shee Acted No. et September 20, 1921. i "| y) % 6 s/4: y: COMMONWEALTH OF PENNSYLVANTA BuUL ZI DEPARTMENT OF INTERNAL AFFAIRS James F. Woodward, Secretary BUREAU OF TOPOGRAPHIC AND GEOLOGICAL SURVEY George H. Ashley, State Geologist | hy) FBRIDSPAR IN PENNSYLVANIA By. George H. Ashley “-Beldspar Ls) one. or Mie minor minerals produced ey Pennsylvania. The ‘Statets output in 1920. as ancien by the Ue S. Geological Sur- Nres was ‘8, San) tons valued at $81,104. re ant came from the south- ,, eastern part of the State, and chiefly from ghestet and Bataware | counties. | Feldspar is used very extensively in the manufacture of china and porcelain to influence the character of the "mix" as to ey Weay. etc. Its melting point being lower than that of the other Sebitaanta, it serves as a flux to. bind the particles of clay and , ig quartz hioee shat. It has been used a little as a source of aluminum and Seat though hardly with commercial success, It is also used as a binder in making emery wheels; in the manufacture of certain ‘Kinds of gless and enamels; and as a polishing or scouring medium. Being a little less gritty than silica or ground sand, it is suited for use in scouring Soap. Feldspar is a general name for a group of minerals, all of which ve! wees ant hu er ia : Ae “gpotain aluminum, silicon, anda Biygen: and in varying Eianbiees Des two of the elements, pate tn: pete eta: and sodium, Some of the feldspars known as Amazon Bevel bab eecne: and sunstone are used as eems. All-three of these gem stones have been found at Mineral Hill in Delaware County. Peldspar is one of the three principal minerals composing gran- ite and it occurs in crystals in other rocks. The commercial de - posits, however, occur in the form of pegmatite dikes and veins, Most of the deposits are of the usual type of eranite-pepematite, but those in the extreme southwest part of Chester County belong to an entirely eRe tare nwt ype: which may be designated soda pegmatite, its “principal mineral being the soda feldspar, albite. This variety con- tains no Mee) oc : 7 | The ‘Qikes, or ‘veins that have been age are 6 to 25 feet wide and in most places. the - feldspar, fitien is cream to pink or flesh - , . he vie colored,” wae in etystals that, are from oe inch eo 2 inches BCTOSS. © In some. places pire: ‘orystals’l ie a ad Foot. in: diameter eee been found. The places where Poldspar has been maped. in the past and is still to be found are along a line from the Leiperville quarries near Ghanvaus to Upland and Avondale, and in general along Plum Creek in Delaware County. In Chester County it occurs in many localities, as at Union- pie. eervaniee West Chester , and at Brinton's quarry. It occurs in a more or less disconnected line from West Philadelphia to Frank- ford; and from Germantown and Chestnut Hill to the Schuylkill. In recent years it has been mined at Avondale, Toughkenamon, Chatham, New Garden and at West Caln near the Maryland line in Chester County; at Blan in Delaware County; and several places in Montgomery County. : i= ee yi i } at ‘aay ; } ey , ‘ey, ry ‘ P erg my 59 cp) Farnip nat Olt Ae WANE in i a t we a ¥ VF y | " Pal Ly ‘'D. Wik nit tie \ i) A \ : ‘ ie "UNIVERSITY OF ILLINOIS-URBANA rer re | | ] 3 0112 077640834 — L { | wy