Cabinet, 13.1 x 8.8 x 5.8 cm
Rio Tinto mine (Mountain City Copper mine), Mountain City District, Elko Co., Nevada, USA
This appears at first blush to be a solid, sheety specimen of massive copper, but in fact, it is all crystallized. Look closely and you will see that it consists of thousands of massed, tiny, sharp little crystals. There are traces of cuprite on the surface here and there. A heavy specimen, and the great majority of it copper crystals, with only a small proportion of matrix. Ex. Mullane Collection.