88 TUE MINERALS OF CHILE. 



very commonly associated with the red oxide of copper, as heautifully shown by a specimen 

 from Illai)el3 (Coquimbo.) It is also found with coiiper in quartz at AndacoUo, (Coquimbo.) 

 Others of the specimens came from San Jose, San Pedro Nolasco, Hinchado, Higuera, and 

 Aconcagua. 



Med C'opjier. — This mineral is found beautifully crystallized in octahedrons, more or less 

 modified. The most beautiful specimens of this description are from Coquimbo ; other speci- 

 mens are massive and granular. 



Its hardness is 3.5; specific gravity, 5.9. Its color is various shades of bright red, and 

 the crystals are transparent, although, from the exceeding intensity of their color, they must 

 he examined by a strong light. 



This mineral is quite brittle, and is composed of — 



Copper - - - - - - - 88.88 



Oxygen - - - - - - - 11.12 



100.00 



Formula is Cu^ 0. 



It sometimes forms veins, coated with green and blue silicates of copper, in the mines of 

 Camarona and Cortadera, in the province of Coquimbo. In the Andacollo mine it is found pure 

 and abundant, below the oxy-sulphuret, resting on metallic copper, with which it is very com- 

 monly mixed. Aconcagua also afforded specimens. At lUapel it is found, containing native 

 silver. 



Capillary Bed Copjxr. — This beautiful form of the oxide of copper is found in fine delicate 

 rhombohedral crystals. It was found in the cavities of massive specimens of the red copper, 

 from Aconcagua. The crystals are as small as the finest hair, and sometimes half an inch in 

 length. Its color is crimson red; specific gravity, 5.8. Its composition is the same as the last 

 described mineral. 



Tenorite or Bludc Oxide of Cojjper. — This is found massive, almost always mixed with 

 other minerals of copper. It has a black metallic lustre, and when pure contains — 

 Copper ....... 79.86 



Oxygen 20.14 



100.00 



Its formvila is Cu 0. 

 Atacamite. — This mineral was first discovered in the sands of the desert of Atacama, and 



hence its name. It is crystallized in modified rectangular prisms, and rectangular octahedrons. 



Its color is of a dark emerald green, almost black at times. It is translucent; has a hardness 



of from 3 to 3.5, and a specific gravity of about 4.00. It consists of water, chloride and 



oxide of copper, and contains, according to analysis of Ulex — 



Chlorine ------- 16.12 



Oxide of copper ------ 56.23 



Water ------- 11.99 



Copper ------- 14.56 



Silica- ------- 1.10 



100.00 



Correspouiling to the formula Cu CI -[- 3 Cu -j- 3 H. 

 This mineral is also found in the district of Tarapaca. It is ground up in Chile, and is used 

 as powder for letters, under tlie name oi arsenillo. 



