50 NEW YORK STATE MUSEUM 



Essex county. Mica is found in the pegmatite bodies at Crown 

 Point and Ticonderoga now worked. The chief variety is biotite. 

 Occasional shipments of scrap mica recovered in the milling of feld- 

 spar are made by the Crown Point Spar Co. The material is ground 

 and used in paint. 



Large crystals of biotite have been taken from various localities 

 in the town of Keene. 



Saratoga county. A pegmatite body about 2 miles north of Batch- 

 ellerville, town of Edinburg, was worked some years since by the 

 Claspka Mining Co. for feldspar. Several tons of muscovite were 

 taken out in the course of the operations, the mineral occurring in 

 the spaces between the larger feldspars, or intergrown with the lat- 

 ter. The crystals measure up to a foot or more in diameter and half 

 that in thickness, many bearing very perfect prismatic boundaries. 

 Inclusions of magnetite arranged in regular lines are frequent. The 

 muscovite has little value for sheet cutting, being much fractured 

 and splintery. 



Biotite in sheets up to 2 feet across are also found here. 



Warren county. A pegmatite occurrence near Chestertown has 

 been under development at different times and has afforded small 

 quantities of commercial mica, including muscovite and biotite. The 

 locality is mentioned in the Mining and Quarry Report for 191 1 

 under the head of Feldspar, which also is present in marketable 

 quality. It is 3 miles south of Chestertown on the ridge to the east 

 of the Warrensburg road. Two openings were made over 15 years 

 ago, and in 1913 further work was carried on by C. A. Williams 

 who informs the writer that he secured some merchantable book 

 mica and plans to continue operations during the current season. 

 The main opening is a pit 15 feet wide extended for 75 or 80 feet 

 along the course of the pegmatite which strikes northeast. The full 

 size of the body could not be ascertained at the time the writer 

 visited the locality as only the easterly wall was exposed. The 

 pegmatite is a coarse aggregate of white microcline, quartz and 

 mica. Biotite seems to be chiefly represented near the outcrop, but 

 Mr Williams states that recent work has uncovered muscovite in 

 larger amount. The books run to a foot or so in diameter and 

 usually show fractures or rulings. Black tourmaline occurs spar- 

 ingly in the quartz and feldspar, but it would appear that feldspar 

 of pottery grade may be obtained with a little sorting. A smaller pit 

 lies to the north of the other, the result of the earlier operations, 

 and is thought to be on the same pegmatite body, in which case the 

 occurrence must be quite extensive. 



