Native Copper, Ores of Copper, and other Minei^als. 109 



The specimens from this locality which I have seen, resemble 

 the copper of cementation. They are all malleable ; but some 

 are much more so than others. Sometimes a thin plate of the 

 metal passes through the center, which is incrusted on both sides 

 with the oxide and carbonate, and a little adhering silica ; while 

 at others, the metallic plate is on the outside. An average spe- 

 cimen was subjected to analysis, and gave the following results : 



Copper, - - - - 86.30 



Silica, - - - - 2.55 



Carbonic acid and oxygen, - - 11.15 



100.00 



Or metallic copper about 70, and oxide and carbonate 27.50, in 

 100 parts. 



Red Oxide of Copper. — I have specimens of this mineral 

 from the Schuyler mine, the Bridgewater mine, near Somerville, 

 and from the immediate vicinity of New Brunswick. Some of 

 them have a lead grey color, and a high metallic luster, with an 

 imperfect crystallization. Others, and especially those from the 

 Bridgewater mine, vary in color from purple to brick red, have a 

 compact structure, and are nearly destitute of lustre. The pow- 

 der of all of them is reddish. 



At New Brunswick, this oxide of copper occurs in thin veins 

 in the red shale, and is sometimes accompanied by native copper 

 and by the green and blue carbonates of copper. The color is 

 usually grey, the powder red, and, unlike the native copper, it is 

 brittle, and easily powdered in a mortar. The rock which is im- 

 mediately in contact with this mineral, is of a drab color, and ap- 

 pears as if it had been altered by heat. 



The specific gravity of one of the best specimens that I have 

 obtained from this locality, is 4.758. On being freed as much as 

 possible from the adhering rock, it was found to be composed of 



Red oxide of copper, - - - 91.55 



Silica, &.C. - _ - _ 8.45 



100.00 



A specimen from the Schuyler mine, which was compact, and 

 had a brownish red color, had the following composition, viz. 



