Chalcocite (mineral)

Chalcocite crystals a selection of specimens of this crystallized mineral species. Chalcocite is a mineral named after the Greek root χαλκóς (chalkos) for copper, of which it is the principal ore. Here many pieces of collection presented with a description, one or several photos and sometimes a video. These chalcocites are for sale.
Copper sulfide, chemical formula Cu2S, monoclinic crystal system.