CHAPTER IV. 



COPPER. 



2.04.01. Copper Ores. 



TABLE OF ANALYSES. 



Cu. S. Fe. 



Native copper (generally with some silver) 100. 



Chalcocite, Cu 2 S 79.8 20.2 



Chalcopyrite, CuFeS 2 34.6 34.9 30.5 



Bornite, Cu 3 FeS 3 61.79 25.8 11.7 



Tetrahedrite, 4CuS 8 Sb 2 S 3 (variable) 26.50 Sb' 36.40 26,7 1 .39 



Enargite, Cu 3 AsS 4 (As.l9.1) 48.4 32.5 



Cuprite, Cu 2 O 88 . 8 



Melaconite (tenorite), CuO 79.86 



Malachite, 2CuO+CO 2 +H 2 O 57.4 



Azunte, 3CuO+CO 2 +H 2 O 55.0 



Chrysocolla, CuO+SiO 2 +2H 2 O 36.1 



2.04.02. Example 16, Continued. Pyrite or pyrrhotite beds 

 (veins), with intermingled ehalcopyrite. Whether the deposits 

 are true beds or veins parallel with the stratification is as yet a 

 matter of dispute. The resemblance to magnetite argues a bed, 

 and this view is generally taken by German writers. The Cali- 

 fornia mines occur closely associated with the auriferous (pyritous) 

 quartz bodies, which are always esteemed veins. The interbedded 

 lenticular deposits are placed by themselves as the main example. 

 The undoubted veins like Ore Knob, N. C., are then made a 

 sub-example. Pyrites and pyrrhotite (called mundic by the 

 miners) are the principal constituents of such bodies, but often the 

 copper reaches 4 to 5#, and then they are valuable for copper. 

 The ores are often roasted for sulphurous fumes in acid works, 

 and afterward the residues are returned to the copper smelters. 

 They have been or are being worked for this metal at Capel- 

 ton, Quebec, just north of Vermont. At Milan, N. H., there are 

 several deposits in argillitic schists, and in the same region are 

 numerous other locations. At Yershire, Vt., there is a belt some 



