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NEW YORK STATE MUSEUM 



The pegmatite consists of two varieties of feldspar, one a light 

 pink and the other greenish ; also quartz and hiotite, with occasional 

 small crystals of titanite, magnetite, zircon, tourmaline, pyritc and 



Fig. 13 Intrusion of pegmatite in gneiss, near quarry of Crown Point Spar 

 Co., showing the bosslike shape of the pegmatite masses in this section 



chalcopyrite. Bastin reports also the presence of allanite. Chlorite 

 occurs as a secondary development along planes of slipping incident 

 to compression. The quartz and feldspar are rather intimately 

 intermixed, but single individuals of either occur up to 6 or 8 

 inches in diameter. An examination of the feldspars under the 

 microscope show that the pink variety is microcline and the greenish 

 a plagioclase in optical properties close to oligoclase. Most of the 

 iron is present in biotite which is rather abundant though unequally 

 distributed. 



The principal product of the quarry is roofing material but other 

 grades are sold for concrete, poultry grit and enamel wares. The 

 spar for the latter purpose is obtained from sorted material that is 

 free of iron minerals, with microcline as the main ingredient. The 

 biotite is screened out and finds application in paint. 



The pegmatite as quarried is conveyed by an overhead tram to 

 the mill which is situated at the base of the hill close to the lake and 

 railroad. It is there passed through a preliminary crusher of the 

 Blake type, then dried and further reduced by rolls and sized on 

 screens. The pottery grade after crushing and drying goes to a 

 chaser for final reduction. The crushed pegmatite is graded into 

 six sizes of which the coarsest (no. 2) will pass a 2^ mesh screen 



