THE MINING AND QUARRY INDUSTRY I913 49 



Much of the mica as found in pegmatites and contact zones, even 

 when in large crystals, can not be used in sheet form on account of 

 the numerous fractures and lines that traverse the surfaces. There 

 is great variation in the splitting quality of mica from different 

 places, some examples cleaving readily and cleanly even to very 

 thin sheets and others showing a splintery surface. The average 

 size of sheet that can be obtained largely determines the value of 

 a deposit, since the prices rapidly decrease with the size. The waste 

 in the splitting is sometimes turned into use by converting it into 

 ground mica for which there exists a more or less ready market in 

 the making of lustrous coated papers, lubricants and insulating 

 materials. 



FIELD OCCURRENCE 



'Orange county. Phlogopite of greenish color is found in a pyrox- 

 ene rock near Lake Mombasha, town of Monroe. The locality is 

 mentioned by Beck in the reports of the First Survey as being on 

 the bank of the stream flowing from " Mount Basha " pond, near 

 the Forshee iron mine. It is a contact deposit in limestone of 

 which there are exposures in the vicinity of the mine mentioned and 

 also farther north around the opening of the O'Neil mine. Amphi- 

 bole, pyroxene, garnet and probably magnetite bodies themselves are 

 accompanying results of the contact action. The occurrence is men- 

 tioned by Whitlock 1 as having been worked in 1903. Sheets have 

 been mined that measured as much as three feet in diameter. 



Warzvick. According to Whitlock 2 muscovite occurs near Green- 

 wood lake, 8 miles southwest of Warwick, in a pegmatite vein, the 

 plates reaching a foot in diameter. There are numerous other oc- 

 currences of muscovite in this vicinity, as pegmatite has a wide dis- 

 tribution in the crystalline areas of the Highlands. 



Westchester county. A deposit of mica near Pleasantville was 

 at one time the object of mining operations. The occurrence is in 

 pegmatite and the mica belongs to the muscovite variety. The 

 sheets contain magnetite inclusions. 



Muscovite is found in considerable quantity in parts of the Kinkel 

 feldspar quarry at Bedford, but is not of commercial quality, ex- 

 cept possibly for ground mica. 



Putnam county. The occurrences in this county have not af- 

 forded any commercial mica so far as known. 



1 Minerals Not Commercially Important, 23d Report of the State Geologist 

 Albany, 1904, p. 191. 



2 Op. cit. 



