jewellers on account of its high polish ; but its value is very indiffer¬ 
 ent, except the iridescent Obsidian, which commands a high price, 
 and is sometimes seen cut en cabochon, and set in rings. 
 
 There is no doubt but what Obsidian is of volcanic origin, being 
 mostly found in the neighbourhood of volcanos, and that it is a 
 glass, produced by the volcanic fire, as it is a combination of silex 
 and alcaline substances. The Neptunic theorists have endeavoured 
 to prove that it is occasionally found with the remains of decomposed 
 granite, gneiss and porphyry, with which it even alternates in layers. 
 
 XVI. AXINITE. 
 
 The name of this mineral is derived from the Greek, meaning an 
 axe, on account of the resemblance of its crystals to a hatchet; it is 
 also called by some English mineralogists Thumerstone, on account 
 of its first locality. The Axinite occurs in a variety of crystaline 
 forms, to be reduced to the rhombic forms, viz: an oblique rhomb, 
 or four sided prism, so compressed that the edges appear sharp, like 
 the edge of an axe; likewise massive and in specks; fracture 
 uneven; is translucent on the edges, or transparent; has a simple 
 refraction of light; lustre is vitreous, also resinous; its colours are 
 violet-blue, brown, gray and yellow ; scratches white glass, but is 
 scratched by Topaz ; has a white streak powder ; its specific gravity 
 is 3.27; becomes electric by rubbing or heating ; before the blowpipe 
 it fuses into a grayish-brown glass ; acids have no effect upon it; it 
 consists of lime, alumina and silex, with oxide of iron and manganese. 
 It is found on gangues and layers of various formations, principally 
 the primitive ; is found in the Dauphinee, Pyrenees, Gothard, Saxony, 
 (Thum) Norway, &c. 
 
 This mineral takes a very high polish, particularly those from the 
 Dauphine, but has hitherto, on account of its scarcity, not found 
 much application in jewellery, but will hereafter make a great acqui¬ 
 sition, as it may be used for rings, pins, and other small ornaments. 
 
 XVII. FELSPAR. 
 
 The varieties of this mineral are mostly chrystallized, and in very 
 numerous forms ; but they are all distinguished by two great charac¬ 
 ters, which are, the foliated structure and peculiar lustre ; the principal 
 form is an oblique prism with unequal sides. Felspar scratches glass 
 and is scratched by rock-crystal; its streak-powder is white, has a 
 
TREATISE ON GEMS. 
 
 113 
 
 specific gravity of 2.5 to 2.6 ; before the blow-pipe it fuses with diffi¬ 
 culty ; on the charcoal it becomes vitreous and white; fuses with 
 difficulty on the edges to a translucent white enamel; the acids have 
 no effect; it consists of potash, alumina and silex. 
 
 1. ADULARIA. 
 
 This mineral occurs in crystals, crystalline fragments, and solid 
 masses; its fracture is uneven; is translucent on the edges, with 
 double refraction of light ; the lustre is vitreous and pearly, more 
 especially when cut and polished ; it throws out greenish and bluish 
 white chatoyant reflections from the interior ; it cleaves in two direc¬ 
 tions ; the crystals often present the hemitrope form, which in polished 
 specimens becomes obvious from the different directions of the laminae; 
 its colours are limpid white, greenish, grayish, and bluish, frequently 
 with a peculiar pearly shine, and sometimes irridescent. 
 
 In commerce the Adularia goes under various names, such as 
 Moonstone, Sunstone, Girasol, Fisheye, Ceylon or Water Opal. In 
 the Moonstone the colour is white, with small bluish or greenish shades, 
 but the base is semi-transparent and milky ; whereas the Sunstone 
 shows a yellow and reddish play of colours. The Adularia is found 
 in gangues and cavities of the granite and gneiss, and limestone, and 
 in pebbles from Ceylon, Greenland, Bavaria, St. Gothard, Tyrol, 
 Dauphinee, and in the United States, particularly at Ticonderoga, 
 New York, near Lake Champlain, Maryland, Pennsylvania, Connec¬ 
 ticut, and Massachusetts. The Adularia from St. Gothard is found 
 in very large masses ; and I have seen, in 1827, in the cabinet at 
 Zurich, in Switzerland, groups of crystallized Adularia, measuring 
 two feet in length, and one foot in thickness, which for splendour 
 dazzled my eyes. 
 
 Adularia, displaying a good colour, and strong pearly reflections, is 
 much used now in jewellery, for rings, pins, and other smaller orna¬ 
 ments. Generally specimens which possess these qualities are cut out 
 of larger lumps, then ground on a lead wheel, en cabochon form, and 
 polished with rotten-stone; they are in general mounted in a black 
 case, whence it best shows its reflections. The Moonstone commands 
 a good price; exquisitely fine specimens of the size of a bean, are 
 worth from five to ten dollars, and some of them were sold at Paris, of 
 six lines diameter, for seven hundred and five francs, and four lines for 
 two hundred and three francs. 
 
 The largest Moonstone, in a brooch, of three-fourths of an inch 
 in length, I have seen in the possession of Francis Alger, Esq. of 
 
 o 
 
114 
 
 TREATISE ON GEMS. 
 
 Boston ; and rough specimens, with most splendid reflections, 1 have 
 admired in the collection of Dr. M. Gay, in the same city. Both these 
 gentlemen are fortunate in possessing uniques in this country, which 
 are of no ordinary scientific and commercial value. 
 
 2. COMMON FELSPAR. 
 
 This Felspar occurs in crystals, massive and disseminated; fracture 
 uneven and splintry ; translucent; pearly and vitreous lustre; its 
 colours are white, gray, red, yellow and green, in their various shades, 
 sometimes with variegated bluish, greenish or reddish play of colours: 
 its texture is compact, or minutely foliated. 
 
 The Amazon Stone, or green Felspar, is from Siberia; likewise 
 were found splendid grass-green Felspar in the United States, at 
 Southbridge and Hingham, Massachusetts, and Cow-Bay, New York; 
 of apple-green colour at Topsham, Maryland, and near Baltimore. 
 Also the American glassy or vitreous Felspar from Delaware, which 
 latter ought properly to be quoted as a distinct species, belong to this 
 variety. 
 
 Felspar is widely diffused all over the globe, and with a few ex¬ 
 ceptions is more common than any other mineral; it forms a consti¬ 
 tuent part of most primitive rocks, such as gneiss, granite, &c. ; is 
 the principal ingredient of the Synites, Porphyry, and, in fact, with a 
 small per centage of other minerals, forms whole mountain ranges and 
 chains in various parts of the globe ; such we see in Siberia, the north 
 and west of Scotland, &c., all which are surrounded by Felspar. 
 Immense beds exist in the United States. Around Wilmington in the 
 State of Delaware, is an inexhaustible deposit of exquisite and per¬ 
 fectly pure Felspar; and in Connecticut and on the North River we 
 see beds of the foliated Felspar extending for miles : Sweden, Nor¬ 
 way and Greenland are likewise great depositories for the common 
 Felspar. 
 
 The Amazon stone is used in jewellery for rings, pins, seals, snuff¬ 
 boxes, &c. It is principally cut at Katharineburg, Siberia, where it 
 is ground on a leaden w T heel with emery, and polished with rotten- 
 stone on a wooden wheel; its form is that of en cabochon, sometimes 
 the mixed and pavilion cut, then the table is to be cut pretty large, and 
 arched, in order to display more distinctly its peculiar colours. 
 
 Common Felspar is of no great value, and only the Amazon stone 
 is used in jewellery, which commands a good price. Cut specimens, 
 suitable for ear-rings or brooches, are worth from three to five dollars. 
 
 A very fine specimen of the Amazon stone in its rough state, may 
 
TREATISE ON GEMS. 
 
 115 
 
 be seen in the New York Lyceum of Natural History. The imperial 
 cabinet of St. Petersburg 1 possesses two vases of this stone, which are 
 nine inches high and five and one half inches in diameter. Although 
 our vitreous Felspar has not yet been brought into use for the purposes 
 of jewellery and other ornaments, yet it bids fair to contribute at one 
 day, much to the national wealth of this country, for it is the best ma¬ 
 terial for porcelain, china and earthenware. Already have many 
 cargoes of this beautiful mineral been shipped to France and England, 
 (six hundred tons of the Connecticut, Middletown, Felspar, were, ac¬ 
 cording to Professor Shephard, last year shipped to Liverpool, and one 
 hundred tons to the Jersey porcelain manufactory,) where the manu¬ 
 facturer appears to appreciate better the purity of ingredients for the 
 purposes just mentioned ; and instead of receiving, as hitherto, the 
 manufactured goods from abroad, made of our own raw material, it 
 is seriously to be hoped that we shortly will muster skill and industry 
 enough to compete in the art of making porcelain with the superior 
 material nature appears to have provided this continent. I possess a 
 splendid slab of the vitreous Felspar of one square foot, free from any 
 admixture, and imposing in appearance. 
 
 XVIII. LABRADOR. 
 
 This mineral was hitherto considered as a variety of Felspar ; but 
 has latterly been separated from it, and ought, therefore, no more be 
 called the Labrador Felspar, the name by which it is specified in all 
 the mineralogical works. 
 
 The Labrador was first discovered by the Moravian missionaries on 
 the island of St. Paul, on the coast of Labrador; and according to 
 others, by Bishop Lauritz, in 1775, when it was brought to Europe. 
 The Labrador occurs in crystalline masses, massive, and in boulders; 
 uneven and conchoidal fracture; the lustre is vitreous, and in one 
 direction pearly; translucent; its colours are gray, with its various 
 shades, such as blackish or whitish gray, with spots of opalescent or 
 irridescent vivid play of colours, consisting of blue, red, green, brown, 
 yellow or orange, according to the direction the light is falling upon 
 the specimen; sometimes several of these colours are perceptible at the 
 same instant, but more commonly they appear in succession as the 
 mineral is turned towards the light. These colours are said to origi¬ 
 nate in fissures which intersect the texture of the mineral, as they are 
 only perceptible from that side where they fall together with the foliated 
 structure, and not like the Opal, whose mass is supplied with fissures 
 running through all directions. 
 
116 
 
 TREATISE ON GEMS. 
 
 The Labrador scratches white glass, is scratched by rock-crystal, is 
 somewhat less hard than Felspar; its specific gravity is 2.71 to 2.75 ; 
 before the blow-pipe it fuses with difficulty, and is said to lose its play 
 of colours ; it consists of silex, alumina, lime, soda, with some oxide 
 of iron and water. The Labrador is found as a rock and boulder, in 
 St. Petersburg, Norway, Bohemia, Saxony, Sweden, St. Paul’s island 
 on the coast of Labrador, and in the United States, in Essex county, 
 New Jersey, on the mouth of the North River, and near Lake Cham¬ 
 plain, New York, where, according to the description given me by 
 Archibald McIntyre, Esq. its splendid colours are seen on both sides 
 of the river, but a few yards apart, and the rays of the morning sun 
 falling upon the rock and river at the same time, are said to equal the 
 prismatic colour thrown in a dark room. 
 
 The Labrador is used for rings, pins, buttons, snuff-boxes, letter 
 holders, cane heads, and other ornaments, such as vases and larger 
 utensils; but care has to be taken in grinding, that the direction where 
 the play of colours is visible is kept straight, and that it is cut en 
 cabochon. The price of the Labrador is not very high, but soon after 
 its discovery, a Doctor Anderson having described the mineral as 
 displaying all the variegated tints of colour that are to be seen in the 
 plumage of the peacock, pigeon, or most delicate humming bird, and 
 specimens having been brought to England, so great was the avidity 
 to possess it, that small pieces were sold for twenty pounds sterling. 
 The present price of good specimens is from two to ten dollars; and 
 a few years ago I purchased some letter-holders, which are beautiful 
 specimens, for which I paid four dollars a-piece. The largest speci¬ 
 mens of Labrador are in the collections of the Mineralogical Society, 
 and in the museum of the Academy of Sciences at St. Petersburg, 
 which were found on the shore of the Pulkouka; one of them weighs 
 ten thousand pounds. I have in my possession a rough specimen of 
 the Labrador of this State, merely rubbed off on the surface, and its 
 colours, I venture to say, compete in every respect with that from St. 
 Paul’s island, if not superior ; and I anticipate the day when the citi¬ 
 zens of New York will find a glory in possessing Labrador table and 
 mantel slabs, in tire same ratio as the Italian and Irish marble is now 
 generally employed ; for the resources appear to be inexhaustible in 
 that rocky county of Essex. We do not see many specimens brought 
 from the coast of Labrador, and I was informed by Mr. Audubon, on 
 his return from that quarter, that he could not detect any specimens. 
 Mr. Henderson, of Jersey City, who presented me the above rough 
 specimen of Labrador, had likewise splendid small polished specimens 
 
TREATISE ON GEMS. 
 
 117 
 
 in breast-pins, displaying all the elements in their full beauty. The 
 same gentleman, who travelled last summer in company with several 
 scientific State geologists, states that they picked up beautiful specimens 
 at the height of five thousand seven hundred feet above the level of 
 the sea. 
 
 In the collection of Columbia College is a fine specimen of Labrador, 
 brought fromGaspy, Lower Canada, by the Hon. Mrs. Percival. 
 
 XIX. HYPEESTHENE. 
 
 This mineral was formerly annexed to Hornblende, but has latterly 
 been separated ; its name is derived from the Greek, meaning “ above 
 the stone,” in reference to the great hardness and specific gravity 
 which it possesses. 
 
 The Hypersthene is found in crystalline masses; has an uneven 
 fracture; is opaque, and the colours are dark brown, red, greenish or 
 grayish black ; cleavage parallel to the sides, and shorter diagonals of 
 a rhombic prism ; its lustre is metallic, and when viewed in one cer¬ 
 tain direction, copper-red, light brown, or gold-yellow, and in others a 
 greenish play of colours. It scratches glass, has a darkish green 
 streak-powder,” and has a specific gravity of 3.38; is easily fusible 
 before the blow-pipe on charcoal to a grayish dark bead ; acids have 
 no effect, and it consists of magnesia, silex, alumina and lime, with 
 some water. 
 
 It is found forming a constituent of the Labrador rock, on the coast 
 of Labrador, Greenland, and in the United States, on Brandywine 
 Creek in Pennsylvania, and in Essex county, New Jersey; fine spe¬ 
 cimens have been found in Hingham, Massachusetts. The French 
 jewellers have lately begun to introduce this mineral for rings, pins, 
 and other ornaments, on account of its high polish and beautiful colour. 
 The best coloured pieces are cut out of the mass, and ground on a 
 lead wheel with emery en cabochon, and polished with rotten-stone. 
 Beauty of colour and other qualifications determine the price of this 
 stone; at Paris a Hypersthene, en cabochon cut, and of 8 to 10 lines 
 long and 6 lines broad, was sold for one hundred and twenty francs. 
 
 The mineral is, however, pretty rare, and has not yet been fully 
 introduced. 
 
 XX. IDOCRASE. 
 
 This mineral occurs mostly crystallized in the form of a four-sided 
 prism, terminated by four-sided pyramids, also massive; cleavage 
 parallel to all the planes of the prism; is transparent and opaque ; 
 
118 
 
 TREATISE ON GEMS. 
 
 possesses strong double reflection of light; the lustre is between 
 vitreous and resinous ; cross fracture conchoidal; the crystals are all 
 striated in length ; its colours are yellowish or brownish green, orange 
 yellow, sometimes blue and black. It scratches white glass and 
 Felspar, but is scratched by Topaz. Its streak powder is white, and 
 has a specific gravity of 3.8 to 3.4. Before the blow-pipe, fusible to 
 a brownish glass. It consists of lime, alumina, silex, with some oxide 
 of iron and manganese. 
 
 Idocrase is found in different geological positions in primitive and 
 volcanic rocks, in the cavities of the Serpentine in the Alps, in Pied¬ 
 mont, Mount Somma, Vesuvius, Etna ; also Norway, Sweden, Spain ; 
 in the United States, Worcester, Massachusetts; Salisbury, Connecti¬ 
 cut; Cumberland, Rhode Island. 
 
 The Idocrase of pure green and brown colours, and transparent, is 
 used for rings and pins, and at Naples and Turin, it is principally cut 
 for jewellery on a leaden wheel, and is polished on wood with pumice 
 stone. The forms it receives are the brilliant, table and pavilion, and 
 if perfectly pure, it is mounted a jour, and otherwise, with a suitable 
 foil. The price of the Idocrase is not very high, as it is but little 
 known among the jewellers. 
 
 The Chrysolite and green Garnet are often substituted for Idocrase: 
 but the first has a greater specific gravity and is of a more vivid colour; 
 the latter is harder and likewise of greater specific gravity. 
 
 The Italian Idocrase, which is cut at Naples, is mostly called the 
 Italian Chrysolite. 
 
 XXI. HAUYNE. 
 
 The name of this mineral was given in honour of the celebrated 
 French mineralogist, the Abbe Hauy. It occurs in crystals, in a 
 dodecahedron with brilliant faces, also in grains and massive; of con¬ 
 choidal fracture; transparent and translucent; strong vitreous lustre; 
 structure imperfectly foliated. Its colours are indigo, sky, and smalt- 
 blue, also white, green, gray, and black. It scratches white glass and 
 is scratched by quartz: white streak powder; specific gravity is 2.47. 
 Before the blow pipe it loses its colour and fuses into a porous glass, 
 and with borax into a diaphanous glass, which turns yellow on cooling; 
 forms a jelly with acids. It consists of lime, alumina, silex, prot¬ 
 oxide of iron, sulphuric acid, and soda or potash. 
 
 It is found in slacked basalt, and ejections of Mount Vesuvius, on 
 Bodenmais, on the Laach Lake, in Italy, and on the island Tiree, 
 Scotland. 
 
TREATISE ON GEMS. 
 
 119 
 
 The Haiiyne is not much known yet, but has lately been used for 
 rings, ear-rings, brooches, &c.; it is cut like the Idocrase, but the price 
 will always be high on account of its scarcity. 
 
 XXII. LAPIS LAZULI. 
 
 The name of this mineral is derived from the Persian language, 
 meaning blue colour. The ancients were well acquainted with it, 
 and have employed it for other gems. The Greeks and Romans are 
 said to have called it by the name of Sapphire, calling that with specks 
 of iron pyrites the Sapphirus regilus; Pliny called it the Cyanus. It 
 was formerly used as a strengthening medicine. 
 
 The Lapis Lazuli very seldom occurs crystallized, and its form is 
 the oblique four-sided prism ; mostly occurring compact and in grains 
 and specks, with uneven and conchoidal fracture ; it is translucent on 
 the edges ; lustre is nearly vitreous and shining; structure is foliated ; 
 its colours are, the fine azure-blue, with different shades, and often in¬ 
 terspersed with spots or veins of pyrites. It scratches glass, but is at¬ 
 tacked by quartz and by the file; its specific gravity is 2.3 : before the 
 blow-pipe and on charcoal with difficulty runs into a white glass, but 
 with borax fuses with effervescence to a limpid glass. It consists of 
 lime, magnesia, alumina, and silex, with soda, protoxide of iron and 
 sulphuric acid. 
 
 It is generally called in trade the Armenian stone. 
 
 It is found in gangues of the older formations, and on the Buchary, 
 it exists in granite rocks, and is disseminated in all sizes of veins of 
 thin capacity; and on the Baikal Lake it is found in solid pieces ; also 
 in Siberia, Thibet, China and Chili. 
 
 The Lapis Lazuli is much used for jewellery, such as rings, pins, 
 crosses, ear-rings, &c. The best pieces are generally cut out from 
 larger lumps by means of copper saws and emery, then ground with 
 emery on a lead wheel, and polished with rotten-stone on a tin wheel. 
 The rocks which yield the Lapis Lazuli, where it is contained in 
 specks, is likewise cut for ornamental purposes, such as snuff-boxes, 
 vases, candlesticks, cups, columns, cane-handles, &c., likewise for 
 architectural ornaments and stone mosaic; the manner of cutting the 
 larger specimnes is by selecting those having the specs regularly dis¬ 
 seminated on a white ground of the rock. The most important use 
 of this mineral is that of furnishing the celebrated and beautiful 
 pigment called Ultramarine blue, used by painters in oil, and said 
 never to fade. The Lapis Lazuli takes a very high polish, but be¬ 
 comes soon dull again after being used for some time. It is sometimes 
 
120 
 
 TREATISE ON GEMS. 
 
 imitated by the Lazulite or Azure-stone, the blue carbonate of copper, 
 which, however, is not near so hard, and effervesces by testing with 
 nitric acid. Those specimens having the iron pyrites enclosed are 
 difficult to polish well, on account of the unequal hardness of both 
 minerals. 
 
 The value of the Lapis Lazuli, although depending upon its purity 
 intensity of colour and size, has nevertheless much diminished when 
 compared with its former prices. 
 
 The Chinese, who for a long time have employed the Lapis Lazuli 
 in their porcelain painting, call the pure and sky-blue stone Zuisang, 
 and the dark blue, with disseminated iron pyrites, the Tchingtchang, 
 preferring the last to the former, and work the same for many orna¬ 
 ments, such as vases, snuff-boxes, buttons and cups. 
 
 In the palace which Cathrine II. built for her favourite Orlof, at 
 St. Petersburg, there are some apartments entirely lined with Lapis 
 Lazuli, which forms a most magnificent decoration. I have several 
 slabs of three inches long, and fine azure-blue colour, in my posses¬ 
 sion. 
 
 The production of Ultramarine has been known since 1502, and 
 was already employed, under the name of Azurum Ultramarinum, by 
 Camillus Leonarius. 
 
 The process of preparing the Ultramarine was known as early as 
 the fifteenth century. The colour is now mostly prepared at Rome, 
 in the following manner; those pieces which are free from pyrites 
 specs, are first calcined and pulverized ; the powder is now formed into 
 a mass with a resinous cement (pastello), and fused at a strong heat; 
 this is now amalgamated with the hands in soft water, whereby the 
 finest colouring particles are disengaged in the water, which will soon 
 be impregnated with the blue colour; a fresh portion of water may 
 now be taken, continuing with this operation until the remains are 
 colourless. The Ultramarine, after a short time, settles to the bottom 
 of the vessels, and is then carefully separated and dried. If the 
 Lapis Lazuli was of the best quality, the product will be from two to 
 three per cent. That colour which remains yet in the mass is of in¬ 
 ferior quality, and is called the Ultramarine ashes, it is of a paler and 
 more reddish colour. 
 
 Good Ultramarine has a silky touch, and its specific gravity is 2.36. 
 It does not lose its colour if exposed to heat, but is soon discoloured by 
 acids, and forms a jelly. In order to distinguish the pure Ultramarine 
 from numerous spurious and adulterating colours, such as indigo, 
 Prussia-blue, mineral-blue, &c., it is only necessary to test the article 
 
TREATISE ON GEMS. 
 
 121 
 
 in question with some acid, when after a few minutes the real ultra- 
 marine is discoloured, yielding a clear solution and a white residuum. 
 The real, ultramarine has always been at a very high price, on ac¬ 
 count of the small product obtained from the material. An ounce of 
 the purest ultramarine is sold in France for two hundred to two hun¬ 
 dred and fifty francs, which is not within the reach of ail painters. 
 
 In the year 1828 the discovery was made by Professor Gmelin, in 
 Tubingen, that sulphuret of soda was the proper material for imita¬ 
 ting this precious and valuable pigment. By his experiments he 
 succeeded in preparing this substance from silex, alumina, soda and 
 sulphur, producing a colour in every - respect to correspond with the 
 genuine colour of the Lapis Lazuli, and bearing the same relation to 
 acids as the genuine ultramarine; and which for economy has become 
 a great object to painters and coiourmen, since a whole pound of the 
 artificial ultramarine may be purchased in France for twenty francs. 
 As it bids fair to have a great consumption, being even substituted for 
 the colours of cobalt in bluing paper, thread, or any other stuff, several 
 manufacturers have already been induced to engage largely in this 
 article; and there is now a very extensive establishment in full opera¬ 
 tion by Mr. Guimet, three leagues from Lyons, who likewise claims a 
 priority of its discovery : the Royal Porcelain Manufactory at Meissen, 
 in Saxony, also prepares it. The process of preparing the artificial 
 ultramarine, as it was first described by Gmelin, is herewith given in 
 the same manner as it was published in the Annales de Chimie. 
 
 The whole process is divided into three parts: 
 
 1. The pure hydrate of silica is prepared by fusing fine pulverized 
 quartz or pure sand with four times its own weight of salt of tartar, 
 dissolving the fused mass in water and precipitating by muriatic acid; 
 also the hydrate of alumina is prepared from alum in solution, preci¬ 
 pitated by ammonia. 
 
 2. Dissolve the silex so obtained in a hot solution of caustic soda, 
 and add to seventy parts of the pure silex seventy-two parts of alumina; 
 then evaporate these substances until a moist powder remains. 
 
 3. In a covered hessian crucible a mixture of dried sal soda, one 
 part, to two parts of sulphur, is heated gradually, until it is fully fused, 
 and to the fused mass add small, quantities of the earthy precipitate, 
 taking care not to throw in fresh quantities until all the vapours have 
 ceased ; after standing for an hour in the fire, remove the crucible and 
 allow it to cool. It now contains the ultramarine, mixed with an 
 excess of sulphuret, which is to be removed by levigation, and if sul- 
 
 p 
 
122 
 
 TREATISE ON GEMS. 
 
 phuret is still in excess, it is to be expelled by moderate heat. Should 
 the colour not be uniform, levigation is the only remedy. 
 
 XXIII. KYANITE. 
 
 The name of this mineral is derived from the Greek, signifying 
 blue, on account of its blue colour. It has been known for many 
 centuries, having been cut by a German lapidary, CornelUus, under 
 James IV. by the name of Sappare, by which it is yet known among 
 the French jewellers. 
 
 It occurs in masses composed of a confused aggregation of crystals, 
 and in distinct crystals of four or eight sided prisms, much compressed, 
 with two broad shining faces. The crystals are generally closely 
 aggregated, and are crossing or standing on each other in a hemitropic 
 form, so as to present a singular and curious aspect: some of the crys¬ 
 tals are curved, others are corrugated or wrinkled, as though they had 
 been pressed endwise, or had not room to stretch themselves at full 
 length; others are pressed into triangular shapes, &c. It has a foliated 
 structure, uneven fracture; is transparent and translucent; simple re¬ 
 fraction of light; lustre vitreous and pearly ; its colours are azure-blue 
 passing into light blue or bluish white and bluish green. It scratches 
 white glass, and is attacked by Topaz or a good file; yields a white 
 streak-powder; has a specific gravity of 3.63 to 3.67. It becomes elec¬ 
 tric by rubbing, and often assumes the positive and negative electricity 
 in one and the same specimen; is infusible before the blow-pipe, but 
 with borax it fuses with difficulty to a transparent limpid glass: acids 
 have no effect. 
 
 It consists of alumina and silex, sometimes combined with oxide of 
 iron and water. 
 
 The Kyanite is found in the micaceous, talcose and argillaceous 
 slate, at St. Gothard, and on the Tyrol, in Switzerland, in Styria, 
 Corinthia, Bohemia, Spain, Siberia, and in the United States of the 
 purest azure-blue colour, and large specimens, in Litchfield, Haddam 
 and near New-Haven, (Connecticut); Chesterfield, Conway, Gran¬ 
 ville, Deerfield, and Plainfield, (Massachusetts); Grafton, Norwich, 
 and Bellows Falls, (Vermont); Oxford (New Hampshire); East Brad¬ 
 ford, East Marlborough, and Chester county (Pennsylvania.) 
 
 The Kyanite has not yet been received as a favourite among the 
 jewellers, else it would long have been cut for the various purposes of 
 ornaments, more particularly in this country, where the localities are 
 so numerous and the colour so beautiful, and when well cut it may be 
 substituted for the Sapphire. I indulge the hope, that some jewellers 
 
TREATISE ON GEMS. 
 
 123 
 
 or lapidaries may take a hint from this remark. In France and Spain 
 it has for some years past been used for rings, brooches, and other jew¬ 
 ellery. It is generally ground with emery on a lead wheel, and with 
 pumice-stone polished on a wood plate, receiving the last polish with 
 rotten-stone. The form it receives is en. cabochon or table-cut. Usually 
 the best parts of good uniform coloured specimens are picked out for 
 the cutting. 
 
 The price of this stone depends upon the hardness, colour and po¬ 
 lish : perfect specimens command a good price. Yery fine cut specimens 
 were brought from the East Indies, and sold in France as Sapphires. 
 
 XXIV. TURQ.TJOISE. 
 
 The name of this mineral is probably derived from the country 
 whence it was generally brought into market, which is Turkey. In 
 ancient times it was used as a remedy for several diseases, and was 
 also worn as an amulet against disasters. It occurs in re i nform 
 masses and in specs; has a conchoidal fracture ; is opaque ; dull and 
 waxy lustre; its colours are blue and green, from sky-blue to apple- 
 green, sometimes yellowish: scratches Apatite, but not. Quartz nor 
 white glass, and is easily attacked by the file ; has a white streak- 
 powder; its specific gravity is 2.86 to 3.0 ; is infusible before the blow¬ 
 pipe alone, loses its blue colour and becomes yellowish-brown, but 
 fuses with borax into a limpid glass. Muriatic acid has no effect upon 
 it; and it consists of alumina, phosphoric acid, water, oxide of copper 
 and protoxide of iron. 
 
 There are two kinds of Turquoise used in trade, which differ ma¬ 
 terially in their composition, and are from different localities; they are, 
 
 1. The Turquoise from the old rock, or the true Turquoise, which 
 is generally called the Oriental Turquoise, that we receive from Per¬ 
 sia, and is of sky-blue and greenish colour. 
 
 2. The Turquoise from the new rock, the Occidental or bone and 
 tooth Turquoise, which is either dark-blue, light-blue, or bluish-green; 
 the surface of this mineral is sometimes transversed by veins which 
 are lighter than the ground ; it is of organic origin, probably coloured 
 teeth of antideluvian animals; and it owes its colour, according to 
 Bouillon Lagrange, to two per cent, of phosphate of iron contained in 
 it. It is easily distinguished from the Oriental Turquoise by its struc¬ 
 ture, internally foliated and striated, which, is an indication of a bony 
 structure; it does not take so high a polish, gets discoloured in dis¬ 
 tilled water, dissolves in acids, and is totally destroyed by aquafortis. 
 Its localities are Siberia, Languedoc in France, and other places. 
 
124 
 
 TREATISE ON GEMS 
 
 The true or Oriental Turquoise is found on small gangues of bog 
 ore and silicious shiste, in boulders, &c. A mineral by the name of 
 Kalaite, as a coating to silicious sinter, of Silesia and Saxony, has 
 some years ago been discovered. The Turquoise is brought to market 
 by the merchants of Bucharia, ready cut and polished; and in Mos¬ 
 cow it is wrought over, being ground on a lead wheel with emery, and 
 polished with rotten-stone or pumice-stone on a tin-wheel; and its last 
 and best polish is received from the jewellers, by rubbing with a linen 
 rag and rouge. Since it is often transversed with fissures and cracks 
 in the interior, it requires great caution in grinding. It is mostly cut 
 in the form en cabochon, also as thick or tablestones, and is used for 
 numerous purposes in jewellery, such as rings, ear-rings, brooches, and 
 also for mounting around the most precious gems. 
 
 The price of the Turquoise has, for the last ten years, much de¬ 
 creased ; and that of an Oriental is generally four times higher than 
 the occidental; one, the size of a pea, is worth about five dollars ; a 
 good Turquoise, sky-blue and oval cut, 5 lines long and 4* lines broad 
 was sold in France for two hundred and forty one francs ; and a light 
 blue, greenish lustre, and oval cut, 5j lines long and 5 broad, was sold 
 for five hundred francs; whereas an occidental Turquoise of 4 lines 
 long, and 3J, broad, was only sold for one hundred and twenty-one 
 francs. The Turquoise is very well imitated artificially, so much so 
 as to render it difficult to discover the difference between that and the 
 real, by adding to a precipitated solution of copper and spirits of harts¬ 
 horn, finely powdered and calcined ivory-black, and leaving the pre¬ 
 cipitate to itself for about a week, at a moderate heat, and by carefully 
 drying the same, and exposing to a gentle heat. This artificial Tur¬ 
 quoise is softer than the real, and cut with a knife in shavings, where¬ 
 as the genuine yields a white powder. The real Turquoise displays 
 in the day-time a sky-blue, and at night time a light and greenish 
 colour, is not attacked by acids, and resists the fire. 
 
 In the museum of the Imperial Academy at Moscow is a Tur¬ 
 quoise of more than three inches in length and one inch in breadth. 
 
 A jeweller at Moscow is said to have had in his possession a two 
 inch long Torquoise of the form of a heart. This formerly belonged 
 to Nadir Shah, who wore the same as an amulet, for which he asked 
 five thousand rubles. 
 
 A short time ago I beheld a splendid and one of the largest Tur¬ 
 quoise at a sale, which was one inch in size, and of blue colour, and 
 which is now in the possession of M. Livingston, Esq. 
 
TREATISE ON GEMS. 
 
 125 
 
 XXV. NATROLITE. 
 
 This mineral is of late date, and receives its name on account of 
 the soda contained in it; it occurs reniform, botryoidal and massive, 
 such as mamillary, and in alternate zones around the centre ; splintry 
 fracture; translucent on the edges ; pearly lustre; colours white, 
 yellowish-white, or reddish-brown, and the colours often alternate in 
 different layers ; it scarcely scratches glass, but is scratched by 
 Felspar ; has a white streak powder ; its specific gravity is 2.16 ; 
 fuses before the blowpipe to a colourless spongy glass ; it consists of 
 soda, alumina, silex anti water, sometimes a little oxide of iron. Its 
 localities are Switzerland, Bohemia, Saxony, Scotland, and Nova 
 Scotia. The Natrolite, on account of its susceptibility of high polish, 
 has been used for rings and other ornaments in jewellery, but has 
 not yet found much application, and its value is also very inconside¬ 
 rable. 
 
 XXVI. FLUORSPAR. 
 
 This mineral was well known to the ancients, but was not particu¬ 
 larly distinguished until the sixteenth century, when it was introduced 
 as a flux. As early as 1670 the art of etching in glass by means 
 of Fluorspar was practised at Nuremberg. 
 
 Fluorspar occurs mostly in crystals of various forms, the principal 
 of which is the octahedron with its varieties, the cube and the 
 rhomboidal dedacahedron; also massive and in specks; uneven or 
 splintry fracture ; is transparent or translucent on the edges ; simple 
 refraction of light; vitreous lustre ; its colours are purple, red, green, 
 yellow, gray, blue, white, and all its various shades, from the violet to 
 the rose-red. 
 
 It scratches lime but not glass ; yields to the knife ; has a white 
 streak powder; its specific gravity is 3.14 to 3.17; becomes electric 
 by rubbing; before the blowpipe it fuses with ebullition into an 
 opaque globule, but with borax into a transparent glass; when 
 pulverized and treated with heated sulphuric acid, it emits fluoric acid 
 gas, which is employed in etching in glass; it consists of fluoric 
 acid and lime; phosphoresces when thrown on hot iron. On 
 account of its variety, and beautiful rich colours, it comes when cut, 
 in trade, under the various names of false Emerald, false Amethyst, 
 false Ruby, and false Topaz, according to the colour it represents. It 
 is mostly found in metallifrous veins, and very rarely in the newer 
 formations. Its localities are Baden, Bohemia, Saxony, St. Gothard, 
 Derbyshire, Devonshire, and the United States, of a most beautiful 
 
126 
 
 TREATISE ON GEMS. 
 
 colour and crystals ; and of a late discovery at Russy, in St. Lawrence 
 Co., State of New York, I have specimens of crystals two feet long 
 and five wide; also in Illinois, seventeen miles from Shawneetown ; 
 Blueridge, Maryland ; Smith, Co., Tennessee ; Franklin Furnace and 
 Hamburgh, New Jersey; Saratoga Springs, Alexandria, New York; 
 Middletown, Huntington, Connecticut; Thetford, Southhampton 
 Lead mines, Massachusetts, and White Mountains, New Hampshire. 
 
 Fluorspar is cut for ring stones and shirt buttons, and particularly 
 in such forms which are intended to be substituted for other gems ; 
 but in Derbyshire are large mills for grinding, cutting and polishing 
 the Fluorspar into vases, cups, obelisks, plates, candle-sticks, &c., 
 ever since 1765, and there are now more manufactories, princi¬ 
 pally at Darbey. That Fluorspar, which may be called the 
 nodular variety, and ihe colours of which run in bands or zones, and 
 known by the technical name of Derbyshire-spar or Blue John, is 
 used for the various purposes of ornaments, which are distinguished 
 over the world in parlours or mineral collections. In order to heighten 
 the various colours in the ornamental specimens before they are 
 polished, they are heated to a certain degree, when the dark spots, or 
 tints will disappear, and the coloured bands appear more distinct. 
 
 Fluorspar is often intermixed with lead ore, called Galena, and 
 which gives, when polished, a beautiful appearance. Ornaments of 
 Fluorspar still command a high price, which, however, depends a 
 good deal on the perfect qualities of the various specimens, according 
 to colour, size, &c. 
 
 A translucent variety of Fluorspar, called Chlorophane, found in 
 Cornwall, England, and Siberia, and principally in the United States, 
 in New Stratford, Connecticut, is of beautiful variegated colours, but 
 principally blue, violet and green, is mostly interesting on account of 
 its phosphorescence ; when put on hot iron in a dark room, it emits a 
 most beautiful emerald green light. A beautiful vase of Derbyshire- 
 spar may be seen in the collection of the New York Lyceum of 
 Natural History, as also crystalline groups. 
 
 XXVII. MALACHITE. 
 
 The name of this mineral is from the Greek, alluding to its colour, 
 and was well known to the ancients; and Theophrastus called it the 
 Pseudo Emerald ; it was worn also as an amulet. 
 
 It occurs tuberose, globular, reniform, mamillary and stalactiform; 
 also in fibres; has an uneven conchoidal and splintry fracture; is 
 
TREATISE ON GEMS. 
 
 127 
 
 opaque; dull and shining lustre ; has an Emerald or verdigris green 
 colour, alternating sometimes in stripes of the different shades of 
 green. It scratches lime, but not glass ; its streak powder is of 
 lighter colour than the mineral; its specific gravity is 3.67; before 
 the blowpipe it decrepitates and turns black; with borax it is reduced 
 to a metallic grain; it effervesces with nitric acid ; is dissolved, and 
 forms a blue colour with ammonia ; and it consists of oxide of copper, 
 carbonic acid and water. 
 
 The Malachite is found in various rocks, primitive as well as 
 secondary, on gangues and strata. The finest specimens are obtained 
 in Siberia, Tyrol, France, Hungary, Norway, Sweden, England, 
 Bohemia, and the United States, in a great number of localities, but 
 either in small specimens, or a coating of other copper ores, which will 
 ever render it useless for ornamental purposes. The principal locali¬ 
 ties in this country are in New Jersey, Connecticut, and all the copper 
 mines ; also in the Island of Cuba, from where I have seen some 
 good compact specimens. 
 
 Some very fine specimens of compact Malachite from Siberia, were 
 presented to the New York Lyceum of Natural History, by Charles 
 Cramer, Esq. of St. Petersburg. I also saw some excellent specimens 
 of Malachite in the collection of Dr. Martin Gay, at Boston. 
 
 The Malachite, when cut, takes a high polish, which renders it so 
 fit for the various ornaments in jewellery, as rings, pins, ear-rings, &c. 
 Likewise snuff-boxes, candlesticks, mosaics, &c. are made from it. In 
 general the specimens are assorted, and the best pieces cut on a leaden 
 wheel with emery, and polished with rotten-stone on a tin plate. Very 
 large specimens are used for table plates and large vases. 
 
 The value of the Malachite is not high, being very abundant; yet 
 much depends upon the size of the various specimens of ornament. 
 At St. Petersburg, a very large slab, said to be in the former collection 
 of Dr. Guthrie, of thirty-two inches long and seventeen inches broad, 
 and two inches thick, was valued at twenty thousand francs. Many 
 rooms in several European palaces are laid out with Malachite; and 
 the Mineralogical Museum at Jena possesses the largest collection of 
 Malachite I have ever seen, and which was presented by the Grand 
 Duchess of Saxe Weimar, a Russian princess. 
 
 An apartment in the Grand Trianon at Versailles, is furnished with 
 pier and centre tables, mantel-pieces, ewers and basins, with enormous 
 ornamental vases of Malachite, the gift of the Emperor Alexander to 
 Napoleon. 
 
12S 
 
 TREATISE ON GEMS. 
 
 XXVIII. SATIN SPAR. 
 
 This mineral occurs stalactiform, globular, reniform and massive ; 
 of fibrous texture, (that is, fine delicate fibres closely adhering together); 
 pearly lustre ; translucent on the edges : the colours are, snow-white, 
 yellowish-white, or pale-red, coloured by metallic oxides. It scratches 
 gypsum, but not glass; has a specific gravity of 2.70 ; it becomes 
 electric by rubbing; before the blow-pipe it is infusible, and changes 
 into quicklime, but borax reduces it to a clear glass. It effervesces and 
 dissolves with nitric acid; and consists of lime and carbonic acid. 
 Satin Spar is called by mineralogists the fibrous limestone, and is found 
 in the coal formations, and in the cavities of several limestones. The 
 finest specimens are found in Cumberland and Derbyshire, England ; 
 in Hungary; and in the United States, near Baltimore, in Pennsylva¬ 
 nia, also at Westfield and Newburyport, Massachusetts, where splen¬ 
 did specimens of five inches long are obtained, according to Professor 
 Hitchcock. It takes a fine polish, and is distinguished by its extra¬ 
 ordinary fine satin lustre, and is therefore used for various articles in 
 jewellery, such as ear-rings, necklaces, beads, aLo for inlaid work; 
 large specimens are used for snuff-boxes. 
 
 Satin Spar beads have been a great favourite as neck-laces and ear¬ 
 rings, and were sold a few years ago in England at very high prices. 
 In modern times, the satin beads or pearls have been imitated to a 
 great extent in France and Germany, in white and cleep-yellow co¬ 
 lours : they are made in the following manner: glass beads, of a 
 bluish-white tinge, and hollow inside, are made to imitate the reflection 
 of the Satinspar, by the scales of a small river fish called the bleak, 
 and which are suspended in dissolved isinglass; this is now dropped 
 into the bulbs, which are then turned in all directions in order to spread 
 it equally over their interior surface, and by those means the glass 
 bulbs assume the natural colour and brilliancy of the Satinspar; they 
 are harder, however, and it is easy to detect them on that account. 
 
 Fine specimens may be seen at the New York Lyceum of Natural 
 History, also in the collection of Dr. Gay, of Boston. 
 
 The Satin Gypsum, which bears the greatest resemblance to the 
 Satinspar, and only differs in its chemical constituents, (having sul¬ 
 phuric acid as a component part,) is much used for the same kind of 
 ornamental purposes, and is more abundant over the world. I have 
 seen very splendid specimens at Boston, in the beautiful collection of 
 minerals belonging to Francis Alger, Esq., who brought them from 
 Nova Scotia, and who has also given so valuable a description of all 
 the mineral treasures of that country. 
 
TREATISE ON GEMS. 
 
 129 
 
 The Satin Gypsum is, however, much softer than the Satin Spar, 
 and is much easier scratched; for -which reasons it is not so generally 
 employed. 
 
 XXIX. ALABASTER. 
 
 This mineral is a compact Gypsum, and occurs massive, with a 
 compact fracture; is translucent; has a glimmering lustre ; its colours 
 are white, reddish, or yellowish. 
 
 The purest kinds of this mineral are used in Italy for vases, cups, 
 candlesticks, and other ornaments. It is found at Castelino, in Tus¬ 
 cany, thirty-five miles from Leghorn, at two hundred feet below the 
 surface of the earth. 
 
 The yellow variety is called by the Italians Alalnst.ro Agatato, and 
 is found at Sienna; another variety of a bluish colour, is obtained at 
 Guercieto, and is remarkably beautiful, being marked with variegated 
 colours of purple, blue and red. The above Alabasters are carbonates 
 of lime. 
 
 The principal manufactory of Alabaster ornaments is at Valterra, 
 thirty-six miles from Leghorn, where about five thousand persons live 
 by this kind of labour. In making, they require great care, and to be 
 preserved from dust, as the Alabaster is difficult to clean. Talcum, 
 commonly called French chalk, will remove dirt, but the best mode of 
 restoring the colour, is to bleach the Alabaster on a grass-plat. Gum 
 water is the only cement to attach broken parts. 
 
 Plaster of Paris is likewise a compact gypsum, but contains a 
 small portion of carbonic acid, which makes it effervesce by treating 
 with acids. It was formerly only exported from Montmartre, near Paris, 
 hence its name; it is much used in ornamenting rooms in stucco, in 
 taking impressions of medals, and in casting statues, busts, vases, time¬ 
 piece stands, candelabras, obelisks, and for many other purposes. 
 
 The common Plaster of Paris is ground after being calcined ; and 
 in this condition it has the property of forming a pliable mass with 
 water, which soon hardens, and assumes the consistency of stone. 
 
 xxx. AMBER. 
 
 This gem has been known to the inhabitants of remote ages : the 
 Phenecians sailed to the Baltic, (the Glessany islands), for the sole 
 purpose of obtaining 'Amber, which they wrought into chains and 
 other ornaments, that were sold to the Greeks, who called the same 
 Electrum. In the Trojan war, as Homer reports, the women wore 
 necklaces of Amber. Its electric properties were likewise known, for 
 
 Q, 
 
130 
 
 TREATISE ON GEMS. 
 
 Thales was so much surprised at that phenomenon, that he attributed 
 it to a soul in the Amber ; and Pliny says that Amber is revived by 
 heat, the nature of electricity not being understood. It was also worn 
 as an amulet, and used for medicine. But they could not agree as to 
 its origin ; Philemon, according to Pliny, classed it as a fossil; Tacitus, 
 however, judging from the insects held in it, concluded it must be a 
 vegetable juice, whence its name in Latin, Succinum, or juice. Many 
 naturalists have, until latterly, considered Amber as a mineral; but it 
 has been satisfactorily proved by Schweigger and Brewster, from its 
 chemical characters, and polarising light, to be a gum-resin, and that 
 it is the juice of a tree, called the amber tree, now extinct. 
 
 Amber occurs in nodules or roundish masses, from grains to pieces 
 the size of a man’s head; sometimes in specks ; has a conchoidal 
 fracture ; is transparent and translucent; single refraction of light; 
 resinous lustre in a high degree: the colours are wine and wax yel¬ 
 low, greenish or yellowish white, or reddish brown; sometimes the 
 colours vary in layers. It scratches gypsum, but is attacked by car¬ 
 bonate of lime; its streak-powder is yellowish-white ; has a specific 
 gravity of 1.08 to 1.10 ; it becomes electric by rubbing. Before the 
 blow-pipe it burns with a yellowish and bluish green flame, emitting 
 at the same time a dense and agreeable smoke, and leaving a carbon¬ 
 aceous residuum ; heated oil softens and makes it pliable; it does not 
 melt as easily as other resins, requiring 517° Fahrenheit; produces in 
 dry distillation an acid which is called succinic acid; also an essen¬ 
 tial oil, known by the name of oil of amber, and in the retort remains 
 a brown mass, called the resin of amber, which is used in the arts as 
 amber varnish ; any essential oil, or spirits of turpentine may be used 
 for procuring the resin; fat oils dissolve the amber perfectly; in its 
 elementary constituents it consists of carbon, hydrogen and oxygen, 
 with some lime, alumina and silex. 
 
 Amber is found either thrown out by the sea, or in the small rivers 
 near it; sometimes in alluvial deposits of land or gravel in the vicinity 
 of the sea or in bituminous formations, such as lignite, bituminous 
 wood, or jet, where crystallized minerals are at the same time found, 
 such as iron pyrites, &c. 
 
 Its geological distribution is the green sand formation, or according 
 to De la Beche, to the stratified rocks, between the third and fourth 
 large group. It is found all over the world, but the principal localities 
 are the shores of the Baltic in Prussia, from Memel to Dantzic, where 
 it is collected by the inhabitants in various modes. One of the largest 
 specimens ever found on the Baltic was in 1811, measuring fourteen 
 
TREATISE ON GEMS. 131 
 
 inches in length by nine inches in breadth, and weighing twenty one 
 pounds. 
 
 I had in my own collection in the year 1831, a splendid wax-yellow 
 Amber, from the Baltic, which measured about sixty cubic inches, and 
 weighed nearly two pounds ; it is also found on the Danish coast, and 
 in Greenland, Sicily, Monrovia, Poland, France, and the West Indies. 
 A sailor is said to have found a remarkable specimen of eighteen inches 
 in length in a singular manner; the discoverer accidentally seated 
 himself on it, when he became so attracted to the amber, excited by 
 his natural heat, that it was with some difficulty he could detach him¬ 
 self from it. 
 
 In the United States we find Amber at Cape Sable in Maryland, in 
 a bed of lignite, in masses of four and five inches diameter, also near 
 Trenton, and at Camden, New Jersey, where a transparent specimen 
 of several inches in diameter was found; according to Professor Hitch¬ 
 cock, it is found at Martha’s Vineyard, Gay Head, and at Nantucket. 
 At the latter place, a light coloured specimen was found, of three or 
 four inches diameter, which is in the collection of P. A. Greene, Esq. 
 of New Bedford. 
 
 The production of Amber depends upon the position of the respective 
 localities; whether it is found among sand and gravel, in mines called 
 Amber mines, or in the sea, on the shore, or in smaller rivers near the 
 sea coast; and the modes of collecting are three-fold : 
 
 1. The Amber mines, which are numerous in Prussia, are wrought 
 like other mines, and explored to a depth of more than one hundred 
 feet. Shafts are constructed for raising the product from the interior 
 of the mines ; and the miners dig until they come to the amber vein, 
 which is generally found after passing a stratum of sand and a bed of 
 clay of twenty feet thickness, and another stratum of decomposing 
 trees or lignite, which may be fifty feet through ; they come then to the 
 pits, which by the characteristic colour of the soil is the best indication 
 to search for them. 
 
 2. The second mode of collecting the Amber in the sea, is effected 
 generally after a storm, by the fishermen, who either wade into the 
 water, provided with leather dresses, to their necks, or they use small 
 boats, and find at the depth of three fathoms the floating Amber. 
 
 3. It is mostly, however, collected in large quantities on the shore, 
 after having been thrown up in severe storms. 
 
 The Amber fishermen are by practice pretty well skilled in finding 
 out the proper spots where the largest quantities may be obtained. 
 
 Amber from the mines does not essentially differ from that of the 
 
132 
 
 TREATISE ON GEMS. 
 
 sea, except that the former is rather more brittle, and is often covered 
 with an earthy crust. 
 
 The Amber is assorted before it comes into the hands of the lapi¬ 
 dary or merchant, and according to size and clearness of colour, they 
 have their technical names, either, 
 
 1. The exquisite specimens, which are perfectly pure, transparent 
 and compact, weighing from five to six ounces or more, are employed 
 in larger ornaments and specimens of the arts, and fetch the highest 
 price. 
 
 2. The ton stones, which are from a quarter to four ounces, the 
 larger or purest pieces of which go for jewellery, and the impure for 
 incense or medicine. 
 
 3. The nodules are still smaller. 
 
 4. The varnish stones are yet smaller than the former, but are very 
 pure and hard so as to be easily pulverized, and are used for varnishes, 
 sealing wax, &c. 
 
 5. The sandstones are very small, opaque and perforated pieces. 
 
 6. The lumps are large but impure specimens, unfit for a lapidary’s 
 use; they are sold as specimens, or employed as incense or for the 
 manufacture of succinic acid. 
 
 7. Refuse are those pieces falling off at the lapidary’s bench. 
 
 The pure Amber receives from the lapidary distinct names accord¬ 
 ing to the shades of colour it possesses, such as egg, pale and light 
 yellow, and so into its brownish shades. The assorted Amber is then 
 treated according to the various purposes it is intended for, and receives 
 its requisite form by cleaving with an appropriate instrument or chisel, 
 by which, also the external crust is removed. It is generally believed 
 that the worse the crust is in appearance, the more beautiful is the in¬ 
 terior of the Amber. 
 
 Amber, taking a very high polish, is employed to a [great many 
 purposes of jewellery and ornaments, such as beads, necklaces, brace¬ 
 lets, ear-rings, buttons, rosaries, mouth-pieces for pipes, cane-lieads, 
 snuff-boxes, work-boxes, &c. It is generally wrought on the turner’s 
 lathe, by steel instruments, and is easily bored; it is polished on a 
 leaden wheel with pumice-stone, then with linen or a hat-body and 
 rotten-stone, and lastly by rubbing it with the hand. Common spe¬ 
 cimens are polished with a linen rag, and chalk and water. Beads of 
 amber must be drilled before receiving the facets. In cutting and 
 working amber, care must be taken not to overheat it with friction, in 
 which case it is liable to crack. Amber has occasionally been cut into 
 cameos, busts, images, &,c. 
 
TREATISE ON GEMS. 
 
 133 
 
 Impure Amber pieces may be much improved by wrapping them 
 in paper and allowing them to digest for forty hours in hot ashes, in 
 a pot filled with sand ; or by boiling them with gradually increased 
 heat in linseed oil. Amber may also be coloured red, blue and 
 violet, and dissolved in absolute alcohol; it may be cast into different 
 ornaments. Broken Amber may be mended by a cement of linseed 
 oil, gum mastic and litharge; or by moistening the ends of both 
 pieces with potash, warming the same and pressing at the same 
 time the parts together. 
 
 The price of Amber has in former times been much higher than at 
 present, but size, colour and transparency always govern the same. 
 A pure exquisite specimen of one pound is sold for forty dollars ; but 
 most good specimens are sent to Armenia, the East and Turkey, to 
 which places manufactured Amber goods to the amount of fifty to 
 sixty thousand dollars are exported from one manufactory at Stolpe, 
 in East Prussia. 
 
 Amber is often adulterated in various ways, and most particularly 
 by gum copal, which is palmed upon the ignorant for Amber, and 
 which does actually resemble it in many respects ; for both are of the 
 same colour ; both become negatively electric by friction ; both have 
 nearly the same specific gravity, and both give a pleasant odour in 
 burning; and hence when wrought as jewellery or ornaments, it is 
 not easy to distinguish the one from another. One mode of detection 
 was pointed out by the Abbe Haiiy : u If,” says he, “ a fragment of 
 Amber be attached to the point of a knife, and inflamed, it will 
 burn with some noise, and a kind of ebullition, but without liquifying 
 so as to flow: and if it should fall on any flat surface it rebounds a 
 little; whereas the copal, under similar circumstances, melts and 
 falls in drops, which become flattened.” My own experience has 
 taught me the following distinguishing characteristics: first is the 
 electro-metre, a small instrument composed of a brass needle, suspended 
 on a pin, the most essential distinguishing guide; for Amber, on 
 being rubbed, will excite the instrument about ten degrees more than 
 copal; secondly, Amber on being brought before the fire, requires a 
 pretty high temperature for melting it, and produces no kind of ebulli¬ 
 tion ; whereas copal easily liquifies, burns with much smoke, and 
 decrepidates more than Amber. 
 
 Amber is likewise adulterated by gum Arabic, gum thus, shellac, 
 and glass pastes. The latter can easily be distinguished by their 
 hardness, and the former by their solubility in hot water. 
 
 Amber very frequently has enclosed insects, such as flies, beetles, 
 
134 
 
 TREATISE ON GEMS. 
 
 &c., in a state of complete preservation. Such specimens are much 
 sought for, and command a very high price; and on that account 
 the adulterations are mostly practised, and in the following manner : 
 either by boring a hole in the Amber and introducing the beetle and 
 filling it up with pulverized gum mastic, and then let it melt over a 
 charcoal fire; or by melting the Amber, throwing in the insects and 
 letting it cool. The first adulteration may easily be detected, since 
 the mastic will never be’able to combine closely with the Amber, and 
 shows more or less cracks and fissures ; but the latter is scarcely to be 
 detected, without a scientific investigation of the enclosed insects, 
 which in the natural specimens do not exist in the present world 
 being called antediluvian, or extinct species of animals. 
 
 The most extraordinary collection of specimens of Amber may be 
 seen in the cabinet at Dantzic. A specimen of Amber of fifteen 
 pounds weight is preserved in the cabinet at Berlin. The inhabitants 
 of Colberg, in 1576, presented to the Emperor Rudolph II. a speci¬ 
 men of Amber weighing eleven pounds. 
 
 XXXI. JET. 
 
 This mineral occurs massive; has a conchoidal fracture ; is opaque; 
 shining lustre ; is of jet, velvet or pitch black colour. It is pretty soft, 
 and yields to the knife ; has a specific gravity of 1.29 to 1.35 ; it burns 
 with a greenish flame, and emits a strong bituminous smell. In trade 
 it is also called Black Amber or Pitch Coal. It is found in the brown 
 coal formation, of the plastic clay, and the lias, with lignite and amber, 
 in England, France, Silesia, Hessia, Italy, Spain and Prussia. 
 
 Jet bears a high polish, and is wrought into necklaces, ear-rings, 
 crosses, rosaries, snuff-boxes, buttons, bracelets, and particularly for 
 mourning jewellery. It is at first generally assorted to select the 
 best pieces, most suitable for working; such as are free from iron 
 pyrites, lignite, and have no cracks nor fissures. It is then turned 
 on a lathe and likewise on horizontal sand stone wheels, which run 
 unequally on their peryphery, by which the same specimens may 
 be cut and polished at the same time. During the operation the Jet 
 must be moistened with water, else it may crack from overheating. 
 It is polished with rotten-stone or crocus martis and oil, on linen, 
 or buckskin ; and lastly by the palm of the hand. 
 
 Jet was formerly a considerable branch of industry in France, 
 where, in 1786, the department de l’Aube occupied 1200 workmen ; 
 but at the present time it is no more worn, and the black enamel is 
 substituted for it. 
 
TREATISE ON GEMS. 
 
 135 
 
 XXXII. CANNEL AND ANTHRACITE COAL. 
 
 Both the above specimens of coal are employed like the Jet for 
 ornaments ; the first is manufactured in England into various orna¬ 
 ments, and the latter in the United States. At a late fair of the 
 American Institute, at New York, large candlesticks and other orna¬ 
 ments were exhibited, from a manufactory at Philadelphia, and were 
 beautiful specimens. 
 
 XXXIII. LAVA. 
 
 This mineral is a compound of several minerals, and is a volcanic 
 production. It occurs massive, with vesicular or porous marks ; of 
 splintry and conchoidal fracture; lustre dull or glistening; opaque, 
 and of gray, brown, red, yellow, black, green and white colours, with 
 all their shades. It often contains crystals of Felspar, Leucite, Horn¬ 
 blende, &c. In the arts for ornamental purposes the compact varieties 
 only are cut and polished. In Naples jewellery and ornaments in 
 great quantities are manufactured and exported ; such as pins, ear¬ 
 rings, intaglios, snuff-boxes, vases, candleabras, &c. The different 
 Lavas are cut with sand and emery, and polished with pumicestone. 
 Lava is found in all volcanic countries, and particularly at iEtna, 
 Vesuvius, Hecla, in Mexico, the Lipari Islands, &c. Lava is often 
 used as the base for Mosaic works. The blue Lava of Mount 
 Vesuvius has the appearance of artificial blue enamel, and is much 
 sought for as jewellery and other ornaments. I have inspected fine 
 specimens of polished slabs at the Boston Society of Natural History. 
 
 XXXIV. JADE. 
 
 This mineral is called in mineralogical works Nephrite, Hatchet 
 Stone, Punamu. It occurs massive; has a splintry fracture; a 
 greasy lustre when polished ; is translucent; scratches glass, and is 
 attacked by Felspar; is of mountain grass and sea-green colours; is 
 fusible into a greenish glass; it consists of silex, lime, alumnia, 
 magnesia and iron. It was originally found in China, Egypt, on 
 the Amazon River, in an Island in New Zealand, called Pavai 
 Punamu, and in the United States, (Smithfield, R. I. and Newbury, 
 Mass.) 
 
 It is used for snuff-boxes, cups, &c.; and in Turkey they use it 
 for handles to sabres, daggers and hatchets. Deities have frequently 
 been excavated from ancient ruins. Such I have seen a few years 
 ago in a collection of Indian curiosities brought from Mexico. 
 
136 
 
 TREATISE ON GEMS. 
 
 XXXV. SERPENTINE. 
 
 This mineral has its name from its colour, which resembles the 
 skin of a serpent. It is generally divided into two varieties, the 
 Common or Opaque Serpentine, and the Precious, Noble or Trans¬ 
 lucent Serpentine. 
 
 Serpentine occurs massive; the common is occasionally crystallized 
 in rhomboidal crystals, in Norway, New Jersey, Pennsylvania; has 
 a splintry, uneven and conchoidal fracture; is unctuous to the touch ; 
 yields to the knife; colours are green in all its shades, but also 
 reddish and grayish; has a specific gravity of 2.5 ; infusible before 
 the blowpipe, but with borax dissolves into a transparent glass. It 
 does not belong to the stratified rocks, but to the ophiolithes of 
 Broginart, and is mostly associated with granite, gneiss, micaceous, 
 chlorite, argillaceous shistes and limestone ; and therefore belongs to 
 the primitive formation. 
 
 Serpentine, for richness and variety of colours, exceeds all rocks of 
 the world ; and it abounds all over the globe, in large consolidated 
 rocks. Its localities are too numerous to be specified. In the Alps 
 we find the Serpentine nine thousand feet high; in France the 
 mountains of Limousin ; in Spain, Norway, Sweden, Scotland, Shet¬ 
 land Isles, Cornwall, Italy, Bohemia, Saxony, Bavaria, Switzerland, 
 and in the United States we find it all along the Alantic coast, where 
 the primary rocks are found, as at Hoboken, New Jersey, opposite 
 to New York City, Warwick, New Jersey; as far as] Maryland, at 
 Bare Hills, through Pennsylvania, Rhode Island, Connecticut, Massa¬ 
 chusetts, Vermont, &c. The Serpentine beds of Massachusetts are 
 inexhaustible. In Middlefield, Massachusetts, the bed is one quarter 
 mile in breadth and six miles long, which alone would be sufficient to 
 supply the whole world with a valuable material for ornamental and 
 architectural purposes. There are other beds at Westfield, Blanford, 
 Pelham, Zoar, Windsor, Marlborough, Cavendish and other towns in 
 Vermont. Another most beautiful specimen is in Newbury, near 
 Newburyport; and latterly a new locality was discovered by Dr. 
 Jackson in Lynnfield, Mass. 
 
 Serpentine encloses the chromate of iron in the Shetland Islands, 
 Maryland, &c. ; and is on that account of the highest importance to 
 the artist. 
 
 It is easily wrought on lathes into various articles; such as snuff¬ 
 boxes, vases, inkstands, &c. In a small place at Zoblitz, in Saxony, 
 several hundred persons are constantly employed in the manufacture 
 of the various utensils; such as boxes, trinkits, and chimney pieces. 
 
TREATISE ON GEMS. 
 
 137 
 
 The locality of Grenada, in Spain, has supplied many churches and 
 palaces of Madrid with large columns, and other ornaments. It is 
 really surprising that the inhabitants of those districts where the Pre¬ 
 cious Serpentine is found, have not yet started it as an article of trade, 
 as the quality of the American Serpentine is, if not superior to the 
 English and Spanish, certainly not inferior to any hitherto found: 
 and I trust that the day is not far distant when our parlours will be 
 embellished with mantel-pieces, tables, and mantel ornaments. Also, 
 candlesticks, mugs, pitchers, knife handles, firearm stands, jamb hooks 
 and many other domestic articles, may be introduced, instead of silver- 
 plated, steel, and cast iron ware. 
 
 Serpentine is often associated with a number of other minerals, 
 thus: a, Serpentine with Talc; b, Serpentine with Diallage or 
 Schiller-spar; c, Serpentine with Amianthus; d, Serpentine with 
 Asbestos ; e, Serpentine with Garnets ; f, Serpentine with Actinolite, 
 &c. That variety which contains the Amianthus in one layer, is 
 sometimes exceedingly beautiful; and when polished has the appear¬ 
 ance of Satin-spar. 
 
 XXXVI. MARBLE. 
 
 This mineral bears the name of a very extensive family; and 
 although in the form of limestone used as a building material, would 
 not deserve a place in these pages, but that a number of species or 
 varieties of Marble are, for their beauty, structure and rarity, used in 
 jewellery as ornaments. I will, therefore, out of the large class of 
 Marble, limestone, or calcareous Spar, enumerate those varieties 
 which are within the reach of our object. 
 
 1. STALACTITE AND STALAGMITE. 
 
 It occurs in large tuberous, undulated masses ; botryoidal, mammil¬ 
 lary or concretional, either in icicles or circles; of fibrous fracture; 
 translucent; pearly lustre; colour generally yellowish-white and 
 white; its composition is calcareous spar; it originates in caverns, 
 through which the water filters, and on its ultimate evaporation 
 leaves this carbonate of lime in various forms, which sometimes 
 imitate altars, pillars, animals, &c. 
 
 Those pillars or icicles which are pendant from the roof, and those 
 rising from the base, are sometimes divided into Stalactite for the 
 first, and Stalagmite for the latter. But the cause of their existence 
 is the same, and there ought not to be any distinction in their 
 nomenclature. 
 
 R 
 
138 
 
 TREATISE ON GEMS. 
 
 Ornaments of stalactite in the shape of vases, &c. are often seen 
 in fancy stores. The greatest localities of this mineral are, the Grotto 
 of Antiparos, Bauman’s Cave in the Hartz, which I visited in 1827, 
 and which displays gigantic stalactites ; also Derbyshire, and in the 
 United States, are very celebrated caves, which yield this article. 
 
 They have lately been described by my friend Charles Cramer, Esq. 
 Russian Vice Consul at New York, an enthusiastic and useful mine¬ 
 ralogist of St. Petersburg, in a pamphlet published by the Imperial 
 Mineralogical Society of St. Petersburg, in the German language; and 
 as this interesting little work is not accessible to all, I will here translate 
 the index of all the caves enumerated by him as North American. 
 Canada —Grotto in the Niagara, 
 
 A cave in Lanark, Upper Canada, 
 
 A smaller cave at the same place. 
 
 New-Hampshire —The Devil’s Cave. 
 
 Vermont —The caves in Bennington, 
 
 ” ” Dorset. 
 
 Massachusetts —The Natural bridge and cave at Nahant, 
 
 ” over the Hudson brook, 
 
 The cave near Sunderland, 
 
 ” in Berkshire, 
 
 Two caves in New Marlborough, 
 
 The cave near West Stockbridge, 
 
 ” in Lanesboro’ 
 
 ” in Adams, 
 
 The Purgatories, near Sutton. 
 
 Connecticut —The West Rock cave. New Haven, 
 
 Rhode Island —The Purgatory, near Newport 
 The Spouting, near ditto. 
 
 New York —Cave near Watertown, 
 
 ” at the Niagara, 
 
 Ball’s Cave, 
 
 Knox Cave, 
 
 The Monito at Wigwam or Devil’s Abode, 
 
 Esopus Cave. 
 
 Pennsylvania —The Devil’s Hole, in Bucks county, 
 
 The cave on the Swatera river. 
 
 Maryland —Hughes Cave, 
 
 The cave at Harwell. 
 
 Virginia —Weyer’s Cave, 
 
 Wreast’s Cave, 
 
TREATISE ON GEMS. 
 
 139 
 
 Madison’s Cave, 
 
 Zane’s Cave, 
 
 Blowing Cave, near the Panther Dale, 
 
 Greenbriar’s Cave, 
 
 Cave on the Kanhawa River, 
 
 Chapin’s Cave, 
 
 Johnson’s Cave, 
 
 Allen’s Cave, 
 
 Ruffner’s Cave, 
 
 Roger’s Cave, 
 
 Reid’s Cave, 
 
 Natural Tunnel in Scott County, 
 
 Natural Bridge in Rockbridge County. 
 
 Ohio —Mason’s Cave, 
 
 Nature’s Building, or Cave in the Rock. 
 
 Indiana —Epsom Salt Cave, 
 
 Cave near Corydon. 
 
 Kentucky —Boone’s Cave, 
 
 Russel’s Cave, 
 
 White Cave, 
 
 Mammoth’s Cave, 
 
 Cave on the Crooked Creek. 
 
 Tennesee— Big-bone Cave, 
 
 Arched Cave. 
 
 South Carolina —Great Flat Rock Cave, 
 
 Lover’s Leap. 
 
 Georgia-— Nicojack Cave. 
 
 Missouri —Ashley’s Cave. 
 
 Mississippi —The Abode of the Great Spirit on the North West Coast, 
 Cave on the Copper River. 
 
 Mexico —The Dantoe Cave, 
 
 Chamacasapa Cave, 
 
 San Fillipe Cave. 
 
 Cuba —The Cave near Matanzas. 
 
 Hayti —The Cave near St. Domingo. 
 
 Peru —The Cave in the Andes. 
 
 New Andalusia— The Canipe Cave. 
 
 Mr. Cramer mentions the size of the stalagmites in the anti-cham¬ 
 ber of Weyer’s Cave, being twelve feet high; those in Solomon’s 
 
 Temple of the same, twenty-five feet high, which are nearly transpa¬ 
 rent ; and its Hermit Chandelier, four feet high, and twelve feet in 
 
140 
 
 TREATISE ON GEMS. 
 
 circumference ; the colossal stalagmite in Washington Hall, which is 
 said to represent the father of his country wrapped in his cloak; and 
 the Pompey’s column of thirty feet high ; also the Babylon’s Tower, 
 of thirty feet circumference. 
 
 2. EGYPTIAN MARBLE, 
 
 Which is generally milk-white or grayish-white and bluish, and also 
 black and red, which is called the Rosso Antico; it is of a close gran¬ 
 ular structure, and was a great favourite with the ancient architects. 
 
 3. ITALIAN MARBLES. 
 
 With these may be counted the Parian marble; the Pentelian mar¬ 
 ble; theVenitian or Lombardy marble, which is quite translucent; the 
 Luni and Carara marble; and the Laconian marble, or Yerde Antico. 
 They have all yielded the materials for the most ancient Greek and 
 Italian sculptors. The Venus de Medici, the Diana hunting, and 
 Venus leaving the bath, are of the Parian marble : a Bacchus in re¬ 
 pose, a Jason, a Paris, and many Grecian monuments, are from the 
 Pentelian marble, which comes from the vicinity of Athens. 
 
 4. AMERICAN MARBLES. 
 
 The varieties of marble, which is inexhaustible in the United States, 
 are very numerous ; and I am proud to assert, that for architectural 
 and ornamental purposes, they may fully compete with any foreign 
 country. The colours are variegated from (he snow-white to the black 
 with gold and grass-green veins. A small district in New England, 
 of about fifty miles in extent, concentrates, I may say, the marbles 
 which may be collected in Europe through a space of two thousand 
 square miles ; for we find in the county of Berkshire, and that of New 
 Haven, the representatives of marbles from Italy and Ireland; and 
 the discoveries which are constantly made of additional marble local¬ 
 ities are a source of great rejoicing. Thirty years ago, the City Hall 
 of New York city was built of marble from WestStockbridge, Massa¬ 
 chusetts, which was transported at great expense, a distance of over 
 four hundred miles ; whereas, afterwards, the same quality of marble 
 was discovered on New York island, but a few miles distant. Ac¬ 
 cording to professor Dewey, the county of Berkshire alone turned out 
 forty thousand dollars worth of marble several years ago. I will here 
 enumerate a few of the most interesting marble quarries, such as 
 
 a, The Philadelphia marble, which is snow or grayish white, and 
 sometimes variegated with blue veins, which takes a very high polish. 
 
 b, The Potomac marble, which is properly called a Breccia, being 
 
TREATISE ON GEMS. 
 
 141 
 
 composed of rounded and angular fragments from the size of a pea 
 to that of an ostrich’s egg. Its colours are red, white, gray and 
 blackish brown, intermixed ; which takes a very fine polish, and forms 
 a most beautiful ornamental stone. It comes from the banks of the 
 Potomac, in Maryland. Specimens of this may be seen in the columns 
 of the Chamber of Representatives at Washington, twenty feet high, 
 and two feet diameter. 
 
 c, The Verde Antico, of New Haven, Connecticut. This marble is 
 intermixed with serpentine veins, and has a most beautiful appearance. 
 There are inexhaustible quarries of it at New Haven and Milford, 
 which bid fair to rival any other ornamental stone in the world. 
 Four chimney-pieces of this mineral were purchased for the Capitol at 
 Washington ; and I lately examined a splendid centre table, wholly 
 cut from this marble, that was exhibited at the tenth annual fair of the 
 American Institute. It is to be hoped that some company may under¬ 
 take to introduce this marble more extensively into our houses; for it 
 appears not yet sufficiently known among the wealthy citizens, and 
 the enterprise will repay every effort. Large slabs may be seen at the 
 New York Lyceum of Natural History, at the cabinet of Yale College, 
 New Haven, and I possess a very fine large slab, polished. Ports¬ 
 mouth, Vt. likewise possesses splendid Verde Antico, specimens of 
 which may be seen at the American Institute in New York. 
 
 d, Berkshire county in Massachusetts, may justly be called the 
 marble pillar of the United States; and, as professor Hitchcock re¬ 
 marks, that the inhabitants of that county cannot but regard their 
 inexhaustible deposits of marble as a rich treasure to themselves, and 
 an invaluable legacy to their posterity. The towns, West Stockbridge, 
 Lanesborough, New Ashford, Sheffield, New Marlborough and Adams 
 of that county, keep thousands of hands constantly working in their 
 quarries. In 1827, two thousand seven hundred tons of marble were 
 exported from that town ; and in 1828, a block of from fifty to sixty 
 square feet, and eight thick, was raised by one charge of gunpowder. 
 
 e, White, fine, granular marble, bearing the greatest resemblance 
 to the celebrated Carara marble, is obtained from Smithfield, R. I. and 
 Stoneham. Massachusetts. 
 
 5. SHELL MARBLE. 
 
 This mineral is a secondary marble, and is called also conchitic 
 marble, on account of its containing petrified shells, which, when po¬ 
 lished, communicate to their matrix the marble, a most beautifully 
 variegated appearance. 
 
142 
 
 TREATISE ON GEMS. 
 
 a, The Lumachelle marble is a kind which is very scarce ; it has 
 a gray or brown ground, interspersed with shells of a circular form and 
 golden colour, and when held towards the reflection of light, displays 
 red, blue and green tints, like those of the precious opal or iridescent 
 Labrador. 
 
 It is sometimes seen in the form of pins and other jewellery ; but 
 stands, on account of its scarcity, very high in price; the only locality 
 is in Corinthia; one in Devonshire, England, being exhausted. Some 
 splendid specimens from Corinthia, are in the collection of the Baron 
 de Lederer, Austrian consul of this city ; and a very fine specimen of 
 the Lumachelle, at the Boston Society of Natural History, was marked 
 with the locality of Neufchatel. 
 
 b , The Panno di Morto, or funeral pall, is a deep black marble, with 
 white shells, like snails, which is only seen at Rome, and very scarce. 
 
 c, The Bristol marble, from England, is a black marble, interspersed 
 with white shells. 
 
 d , The Italian shell marbles from Florence, Lucca, and Pisa, are 
 red, containing white shells (ammonites). 
 
 e, The French shell marbles are very numerous; those from Nar- 
 bonne are black with white belemnites; that from Caen is a brown 
 marble, with madreporites ; and those from Languedoc are of a fiery 
 red colour, mixed with white and gray univalve shells ; of this Napo¬ 
 leon’s eight columns for his triumphal arch in the Carousel at Paris 
 are cut. 
 
 /, The United States have a good many shell marble quarries ; but 
 they are all black and gray. Those of Trenton falls and Littlefalls, 
 near Seneca lake, Northumberland co. Pennsylvania, Bernardston, 
 Mass., and Hudson, N.Y., contain either trilobites or enchrinites; some 
 take a very high polish. 
 
 6. PISOLITE AND OOLITE. 
 
 These minerals are likewise composed of carbonate of lime ; occur 
 massive, and of distinct concretional layers, either in the form of peas 
 or other round grains or pebbles, and are of a white, yellowish-white, 
 brownish or reddish colour; when cut and polished, they present fine 
 ornamental stone, and make a very effective appearance. The first 
 is found in alluvial deposits of the hot water mineral springs of Carls¬ 
 bad in Bohemia, and the baths of St. Philip in Tuscany ; the latter 
 forms large beds in England and France. The city of Bath, in Eng¬ 
 land, is mostly built of this limestone. 
 
TREATISE ON GEMS. 
 
 143 
 
 7. THE ROCK OF GIBRALTER. 
 
 This is likewise a carbonate of lime, occurs massive, mostly striped; 
 is yellowish-white, yellow and brownish; is only found in that rock 
 from whence it takes its name, and has formerly been a great favourite 
 in jewellery and other ornaments. At this day we see in shops and 
 private houses pins, broaches, ear-rings, seals, cane-handles, snuff-boxes, 
 letter-holders, vases, urns, candelabras, obelisks, &c. It takes a high 
 polish. 
 
 XXXVII. APATITE. 
 
 This mineral has its name from its colour, meaning deceptive, and 
 resembling the colour of some more precious gems ; it occurs in six- 
 sided prisms, of conchoidal fracture, vitreous lustre, is translucent, and 
 yields to the knife; its colours are white, yellowish-white, greenish- 
 yellow, blue, bluish-green, grass-green and reddish. It resembles the 
 beryl and emerald, but is distinguishable in colour and hardness; is 
 found in primitive rocks ; its localities are extended all over the world, 
 more abundantly in the United States. Specimens of three or four 
 inch crystals from Etonville, N. Y., have a splendid appearance, and 
 if cut and polished, would make fine pins, ear-rings, and other orna¬ 
 ments and jewellery. 
 
 XXXVIII. LEPIDOLITE. 
 
 This mineral derives its name from the Greek language, from its 
 scaly structure; it occurs massive, presenting an aggregate of minute 
 shining, flexible scales or hexagonal plates; splintry fracture; glistening 
 and pearly lustre; translucent on the edges ; its colours are, lilac and 
 rose red, and pearl gray, greenish yellow and blue; is scratched by 
 glass, and yields to the knife; has a specific gravity of 2.81; is fusible 
 with ease into a transparent globule. It is found in the granite and 
 primitive lime, in Monrovia, France, Island of Elba, Corsica, Sweden, 
 and in the United States, in Maine, New Hampshire, Vermont and 
 Massachusetts. It is cut in Europe for various ornaments, such as 
 plates, vases, snuff-boxes, &c., and will, I trust, at some future day, be 
 more extensively used in jewellery; for there are some variegated 
 specimens of the peach-blossom colour, and very fine granular struc¬ 
 ture, which are extremely beautiful. 
 
 XXXIX. MICA. 
 
 This mineral occurs crystallized, in six-sided tables and oblique 
 rhombic prisms, and massive; also disseminated ; has a perfectly foli- 
 
144 
 
 TREATISE ON GEMS. 
 
 ated structure, glittering and metallic iustre; is transparent and trans¬ 
 lucent, very fusible and elastic : its colours are, white, green, black, 
 brown, peach-red, yellowish and bluish; has a specific gravity of 2.7. 
 It is found in primitive rocks, and forms an ingredient in granite 
 gneiss, mica slate, and other rocks, where it more or less predominates; 
 its localities are, therefore, universal, but in Siberia it forms large beds 
 and is quarried for special purposes, as a substitute for glass windows; 
 and although the United States afford ample localities for the same, 
 yet a few years ago quantities were imported here for the doors of 
 Nott’s stoves. 
 
 The Plumose Mica is beautiful variety, and derives its name from 
 its resemblance to a quill or plume, the lamellar or fine delicate crys¬ 
 tals diverging in such a manner. It is of pearl-gray colour, and is 
 found in the United States ; in Williamsbury, Mass., Hartford, Con., 
 and many other places. The green Mica is of a beautiful grass- 
 green colour, and is found in Brunswick, Me. The rose-red Mica is 
 a very beautiful mineral, and is found in numerous places, in this 
 country ; principally in Goshen, Chesterfield, Mass.; Acworth, N. 
 H.; Bellows Falls, Yt., &c. The Mica may, when of good colours, 
 be used for jewellery and other ornaments, as well as the Lepidolite. 
 
 XL. PYRITES. 
 
 This mineral is called Sulphuret of Iron, Iron Pyrites and Marka- 
 site. It occurs crystallized in many forms; such as the cube, octa¬ 
 hedron, dodecahedron, massive, disseminated, capillary and cellular ; 
 has a conchoidal fracture ; brilliant metallic lustre ; its colours are 
 bronze, yellow, brass-yellow and steel-gray. This mineral takes a 
 very high polish, and from its brilliant lustre looks extremely well 
 when cut in the form of a brilliant or rose. It was formerly much 
 used in jewellery for ear-rings, rings, pins, and necklaces. It was 
 in former times, considered a great preservative of health. It is now 
 but seldom seen, except in collections of mineralogical cabinets. 
 
 XLI. ROSE MANGANESE. 
 
 This mineral is called in mineralogical works the Siliceous Oxide 
 of Manganese, and also the Carbonate of Manganese. It occurs 
 massive; foliated structure; conchoidal fracture; shining lustre; 
 scratches glass; its colours are the rose-red, reddish and yellowish. 
 
 It is found in Siberia, Sweden, Hungary, England ; and in the 
 United States, at Middlebury, Yt., and at Cummington and Plain- 
 field, Mass., where, according to professor Hitchcock, the siliceous 
 
TREATISE ON GEMS. 
 
 145 
 
 oxide, or according to Dr. Thompson, the bisilicate of Manganese is 
 found in great abundance. Since it takes a very high polish, and is 
 much wrought at Oatharineburg in Siberia, into many ornaments, it 
 is confidently to be hoped that it may also find its amateurs in this 
 country, as it is very easy to cut and polish, and the material so 
 plenty. 
 
 XLII. PORPHYRY. 
 
 This mineral forms rocks in a geological sense, but is properly a 
 compact Felspar. It has various colours and shades, with imbedded 
 crystals of Felspar and Quartz, or either of them, and is as may be 
 supposed a very hard stone. It is much used in Europe for orna¬ 
 mental and architectural purposes ; also for slabs, mortars and other 
 economical uses. 
 
 In the United States, Porphyry has never been used for any 
 purpose; and professor Hitchcock remarks, in his Geological Report 
 of the State of Massachusetts, that it would be strange if an increase 
 of wealth and refinement should not create some demand for so 
 elegant and enduring a rock as Porphyry. In the same excellent 
 work the author classifies Porphyry in four varieties as occurring in 
 Massachusetts, in the neighbourhood of Boston : 
 
 1st. Compact Felspar, with several predominating colours ; the one 
 with yellow, resembling the Turkey Stone; one with red, from 
 brownish to blood-red, closely resembling Jasper; one with rose-red 
 colour, resembling the Rose Petrosilex of Europe. 
 
 2d. Antique Porphyry; closely resembling that European Porphyry 
 which was employed by the ancients in monuments and ornamental 
 furniture and forms, and when polished a beautiful ornament. It 
 presents numerous varieties and shades of colour : one of the most 
 elegant is the fight green ; then a deep green; red of various shades ; 
 reddish-brown ; black, or nearly so ; gray and purple ; and the imbed¬ 
 ded crystals are usually of a fight colour, sometimes white, brown, 
 and greenish. 
 
 3d. Porphyry with two or more minerals imbedded, and its base 
 of common Felspar. This mineral is between Sienite and Porphyry, 
 resembling the Trachytic Porphyry, and is generally unfit for orna¬ 
 mental purposes; the Quartz which it contains is hyaline and smoky. 
 
 4th. The Brecciated Porphyry, which is composed of angular 
 framgents of Porphyry and compact Felspar, reunited by a paste of 
 the same material; the fragments are also of various colours, usually 
 
 s 
 
146 
 
 TREATISE ON GEMS. 
 
 however, gray and red ; the rock is very hard, and when polished 
 presents specimens of great delicacy for ornamental purposes. 
 
 XLIII. SIENITE. 
 
 This rock is composed of Felspar and Hornblende with Quartz 
 and Mica, with either of them, or without either of the two latter 
 ingredients. When polished it forms the most splendid ornamental 
 stone of all the other rocks ; it is very l^ard ; and its colour and dis¬ 
 tribution of the various ingredients are very agreeable to the eye. It 
 much resembles Granite, and mostly identical: by closer inspection 
 it may be yet distinguished from the want or addition of the compo¬ 
 nent ingredients. 
 
 Professor Hitchcock describes six varieties of the Sienite : 
 
 1st. that Sienite which is composed of Felspar and Hornblende, 
 when the first is white, greenish, and yellowish, and the latter invari¬ 
 ably black. 
 
 2d. Felspar, Quartz and Hornblende; the first is foliated, and 
 commonly of a grayish, bluish or yellowish colour; the second from 
 quite light to quite dark colour and hyaline ; and the latter is black. 
 To this variety the quarries at Quincy and Cape Ann have been 
 arranged by the author, which are generally called Granite, on 
 account of the absence of Mica. The Quincy Granite, or rather 
 Sienite, is that celebrated architectural material used in the cities of 
 Boston and New York, for those huge and magnificent, edifices, 
 public as well as private, erected within the last six years; and it 
 may be supposed that two thousand buildings of the city of New 
 York have been furnished with this splendid article. 
 
 3d. Felspar, Hornblende, Quartz and Mica. This rock, likewise, 
 has a beautiful appearance, but is, as yet, less wrought than the 
 other varieties. The Felspar and Hornblende are predominating. 
 The Quartz is in small grains and the Mica is black. 
 
 4th. The Porphyritic Sienite; its base is Quartz and Felspar, and 
 the Hornblende is almost entirely absent; it has a porphyritic aspect; 
 the Felspar predominating. It is the most ornamental stone when 
 polished. 
 
 5th. Conglomerated Sienite ; it is a quaternary compound of Fel¬ 
 spar, Hornblende, Quartz and Mica, but all in rounded or conglome¬ 
 rated masses, having the aspect of a pudding stone ; the nodules are 
 from half an inch to six inches in size, and may be easily broken out 
 of the mass, and the Hornblende predominates mostly in them. It 
 is unfit for architectural purposes. 
 
TREATISE ON GEMS. 
 
 147 
 
 6th. The Augitic Sienite ; in this rock the Hornblende is present 
 and Mica absent. It is composed of black Hornblende, greenish 
 Agate, and yellowish Felspar; all, except the Felspar, presenting a 
 crystalline structure, or also composed only of Agate and Felspar. 
 
 The name of the rock Sienite is originally derived from Sienna, in 
 Upper Egypt, from whence the first specimen was identified by 
 Warner; and many of the Egyptian monuments, such as Cleopatra’s 
 Needle, and Pompey’s Pillar, were obtained from there. 
 
 XLIV. GRANITE. 
 
 This rock is composed of Quartz, Felspar and Mica, and forms 
 the crust of our globe. It abounds over the whole earth, and the 
 eastern part of the United States is particularly favoured with this 
 valuable mineral. As a building material it has been most exten¬ 
 sively used for the last ten years; but the great fire, which con¬ 
 sumed, in December, 1835, seven hundred buildings, among which 
 about two hundred were erected of Granite, has given a sufficient 
 proof that Granite is in this changeable climate unfit for building 
 material, but may be usefully employed for ornamental and architec¬ 
 tural purposes, where it is not in constant exposure to the atmosphere 
 and weather, which make it so liable to decomposition. 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ' 
 
 
 
 
 
 
 
 
 
 . 
 
 
 
APPENDIX. 
 
 PEARLS. 
 
 The Pearls are concretions consisting of carbonate of lime, of a 
 roundish, tubercular, or angular form, of a white, gray, blue or green 
 colour, shining lustre, and of the hardness of lime. They are found 
 in several bivalve shells, particularly however in the Mother of Pearl, 
 (ovicula marga vitifera); also in the oyster, and several unios. The 
 origin of the Pearl is by some considered to be unfructified eggs ; by 
 others, a morbid concretion or calculus, produced by the endeavour of 
 the animal in the shell to fill up holes therein ; by others again, as 
 mere concretions of the juice of which the shell has been formed, and 
 with which the animal annually augments it. It is very plausible, 
 however, that the animal of the shell is attacked often by enemies, 
 such as the boring shells, turritella, &c.; that grains of sand, or any 
 other pointed substance, which, on such occasions, come within the 
 shell, stick fast and augment with the growth of the shell; it is also 
 known that the Pearls may be produced artificially, by pressing a 
 sharp body on, or by boring a hole in, the shell. The Chinese are in 
 the habit of laying a string with five or six small pearls separated by 
 knots, inside of the shell, when they are exposing themselves to the 
 sun, and take them out after some years, whereby they obtain very 
 fine and large pearls, and but a little open on the side where they 
 were adhering to the shell. The pearl fishers say that when the shell 
 is smooth and perfect, they never expect to find any Pearls, but always 
 do so, when it has begun to be deformed and distorted. It is therefore 
 concluded, that as the fish grew old, the vessels containing the juice 
 for forming the shell and keeping it in vigour, became weak and rup¬ 
 tured, and from this juice accumulating in the fish, the Pearl was 
 formed and the shell brought to decay, as supposed by Mr. Reaumur. 
 It would be, according to this idea, a sure guide to know from the 
 form of the shell, whether the Pearl is large or small; and thus by the 
 
150 
 
 APPENDIX. 
 
 smaller ones being thrown back into the sea, a constant crop of large 
 Pearls might be obtained. The mother of pearl fish is found in the 
 East and West Indies, and other seas in warm latitudes, and in rivers 
 of north and middle Europe. In some parts of the globe, they are 
 found in clusters of a great number, which places are called pearl 
 banks. The most famous are near the coast of Ceylon, that of Japan, 
 and in the Persian Gulf, near the island of Bahreim ; also near the 
 coast of Java, Sumatra, &c. The finest and most costly pearls are 
 called the Oriental, and are from the above places: they are all white 
 or yellowish ; those from the Persian Gulf, on account of their perfect 
 whiteness, are preferred to those from Ceylon. Pearls are collected in 
 rivers with the hand, but in seas it is the business of divers, brought 
 up to this most dangerous occupation from early youth. In the East 
 Indies there are two seasons for pearl fishing, the first in March and 
 April, the second in August and September ; and the more rain, the 
 more plentiful are the pearl fisheries. In the beginning of the season 
 there are sometimes two hundred and fifty barks on the banks ; the 
 larger barks have two divers, the smaller one. The divers descend 
 from their barks with a rope round their body, and a stone of twenty 
 or thirty pounds attached to one of their feet, so that they may sink 
 speedily from eight to twelve fathoms, where they meet the shells fas¬ 
 tened to the rocks : their nostrils and ears are stuffed up with cotton, 
 to the arm a sponge dipped in oil is fastened, which the diver now and 
 then brings to his mouth, in order to draw breath without swallowing 
 water. He also carries down with him a large net, tied to his neck 
 by a long cord, the other end of which is fastened to the side of the 
 vessel, to hold the shells, and the cord is to draw him up when the net 
 is full, or when he wants air ; likewise a knife or an iron rake for de¬ 
 taching the shells from the rocks. So he precipitates himself to the 
 desired depth, where he can very distinctly see all that is passing around, 
 yet cannot escape in time the sudden approach of sharks, to whom 
 they too often become a prey. When the diver has been in the water 
 some minutes, and has his net filled, or is unable to stay any longer, 
 he loosens quickly the stone at his foot, and shakes the line, when he 
 is drawn up by his companions. The diving-bell is now frequently 
 used, more so than in former years. 
 
 In the Persian Gulf the divers rub their bodies with oil, and fasten 
 a stone of about fifty pounds to their feet. 
 
 The shells thus obtained are piled up in heaps, and left exposed to 
 the rain and sun until the body of the animal putrifies, and they open 
 of themselves. Those containing any Pearls have from eight to twelve. 
 
APPENDIX. 151 
 
 After being picked out, washed and dried, they are passed through 
 nine sieves of different sizes. 
 
 At the Pearl Islands near the Isthmus of Panama and Colombia, 
 the pearl fisheries have within a few years past become lucrative to 
 some of the inhabitants. The divers use more simple methods for 
 collecting the pearl oysters: they traverse the bay in canoes that hold 
 eight men, all of whom dive naked into the water from eight to ten 
 fathoms deep, where they remain about two minutes, during which 
 time they collect all they can with their hands, and dexterously rise to 
 deposit them in their canoe, repeating the operation for several hours. 
 
 In Sweden they catch the pearl oyster with a pair of long tongs. 
 The fishermen are in small boats, painted white on the bottom, which 
 reflects to a great depth, and take hold of them as soon as they per¬ 
 ceive them passing underneath. 
 
 Pearls are esteemed according to their size, form, colour and lustre ; 
 the largest, of the size of a small walnut, are called paragons, which 
 are very rare ; those the size of a cherry, are found more frequently, 
 but still are rare ; they are the diadem or head pearls. They receive 
 names also according to their form, whether quite round, semi-circular 
 and drum-form, or that of an ear-drop, pear-formed, onion-formed, or 
 otherwise irregularly shaped. The small pearls are called ounce pearls, 
 on account of being sold by weight, and the very smallest seed pearls. 
 Those of a brilliant white colour, or white water, are most sought for 
 in Europe ; those of a yellowish colour in some parts of Asia ; and 
 some of a lead colour, or those of a jet black are preferred among some 
 nations. They all turn more or less yellow with age, and to restore 
 the white colour they are ^either baked in bread, rubbed with boiled 
 salted rice, or kept for a short time in the gastric juice of fresh killed 
 chickens. 
 
 Pearls are sold by weight, the Troy or gold weight; but the dwt. 
 of twenty four grains is counted as thirty, so that an ounce has six 
 hundred grains pearl weight, and four Troy grains are equal to five 
 Pearl grains. The price has, within the last forty years, much dimin¬ 
 ished, for two reasons: * 
 
 1st. Diamonds, and particularly brilliants, became more plenty, and 
 have since been worn, not by the higher classes alone, but also by the 
 middling. 
 
 2d. Within the last twenty years, artificial pearls have been man¬ 
 ufactured in high perfection, and are worn to a great extent. 
 
 It is my opinion, however, that the price of Pearls will take a fresh 
 rise among the nobility and richer classes, the Diamond being now so 
 
152 
 
 appendix. 
 
 generally worn; as persons thinking to invest safely without any future 
 loss, their surplus capital, purchase brilliants that formerly were pos¬ 
 sessed exclusively by the rich. 
 
 Pearl fisheries were first carried on in remote times in the Persian 
 Gulf, and the most celebrated formerly were near the island Balireim. 
 Five hundred thousand ducats was then the yearly produce. About 
 one million dollars worth at the present time are exported. The island 
 Kharack now produces the most considerable quantity. The principal 
 market is at Maskate; from thence they are brought to Surat. The 
 mode pursued in those countries is in canoes, holding fifteen men, six 
 of whom are divers: the shells caught during the day are delivered to 
 a surveyor, when they are opened on a white cloth, and whoever finds 
 one of some value puts it in his mouth, to give it, as they say, a 
 “ better water.” The greatest harvests are generally after many rains, 
 and the largest Pearls are mostly found in the deepest water. At 
 Ceylon the pearl fisheries are now considerable, particularly in the bay 
 Condeatchy. The shells are there left to reach the age of seven or 
 eight years, and in the fourth year they have small Pearls, sometimes 
 a hundred and fifty. They fish yearly, in the month of May, during 
 four weeks. In the year 1804, eight hundred canoes, each with two 
 divers, were engaged. Before the year 1800, the pearl banks were 
 leased to an India merchant for three hundred thousand pagods; and 
 before the arrival of the Europeans to India, the same bank was used 
 every twenty or twenty four years ; when under the Portuguese, every 
 ten, and under the Dutch every six years. In 1800, the produce was 
 from one hundred to one hundred and fifty thousand pounds sterling. 
 
 Japan has some pearl banks which are however, not much sought, 
 just like the Nipthoa lake in Chinese Tartary. America did send 
 in the sixteenth century, Pearls to the amount of eight hundred thou¬ 
 sand dollars to Europe. The shells were mostly collected from Cape 
 Paria to Cape Yelo ; round the islands Margaretha, Cubagna, Cocher 
 Punta, Aragy, and at the mouth of Rio la Hacha, from which latter 
 locality and the Bay of Panama, Europe is now mostly supplied ; the 
 former localities having long been relinquished, on account of the small 
 produce ; too many shells having been removed at one time, thereby 
 retarding the growth of Pearls. Panama sends, within a few years 
 past, about one hundred thousand dollars worth of fine Pearls to Eu¬ 
 rope, the trade being carried on by my friends, Messrs. Plise, of Pan¬ 
 ama. The coast of Florida is said to have been very lucrative to the 
 Indians, in a pearl fishery, which, however, does not prove so now 
 since the settlement of civillized people. 
 
THE FOUNTAIN. 
 
 TRANSLATED FOR THE “ VALLEY ARGUS” FROM 
 
 In th e Baden's fragrant shadow 
 Stands our fountain by the way. 
 And the birds sing there so sweetly, 
 Oh I how sweetly none can say. 
 
 plied from the river Conway in Wales ; 
 London market, between the years 1761 
 : ten thousand pounds sterling; but the 
 e found in the Elster river, in the kingdom 
 at the borders of Bohemia to Elsterberg, 
 carried on since 1621, with some advan- 
 3 Pearls found there were valued at fifty 
 the river Watawa in Bohemia, and in the 
 l to Frauenburg, Pearls are found of great 
 qual in price the Oriental Pearls. Also at 
 ptimes found superior to the Oriental in lus- 
 
 APPENDIX. 
 
 153 
 
 To the fountain came a maiden, 
 
 Bore two pitchers in her hand ; 
 Quickly would she stoop to fill them 
 hen a youth before her stands. 
 
 “Dearest mother, do not chide me, 
 Thou thyself didst send me there. 
 
 It may be they stood there chatting; 
 Late returned the maiden fair. 
 
 Berlin, June 27. 1876, 
 
 Lightly trips one to the fountain 
 Heavy weighted home must go, 
 
 And how charmgingly those birds sing, ~ 
 Mother, nay, thou dost not know!” 
 
 tre ; and at Oelsnitz a considerable pearl fishery is carried on. Most 
 of the rivers of Sweden, Lapland, Finland, Poland, Norway, Jutland, 
 Silesia, and other places contain Pearls, but they are not collected. 
 
 The price of Pearls used formerly to be determined like that of the 
 
 Diamond, from one carat upwards, viz.; if the carat is fixed at five 
 dollars, and a Pearl weighs four carats, take the square, or sixteen, 
 multiplied by five, which is equal to eighty ; so that a Pearl of four 
 carats was estimated at eighty dollars. 
 
 I am informed by Mr. Plise, who just now brought a considerable 
 quantity of Pearls from Panama, that he receives four dollars per grain 
 in England, for those of good size and quality. A Pearl which Pliny 
 valued at three hundred and seventy five thousand dollars of our 
 money, Cleopatra is said to have dissolved at a banquet, and drank off 
 to Mark Anthony’s health. The Peregrine which was found in 1574 
 near Margarita, and given to Philip II. of Spain, was of pear-form, the 
 size of a pigeon’s egg, weighed twenty-five carats, and was valued at 
 fifteen thousand ducats. 
 
 Pope Leo bought a Pearl for eighty thousand crowns. Tavernier 
 describes one belonging to the king of Persia, which is said to have 
 cost one million six hundred thousand livres. Portugal has a Pearl in 
 its treasury of the size of a pear. Julius Cesar bought a Pearl from 
 Servilia, the mother of Brutus, for one hundred and fifty thousand 
 crowns. Two Greeks residing in Moscow, are in possession of a Pearl 
 weighing twenty seven seven-eighth carats. 
 
 For restoring Oriental Pearls to their original lustre, lost in process 
 of time, the following process is adopted in Ceylon: the Pearls are 
 allowed to be swallowed by chickens, which are then killed, and the 
 Pearls are an hour afterwards taken out of the stomach, when they 
 are as white and lustry as if just taken from the shell. 
 
 T 
 
154 
 
 APPENDIX. 
 
 ARTIFICIAL PEARLS. 
 
 Artificial pearls or beads are of various kinds, most generally a solid 
 mass of glass, and a hole drilled in them; or they are blown hollow, 
 and then filled out with metallic lustry grains, wax, or else with the 
 fine scales of the bleak fish, which have a silvery and pearly lustre. 
 The same scales are likewise used to coat beads of gypsum or alabas¬ 
 ter, which is soaked in oil, and then covered with wax for giving to 
 it a pearly appearance. The Roman beads are made in this manner ; 
 the scales are dissolved either in liquid ammonia or vinegar, and the 
 solution or liquid is used for covering those artificial beads. The 
 Turkish rose beads are made of an odoriferous paste, and are turned 
 afterwards like those of corals, amber, agate, or other hard substances. 
 The knitting beads are sold in meshes of one hundred and fifty or 
 twenty strings, of fifty beads each, of various colours ; and the large 
 glass-beads in meshes of twelve strings. There are numerous manu¬ 
 factories in Germany and Italy of the various kinds of beads; which 
 are used to a very great extent both in Africa and North and South 
 America. Germany exports yearly from its different manufacturing 
 places, such as Heidelberg, Nurenberg, Sonnenberg, Meistersdorf in 
 Bohemia, and Mayence, more than a million dollars worth. In 
 Venice are large establishments for the finest cut beads. 
 
 Nurenberg manufactures, besides the glass beads, considerable 
 quantities of amber beads. In Gablontz, in Bohemia, more than six 
 thousand persons are engaged in the manufacture of beads, that are 
 made of pure glass or of a composition. From the glass houses, which 
 are very numerous in Bohemia, the rods of different sizes are delivered 
 to the glass mills for cutting, which is performed by water power or by 
 hand. In 1828 there were, in that neighbourhood, one hundred and 
 fifty-two mills in full operation ; a number of glass blowers were like¬ 
 wise engaged, who possess great dexterity in blowing the small beads 
 with the assistance of a small blow-table. In the manufactory of 
 George Benedict Barbaria, at Venice, six hundred varieties of beads 
 are constantly making; and that of Messrs. Gaspari and Moravia, 
 manufactures, besides the beads, every article of jewellery from the 
 same material. 
 
 The rose beads of Steffansky and Tanssig are made of bread crumbs 
 which are beaten up with rose water in a wooden mortar, until they 
 become a uniform mass, to which is added some otto of roses and drop 
 lake, when it is made into beads with dissolved gum tragacanth; for 
 the black rose beads, Frankford black is substituted for the drop lake. 
 
APPENDIX. 155 
 
 Lamaire, of France, manufactures beads equal in lustre and beauty 
 to the real pearls. He adds to 
 
 1000 ounces of glass beads, 
 
 3 “ fish scales, 
 
 l “ fine parchment glue, 
 
 1 “ white wax, 
 
 1 “ pulverized alabaster, 
 
 with which he gives them an external coating. 
 
 Rouyer manufactures his beads also in France, from opal, which he 
 covers with four or five layers of dissolved isinglass, and then with a 
 mixture of a fat oil, spirits of turpentine and copal, to prevent their 
 becoming moist. In order to render them of the peculiar lustre of 
 the oriental Pearls, they are covered with a coloured enamel. The 
 opal is fused into rods by a lamp, over which is laid a brass wire to 
 support it; the wire is held in one hand and the opal with the other, 
 and the wire is then kept turning until the bead has the desired size 
 and roundness ; if a coloured enamel is to be applied, the beads are 
 made but half the required size, which being done, it is once more 
 covered with the opal, then the solution of isinglass is used, and lastly 
 the varnish. Beads made in this manner are with difficulty distin¬ 
 guished from the oriental Pearls. 
 
 The best method of obtaining the artificial Pearls is certainly by 
 means of pulverized real Pearls. Either (he smallest, or the deformed 
 large specimens, may be reduced to a fine powder, and then soaked in 
 vinegar or lemon-juice, and the paste made with the gum tragacanth, 
 may be cut out with a pill machine, or a silver mould of any desired 
 size, and when a little dry, they are to be enclosed in a loaf which has 
 to be baked in an oven; by tin amalgam, or by the silver of the scales 
 of young fish, the lustre may be obtained. 
 
 CORALS. 
 
 The Corals are zoophytes, whose calcareous habitations are like 
 vegetable branches. They live in the sea, adhering to rocks, stones, 
 or vegetables, and shoot to the surface of the water in tubiform stems 
 with branches, generally coated with a gelatinous or leathery skin 
 that encloses a cartilaginous marrow composed of many cells, inha¬ 
 bited by the animals, which propagate in sprouts from eggs, so fast, 
 that small reef-rocks are formed, which in the course of time grow to 
 islands. 
 
 The Red Coral or Precious Coral, (Iris nobilis,) belongs to that 
 family of zoophytes which live mostly in the cavities of rocks in the 
 
156 
 
 APPENDIX. 
 
 sea ; the stem is always of a beautiful red colour, rarely white ; quite 
 compact, striated at the outside, of entire calcareous composition; it 
 grows one foot high and an inch thick. The stem is covered with a 
 leathery crust, containing open warts of eight teeth, in which the 
 animals or polypus with their eight arms, are situated ; the arms are 
 whimpered, and the animal grows very slowly. 
 
 The red Coral is fished up with nets of strong ropes, fastened on 
 large wooden cross beams kept in the water over those places where 
 Corals are known to be fastened, when an expert diver contrives to 
 entangle the nets in the reefs: the nets are then drawn up, and the 
 Corals that may be attached, are cleaned, assorted, and sold to the 
 manufacturers. 
 
 The Red Corals are distinguished by their native countries ; 
 
 1. The Barbarian, which are the thickest and purest. 
 
 2. The Corsican, which are the darkest, but not so thick, and 
 
 less pure. 
 
 3. The Napolitan, and that from Ponza, which are clear, and 
 
 pretty thick. 
 
 4. The Sardinian, which are thick and clear. 
 
 5. The Catalonian, which are nearly as dark as the Corsican, but 
 
 mostly thin. 
 
 6. The Trapanian Corals are procured at Trapani in Sicily, 
 and are somewhat preferred at Leghorn. 
 
 The darkest Corals are most liable to be worm-eaten. 
 
 The polished Corals are generally sold in bundles, which consist 
 of a certain quantity of strings, and a certain weight. They are 
 strung in Leghorn, either of various or equal thicknesses, which latter 
 are then of various sizes, and the bundles receive their names accord¬ 
 ingly ; Grossezze, Mezzanie, Filotti, Capiresti, &c. The thickest 
 Corals are put up in one string, resembling a tail, and are called 
 Codini; the smallest are called Smezzati. 
 
 At Genoa the various large Corals are called Mezzanie; the uniform 
 large, Filze; and the uniform small, Migliari. 
 
 According to colour they are distinguished at Leghorn ; the darkest 
 red are called Arcispiuma, which are the dearest; and then Primo, 
 Secundo, Terzo, Quarto, Coloro or Sangue, Chiari, Moro, Nero, &c. 
 
 According to form, they are called round (tondi), cylindrical round 
 (boticelli). The former form are sent to all parts of the world, 
 whereas the latter are only sent to Poland. The large Boticelli are 
 put up in meshes of twelve pounds, containing 36 strings; and the 
 middle size of the Boticelli are in meshes of six pounds, containing 
 
APPENDIX. 
 
 157 
 
 sixty strings ; those Boticelli which are still larger, are called Olivatti, 
 and are only sent to Africa ; those which are globular and not drilled, 
 are called Pallini altorno, and are sent principally to China, where the 
 favourite colour is the rose-red, and the most perfect kind. 
 
 The sound Corals are called Netti, and the worm-eaten, Camolatti, 
 which latter are mostly sent to the East Indies. 
 
 The tops of the branches are called dog teeth or dent’s cane, and 
 the thick ends of the branches are called maometti; both kinds are 
 perforated lengthwise, and are used in Barbary as ornaments for 
 horses. The fine large Coral Stems which are suitable for specimens 
 in the cabinets of Natural History are called, in Marseilles, Chouettes. 
 
 There are one hundred varieties of shades of Red Coral distin¬ 
 guished at Marseilles. 
 
 The Corals are principally used for ornaments, and although not 
 highly esteemed in Europe or this country, are much more so in the 
 East Indies, China and Africa, where they are preferred to the 
 Diamond. Almost every East India lady wears a bracelet or neck¬ 
 lace of Corals. 
 
 The White Coral has its origin from the eight star Coral ( madre- 
 pora oculta ); and the Black Coral from the black horned Coral 
 (gorgonia antipotlies ). The Medusa head (cuput medusa ), called 
 the Sea Polen belongs likewise to the Coral family, and consists of 
 sixty-two thousand six hundred and sixty-six articulated members. 
 
 The Corals are fished for on the coasts of Barbary, between Tunis 
 and Algiers; in the latter state is Bona, the principal station, and 
 the French have it also at Basteon de France. 
 
 The monopoly was purchased by France since the beginning of 
 the 17th century, at eighteen thousand dollars annually, and by 
 England since 1806 for fifty thousand dollars. 
 
 There is, at Bona, a summer fishery, from the 1st of April to the 
 1st of October, which occupied in 1821 thirty French, seventy Sardi¬ 
 nian, thirty-nine Tuscanion, eighty-three Napoiitan, and nineteen 
 Sicilian ; in all two hundred and forty one barks, of two thousand and 
 twenty-three tons capacity, with two thousand two hundred and 
 seventy-four men, who fished forty-four thousand two hundred pounds 
 of Coral, at a value of two million four hundred thousand francs. 
 The winter fishery of the same year occupied three French barks, 
 each with nine men, and they obtained six hundred and eighty 
 pounds of Corals. 
 
 The principal manufactories of Corals are now at Leghorn, where 
 this branch of business has been carried on for two hundred years 
 
I5S 
 
 APPENDIX. 
 
 past, both then and at the present day by the Jews. There were 
 formerly twenty establishments which have lately been much dimin¬ 
 ished. 
 
 They are sent principally to China, the East Indies and Arabia, 
 partly by the way of London and partly by Moscow, Aleppo and 
 Alexandria; many Corals are likewise sent to Poland. 
 
 Genoa has a few manufactories, in which the Sardinian Corals are 
 mostly wrought. At Marseilles is a large manufactory ever since 
 1780, and at present the only establishment of the kind in France. 
 
 The East Indies consume, according to the statement of Le Goux 
 de Haix, nearly four million francs worth. 
 
 The Corals are worn in the East as ornaments in the turbans, and 
 the Arabs bury the Coral with their dead. 
 
 A large Coral from the manufactory at Marseilles was sold in 
 China, to a Mandarin for twenty thousand dollars. 
 
 The price of Coral has, within some years, much depreciated. 
 
CONTENTS 
 
 Adularia 
 
 Agate 
 
 Agate-Chalcedony 
 
 Alabaster 
 
 Alabastro Agato - 
 Almandine Ruby 
 Amazon Stone 
 Amber - 
 American Marbles 
 Amethyst 
 Anthracite Coal - 
 Antique Porphyry - 
 Apatite 
 Aplome - 
 Apostle Gems 
 Apyrite - - 
 
 Aquamarine 
 Aquamarine Chrysolite 
 Armenian Stone 
 Artificial Aquamarine 
 
 - Emerald 
 
 --— Pearls 
 
 - Ruby 
 
 - Sapphire 
 
 - Syrian Garnet - 
 
 - Topaz 
 
 Augitic Sienite 
 
 Avanturin 
 
 Axinite 
 
 B 
 
 Beryl 
 
 Black Amber 
 Black Glass Lava. 
 Bloodstone 
 Bohemian Diamond. 
 
 - Garnet - 
 
 -Topaz 
 
 
 page. 
 
 Bottlestone 
 
 Ill 
 
 Brazilian Emerald 
 
 - 84 
 
 -Sapphire 
 
 73 
 
 - Topaz 
 
 - 73 
 
 —-Tourmaline 
 
 84 
 
 Brecciated Porphyry 
 
 - 145 
 
 Brilliants 
 
 37 
 
 Brillionets 
 
 - 38 
 
 Bristol Marble 
 
 142 
 
 Brown Quartz 
 
 - 87 
 
 Burning Gems 
 
 147 
 
 C 
 
 
 Cabochon Cut 
 
 - 49 
 
 Cachelong 
 
 109 
 
 Cairn Gouram 
 
 - 86 
 
 Calcareous Spar 
 
 137 
 
 Cannel Coal 
 
 - 135 
 
 Carara Marble 
 
 140 
 
 Carneleon - 
 
 95 
 
 - Onyx 
 
 - 96 
 
 Cat Sapphire 
 
 65 
 
 Cat’s Eye 
 
 - 138 
 
 Ceregat 
 
 94 
 
 Ceylonian Chrysolite 
 
 84 
 
 - Opal 
 
 - 113 
 
 - Tourmalin 
 
 84 
 
 Chalcedony 
 
 - 94 
 
 Chalcedonyx 
 
 94 
 
 Change of Colour 
 
 - 23 
 
 Chemical Characters 
 
 25 
 
 -- Composition 
 
 - 25 
 
 Chlorophane 
 
 126 
 
 Chrysoberyl 
 
 - 70 
 
 Chrysolite 
 
 102 
 
 Chrysoprase 
 
 - 101 
 
 Cinnamon Stone - 
 
 82 
 
 Circle Agate 
 
 - 98 
 
 page. 
 
 113 
 
 97 
 
 94 
 
 129 
 
 129 
 
 71 
 
 114 
 
 129 
 
 140 
 
 88 
 
 135 
 
 145 
 
 143 
 
 81 
 
 - 28 
 
 84 
 
 78 
 
 78 
 
 119 
 
 ■ 46 
 
 46 
 
 154 
 
 46 
 
 46 
 
 46 
 
 - 46 
 
 147 
 
 91 
 
 112 
 
 77 
 
 134 
 
 111 
 
 97 
 
 - 86 
 
 81 
 
 - 86 
 
160 
 
 CONTENTS. 
 
 page. 
 
 Citrin - - - 86 
 
 Cleaning of Gems - 44 
 
 Cleavage of Gems - 44 
 
 - Minerals - 12 
 
 Cloudy Agate - - 98 
 
 -Chalcedony - 94 
 
 Cohesion - - 14 
 
 Colouring Materials - 43 
 
 Colours - - - 16 
 
 Common Corundum - 69 
 
 - Felspar - 114 
 
 - Opal - 107 
 
 - Quartz - 89 
 
 Corals - - 154 
 
 Coral Agate - - 98 
 
 Cordierite - - 107 
 
 Cornalines de vieille roche - 95 
 
 Corundum - - 107 
 
 D 
 
 Dariainur Diamond - 32 
 
 Definition of Gems - 9 
 
 Dentritic Agate - - 98 
 
 Derbyshire Spar - - 126 
 
 Diamond Grinder - 32 
 
 Diamond - - 51 
 
 Dichorite - - 103 
 
 Division of Gems - 10 
 
 - Minerals - 9 
 
 Drilling of Gems - 41 
 
 Doublettes - - 47 
 
 Double facet cut - - 40 
 
 E 
 
 Egyptian Jasper - 92 
 
 - Pebble - - 92 
 
 -Marble - 104 
 
 Electric Shorl - - 84 
 
 Elongated facet cut - 39 
 
 Emerald - - 75 
 
 Engraving of Gems - 41 
 
 External characters of Minerals 10 
 Eye Agate - - 98 
 
 -Stone - - 98 
 
 F 
 
 Felspar - - 112 
 
 Figure Agate - - 98 
 
 Fish Eye - - 113 
 
 Fluorspar - - 125 
 
 Fortificational Agate - 98 
 
 Fire Opal - - 107 
 
 Fracture of Minerals 
 Fragment Agate - 
 Forms of Diamond 
 
 -Gems 
 
 -Minerals 
 
 French Shell Marble 
 G 
 
 page. 
 
 12 
 
 - 98 
 37 
 
 - 38 
 10 
 
 - 142 
 
 Garnet - - - 80 
 
 Gem Grinder - - 33 
 
 Gems for Optical Purposes - 48 
 
 Geographical Distribution 26 
 
 Geological Characters - 26 
 
 Glyptic Art - 30 
 
 Gold Stone - - 92 
 
 Goutte d’ Eau - 73 
 
 - de Sang - 71 
 
 Girasol Sapphire - 66 
 
 Green Mica - - 144 
 
 Grinding of Gems - 31 
 
 -Materials - 42 
 
 H 
 
 Hair Stone - - 87 
 
 Haiiyne - - 117 
 
 Hard Gems - - 14 
 
 Hardness of Minerals - 13 
 
 Hatchet Stone - - 105 
 
 Heleotrope - - 97 
 
 History of Gems - - 28 
 
 Hornstone 93 
 
 Hyacinth - - - 79 
 
 Hydrophane - - - 108 
 
 Hypersthene - - 107 
 
 I 
 
 Iceland Agate - - 111 
 
 Idocrase - - 117 
 
 Imitation of Gems - - 45 
 
 Indian Topaz - - 73 
 
 Indicolite - - 84 
 
 Iolite - - 103 
 
 Iridescence - - - 23 
 
 Iridescent Quartz - 86 
 
 Italian Marble - - 140 
 
 - Shell Marble - 142 
 
 J 
 
 Jade ... 135 
 Jasper - - 92 
 
 - Opal - - 111 
 
 Jet .... 134 
 
CONTENTS. 
 
 161 
 
 
 
 page. 
 
 Jewellery Grinder 
 Jeweller’s Wax 
 
 
 33 
 
 
 - 44 
 
 K 
 
 
 
 Kyanite 
 
 - 
 
 122 
 
 Kuinur Diamond 
 
 - 
 
 32 
 
 L 
 
 
 
 Labrador 
 
 - 
 
 115 
 
 Laconia Marble 
 
 
 - 144 
 
 Landscape Agate 
 
 - 
 
 98 
 
 Lapis Lazuli 
 
 
 - 119 
 
 Lapidary’s Apparatus 
 
 - 
 
 40 
 
 Largest Diamonds 
 
 
 - 63 
 
 - Sapphire 
 
 - 
 
 69 
 
 Lava 
 
 
 - 135 
 
 Lepidolite 
 
 - 
 
 143 
 
 Limestone 
 
 
 - 137 
 
 Lombardy Marble 
 
 - 
 
 140 
 
 Loss of Colour 
 
 
 - 23 
 
 Love’s Arrows - 
 
 - 
 
 87 
 
 Lumachelle Marble 
 
 
 - 142 
 
 Luni do. 
 
 - 
 
 140 
 
 Lustre of Gems 
 
 
 - 21 
 
 Lustre Shine 
 
 - 
 
 21 
 
 M 
 
 
 
 Magnetism 
 
 - 
 
 24 
 
 Male Sapphire 
 
 
 - 65 
 
 Malachite 
 
 - 
 
 126 
 
 Marble 
 
 
 - 137 
 
 Marekenite 
 
 - 
 
 111 
 
 Markasite 
 
 
 - 144 
 
 Mica 
 
 - 
 
 143 
 
 Mixed Facet Cut 
 
 
 - 39 
 
 Moon Stone 
 
 - 
 
 113 
 
 Moccha Stones 
 
 
 - 94 
 
 Moss Agate 
 
 - 
 
 98 
 
 N 
 
 
 
 Natrolite 
 
 - 
 
 125 
 
 Natural History 
 
 
 - 9 
 
 Needle Stone 
 
 - 
 
 89 
 
 Nephrite - 
 
 
 - 135 
 
 New Haven 
 
 - 
 
 141 
 
 Nomenclature of Gems 
 
 
 - 27 
 
 0 
 
 
 
 Oberstein 
 
 - 
 
 99 
 
 Obsidian 
 
 
 - Ill 
 
 Occidental Diamond 
 
 - 
 
 86 
 
 -Topaz 
 
 
 - 86 
 
 Onyx 
 
 -- 
 
 97 
 
 Opal - 
 
 
 ► 104 
 
 
 page. 
 
 Oriental Amethyst 
 
 65 
 
 - Aquamarine 
 
 - 65 
 
 -Chrysolite 
 
 65 
 
 -Emerald 
 
 - 65 
 
 -— Hyacinth 
 
 65 
 
 -Ruby 
 
 - 65 
 
 -Sapphire 
 
 65 
 
 -Topaz 
 
 - 63 
 
 P 
 
 
 Panno di Morto 
 
 142 
 
 Pastes 
 
 - 45 
 
 Pavillion Cut 
 
 39 
 
 Pearls - 
 
 - 148 
 
 Pebbles 
 
 13 
 
 Peliome 
 
 - 103 
 
 Petrefact Agate 
 
 98 
 
 Philadelphia Marble 
 
 - 140 
 
 Phosphorescence 
 
 23 
 
 Pisolite 
 
 - 142 
 
 Pitch Opal 
 
 109 
 
 -Coal 
 
 - 129 
 
 Plaster of Paris 
 
 129 
 
 Plasma 
 
 - 92 
 
 Play of Colours 
 
 23 
 
 Plumose Mica 
 
 - 144 
 
 Polishing Materials 
 
 42 
 
 Porphyry 
 
 - 145 
 
 Porphyritic Sienite 
 
 149 
 
 Potomac Marble 
 
 149 
 
 Prase 
 
 - 91 
 
 Precious Gems 
 
 9 
 
 - Opal 
 
 - 105 
 
 -Serpentine 
 
 136 
 
 Price of Gems 
 
 - 42 
 
 - Sapphire 
 
 68 
 
 Pseudo Diamond 
 
 86 
 
 Punctated Agate 
 
 98 
 
 Panama 
 
 135 
 
 Pyrites 
 
 144 
 
 q 
 
 
 Quartz 
 
 85 
 
 R 
 
 
 Rainbow Agate 
 
 98 
 
 -Chalcedony 
 
 - 94 
 
 Raising the Colour 
 
 43 
 
 Red Sapphire 
 
 65 
 
 Refraction 
 
 22 
 
 Regent Diamond 
 
 32 
 
 Ribband Jaspar 
 
 - 93 
 
 V 
 
162 
 
 CONTENTS. 
 
 
 page. 
 
 Ribband Agate 
 
 97 
 
 Rock Crystal 
 
 - 85 
 
 Rock of Giberaltar 
 
 143 
 
 Rose Diamond 
 
 38 
 
 -Manganese 
 
 144 
 
 Rosso Antico 
 
 140 
 
 Rubellie 
 
 34 
 
 Ruby Spinelle 
 
 71 
 
 Ruin Agate 
 
 98 
 
 S 
 
 
 Sapphire 
 
 64 
 
 Sapphirine 
 
 94 
 
 Sardonyx 
 
 96 
 
 Satin Gypsum 
 
 128 
 
 - Spar 
 
 128 
 
 Sawing of Gems 
 
 41 
 
 Saxon Topaz 
 
 73 
 
 Scale of Hardness 
 
 13 
 
 Scotch Pebble 
 
 - 86 
 
 Sculpture Gems 
 
 30 
 
 Semi-Carneleon 
 
 - 94 
 
 -Hard Gems 
 
 14 
 
 -Opal 
 
 - 109 
 
 Serpentine 
 
 136 
 
 Setting of Gems 
 
 44 
 
 Shell Agate 
 
 - 92 
 
 -Marble 
 
 141 
 
 Siberian Aquamarine 
 
 - 78 
 
 —-— Topaz 
 
 73 
 
 -Tourmaline 
 
 - 84 
 
 Siberite 
 
 84 
 
 Sienite 
 
 146 
 
 Smell - 
 
 25 
 
 Smoky Quartz 
 
 87 
 
 - Topaz 
 
 87 
 
 Soft Precious Stones 
 
 14 
 
 Specific Gravity of Gems 
 
 20 
 
 Spinelle 
 
 71 
 
 St. Stephen’s Stone 
 
 94 
 
 Stalactite 
 
 137 
 
 Stalagmite 
 
 137 
 
 Star Agate 
 
 98 
 
 -Sapphire 
 
 86 
 
 Steinliilite 
 
 103 
 
 Strass - - 
 
 45 
 
 
 page. 
 
 Striped Jasper 
 
 93 
 
 Sulphuret of Iron 
 
 144 
 
 Sun Stone - 66 and 113 
 
 Surface of Minerals 
 
 13 
 
 Syrian Garnet 
 
 81 
 
 T 
 
 
 Table of Colours 
 
 20 
 
 -Cut 
 
 - 40 
 
 -Diamond 
 
 38 
 
 Taste 
 
 - 26 
 
 Thumerstone 
 
 12 
 
 Topaz 
 
 - 72 
 
 Touch 
 
 25 
 
 Tourmaline 
 
 - 83 
 
 Trade in Gems 
 
 43 
 
 Transparency 
 
 22 
 
 Tree Stones 
 
 - 94 
 
 Tube Agate 
 
 98 
 
 Turquoise 
 
 - 123 
 
 U 
 
 
 Ultramarine 
 
 120 
 
 -Artificial 
 
 - 121 
 
 V 
 
 
 Venitian Marble 
 
 140 
 
 Venus Hair - 
 
 - 87 
 
 Verde Antico - 
 
 140 
 
 Vitreous Felspar 
 
 - 114 
 
 Volcanic Lava 
 
 111 
 
 W 
 
 
 Water Drops 
 
 - 73 
 
 -Opal 
 
 113 
 
 -Sapphire - 
 
 - 65 
 
 Wax Opal - 
 
 148 
 
 White Sapphire 
 
 - 65 
 
 Y 
 
 
 Yellow Jasper - 
 
 - 93 
 
 -Quartz - 
 
 86 
 
 Z 
 
 
 Zircon 
 
 - 79 
 


 
 
 
GETTY CENTER LIBRARY