USEFUL METALS 



Character of the Ore Bodies. Primary copper sulphides are 

 found at Cornwall, England, in veins containing cassiterite. In 

 Norway, where primary sulphides occur, tin is absent and the ores 

 are associated with greisen and derived from acid irruptives 

 during their solidification. In Telemarken in Southern Norway 

 copper ores occur with tourmaline in granites, gneisses and 

 schistose rocks. At the Ely mine in Vershire, Vermont, the 

 chalcopyrite is associated also with tourmaline. The ore occurs 



FIG. 81. Polished specimen of copper ore from Rambler mine, Wyom- 

 ing. The dark mineral in corellite. The light is kaolinized feldspar. 

 (After Mineral Resources, 1902, U. S. Geological Survey.) 



in saddle-shaped bodies along the folds in the Vershire schists 

 or in long chimneys at the contact of the intrusive granite with 

 the Vershire schists. Pyrite and pyrrhotite are the common 

 associated sulphides. The granite was the parent home of the 

 copper and the chalcopyrite was deposited under pneumatolytic 

 conditions. This mine was known and worked before copper 

 was discovered in the Lake Superior region. In the earlier days 

 with 16 per cent, copper ore the mine was capable of pro- 



