MINERALS OF CHILE. 61 



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

 existing in secondary stratific porphyry, and sometimes con- 

 taining a notable amount of silver. It is also found abun- 

 dantly 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 cop- 

 per or the oxychloride. The specimens examined were from 

 Copiapo, although there are numerous localities. It is remark- 

 able 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 luster. 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 examined contained from fifty-five to sixty- 

 five per cent, of copper. Three specimens, that have been 

 thoroughly analyzed by M. Domeyko, gave 



Tamaya. Los Sapos. Higuera. 



Copper 66.7 56.1 59.5 



Iron 8.9 17.7 18.2 



Sulphur.. 22.8 23.1 20.5 



Quartz 1.6 3.1 1.8 



99.8 100.0 100.0 



The formula is Fe S+2 Cu 2 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 



