Native Copper , Ores of Copper^ and other Minerals. Ill 



of some interest^ that so large a proportion of carbon should be as- 

 sociated in this manner with the ore in question ; nor can I con- 

 jecture by what decomposition it has been produced, unless by 

 that of the carbonate of copper, which may have originally ex- 

 isted in the rock in which this substance is found. 



Carbonates of Copper. — It has already been stated that some 

 of the specimens of native copper are incrusted with the green 

 and blue carbonates of coppf^r. The most interesting locality of 

 these carbonates, however, is on the banks of the Delaware and 

 Raritan Canal, about a mile N. W. of New Brunswick. At this 

 point the strata of shale are nearly horizontal, and alternate with 

 a gray slate containing particles of mica. 



In the cleavages and fissures of this slate, the blue carbonate is 

 found in the form of a crystalline incrustation. These crystals 

 effervesce, and are entirely dissolved in nitric acid. The green 

 carbonate is sometimes associated with the blue. 



This locality is near the bed of a ravine ; and when it is re- 

 membered that the oxide of copper is very common in the rocks 

 of this vicinity, it will not be difficult to account for the forma- 

 tion of these carbonates, which I believe to be constantly going 

 on. Water, charged with carbonic acid, dissolves a portion of 

 this oxide, and whenever circumstances favor the escape of the 

 excess of carbonic acid, these salts are deposited. These min- 

 erals are manifestly the result of precipitation from an aqueous- 

 solution ; and in applying the above explanation, it is only ne- 

 cessary to admit that the carbonates of copper, by an excess of 

 carbonic acid, are rendered soluble in water. 



BisiLicATE OF Copper. — This mineral, which was formerly 

 often labelled phosphate of copper, was first correctly described 

 by the late Prof George T. Bowen. It invests the impure ores 

 of copper found at the Schuyler, the Franklin, and the Bridge- 

 water mines ; but it sometimes also occurs in small veins or 

 masses in the rock, which forms the gangue of these ores. 



The color of this mineral varies from mountain green to a deep 

 bluish green. It is easily broken, and may be scratched by the 

 knife. Fracture, uneven, or somewhat conchoidal. Usually 

 opaque and dull, but sometimes translucent, and with a vitreous 

 lustre. When reduced to powder, and slightly heated in a pla- 

 tina crucible, it assumes a reddish color ; but when the heat is 

 raised, it becomes brown or black. Before the blowpipe on char- 



