136 APPENDIX C. MINERALOGY. 



last disappears altogether; after which the globule swells out into large 

 bubbles and suddenly collapses, and this repeatedly for a number of 

 times, (ten or fifteen,) when it seems to be pure copper. In cooling, 

 however, a thin, light steel-gray pellicle forms upon its surface, which 

 separates by a slight blow with the hammer, revealing a globule of pure 

 copper within. This coating, on being fused with borax, gives rise to 

 a colorless glass, with brilliant points of metallic copper adhering to the 

 support of subjacent charcoal : a fragment heated in a small glass tube 

 before the blow-pipe, enters into fusion and evolves much moisture, 

 which contains traces of hydrochloric acid. The powdered mineral is 

 almost wholly dissolved by ammonia, and the black powder which 

 remains is slowly taken up by warm nitric acid, with the separation of 

 traces of silica. Sulphuric acid dissolves the mineral, with the extrica- 

 tion of hydrochloric acid. Analysis gave the following as the composi- 

 tion of the ore : 



Copper 54.30 



Oxygen and chlorine 36.20 



Water... 9.50 



100.00 



With traces of silica. 



The above is undoubtedly a very valuable ore for copper, as it is very 

 rich in metal, and easy of reduction in the furnace. Numerous speci- 

 mens of the same ore, but very impure from an admixture of fine sand, 

 were embraced in the collection, as coming from Copper creek, four 

 miles from Cache creek. They were in the form of flattened, irregular 

 discs, about two inches across and half an inch thick, having their sur- 

 faces coated by malachite (carbonate of copper) in a pulverulent condi- 

 tion. Along with the above, also, were found similarly shaped masses 

 of an impure black oxide of copper, (coated by malachite,) which had 

 the following composition : 



Copper (with traces of iron) 35.30 to 40.00 



Silica ' 30.60 



Oxygen and water 34.10 



100.00 



It is fusible before the blow-pipe, but does not tinge the flame blue or 

 green. The fused mass bubbles up for a time, and finally yields a 

 globule of copper with a thick crust, which is black, and feebly attracted 

 by. the magnet. A copper ore of the average characters of these flat- 

 tened masses would yield from 33 to 35 per cent, in the large way. 



