GUIDE TO THE MINER A LOGIC COLLECTIONS 



Gl 



in Canada, in parts of New England and in Orange and Putnam 

 counties, N. Y. 



Arsenopyrite is an ore of arsenic. 



Sylvanite (graphic tellurium) (AuAg) Te 2 



Sylvanite represents a group of gold and silver tellurids 

 which has recently developed to considerable importance in the 

 Cripple Creek district of Colorado. Sylvanite contains 62.1$ 

 tellurium, 24.5;/ gold and 13.4$ silver. 



It occurs in flat monoclinic crystals usually grouped in branch- 

 ing forms resembling written characters, it is silver-white to 

 steel-gray in color, inclining to yellow, and has a brilliant 

 metallic luster. 



Sylvanite occurs in Transylvania, California and Boulder 

 county, Col. where it is mined for gold. 



SUL.FO-SALTS 



SULFARSENITES, SULFANTIMONITES, ETC. 

 Bournonite (wheel ore) PbCuSbS 3 



Bournonite is a sulfantimonite of lead and copper and con- 

 tains 42.5$ lead, 13$ copper, 24.7$ antimony and 19.8$ sulfur. 



The orthorhombic crystals are frequently twinned, producing 

 the ''cogwheel" forms from which the species derives its com- 

 mon name. It frequently occurs massive, granular or compact. 

 The color is steel-gray to dark gray and the luster metallic. 



Bournonite is found in Germany, Bohemia, Hungary, Corn- 

 wall, Mexico, Chile; also in Canada, Arizona, Arkansas and 

 Colorado. 



Pyrargyrite (dark ruby silver ore) Ag 3 SbS 3 



Pyrargyrite is a sulfantimonite of silver and contains 17.8^ 

 sulfur, 22.3$ antimony and 59.9$ silver. 



Pyrargyrite crystallizes in the rhombohedral-hemimorphic 

 group of the hexagonal system. The crystals are prismatic 

 with rather flat terminations and are frequently twinned. It 

 is translucent to opaque, of a deep red color by transmitted 

 light and gives a purplish red streak. The luster is metallic 

 to adamantine. 



