GRAPHITE 305 



deposits in other states, but none in sufTicient quantity or 

 purity to be of eonniiercial value at the present time. 



In Wisconsin tlie mines near Stevens Point, Portage 

 county, produce graphite which is reported to contain, at 

 times, as much as 74 per cent of carbon. It is utihzed in the 

 manufacture of paint, hibricants, and greases. 



In Michigan there are several thousand acres in Baraga 

 county, composed of a carbonaceous schist without a sign of 

 a vein of graphite. This material is ground for paint and 

 is improper!}^ called graphite. 



In Rhode Island the mines near Cranston have been 

 operated for many years. The graphite shows a structure 

 between scaly and granular, and the grade of the product 

 has not until recently exceeded 55 per cent of carbon, the 

 remainder of the ore being silica and iron oxide, with a trace 

 of sulphur. 



In South Dakota there are several graphite properties 

 in the vicinity of Custer containing promising veins of graphite, 

 one of which is reported to be 4 feet in width and of high grade 

 mineral. At Castle Creek, in Pennington county, 25 miles 

 northwest of Custer, there is a vein which is reported to con- 

 tain 40 per cent of carbon and to be in contact with a 10-foot 

 layer of graphitized slate. 



In New Mexico considerable exploratory work has been 

 done at the graphite properties 8 miles southwest of Raton, 

 Colfax county. 



In Ceylon, which is the chief producer of high grade 

 crystalline graphite, the main deposits are in the western and 

 northwestern provinces. The graphite, which is scaly or 

 fibrous in structure, is found in veins of irregular occur- 

 rence and extent, which break through crystalline rocks 

 of the character of granulite. The minerals associated with 

 graphite in the material which forms the vein are feldspar, 

 rutile, P3^rite, biotite, and calcite. The country rock is often 

 highly decomposed, and then consists mainly of kaolin and 

 similar decomposition products. The formation of graphite 

 in these deposits has been attributed by Dr. Ernst Wein- 

 schenk to the decomposition of vapors carrying carbonic 

 oxide and cyanogen compounds. 



Vol. 6-20 



