THE MINERALS OF CHILE. 89 



Copper Glance. — The specimens of this mineral examined were all massive, of a hlack metallic 

 lustre, soft, and easily cut with a knife, having a specific gravity of 5.7. It commonly has 

 green and blue carbonate disseminated through the mass. It is composed of — 

 Copper ---___- 179.8 



Sulphur ------- 20.2 



100.0 



Having for its formula Cu^ S. 



It is most abundant in those mines furthest from the coast, existing in secondary stratific 

 porphyry, and sometimes containing a notable amount of silver. It is also found abundantly 

 in the mines of Chile that are near the coast, and are in dioritic and porphyritic rocks ; but 

 in them it is rarely found pure, being almost always mixed with the black oxide of copper 

 or the oxy-chloride. The specimens examined were from Copiapo, although there are numerous 

 localities. It is remarkable that, at San Antonio, this mineral is associated with native silver, 

 and yet often contains hardly more than one thousandth of this latter metal. Specimens of pure 

 sulphuret of copper are found, in which metallic silver is imbedded in the form of grains or 

 little plates; and the same sulphuret contains grains and plates of native copper, entirely 

 separate from the silver. 



Erubescite or Purple Copper. — This is one of the most abundant of the minerals of copper 

 found in Chile. It is procured in large quantities at the mines of Tamaya in Coquimbo, 

 Los Sapos, and Higuera. No crystals were seen. It is massive, of a purplish, variegated 

 color, with a metallic lustre. It is brittle, and not very hard. When the surface is freshly 

 broken, it is of a brass color, that very often tarnishes, acquiring a purplish hue. The massive 

 varieties of this mineral always vary more or less in their composition. The specimens exam- 

 ined contained from 55 to 65 per cent, of copper. Three specimens, that have been thoroughly 

 analyzed by M. Domeyko, gave — 



Copper 



Iron - - - 



Sulphur 



Quartz 



The formula is Fe S + 2 Cu^ S. 

 This mineral furnishes a great deal of the copper produced in Chile. 



Copper Pyrites. — This is the most abundant copper ore of Chile, and is found in immense 

 quantities in the province of Coquimbo ; some of it, as that from Tamaya, contains .0025 

 per cent, of silver, while that of another mine contains gold. All the specimens were massive, 

 of a brass yellow color, metallic lustre, fresh fractured surfaces tarnishing readily. In fact, it 

 possesses all the known characteristics of this mineral . as found elsewhere. Its composition, 

 when perfectly pure, is — 



Sulphur 35.05 



Copper 34.47 



Iron -------- 30.48 



100.00 

 12* 



Tamaya. 



66.7 

 8.9 



Los Sapos. 



56.1 



17.7 



Higuera. 



59.5 

 18.2 



22.8 



23.1 



20.5 



1.6 



3.1 



1.8 



99.8 



100.0 



100.0 



