CHALCOCITE CRYSTALS, DZEZKAZGAN MINE, DZEZKAZGAN OBLAST, KAZACHSTAN (RARE) (small cabinet)

Chalcocite, a significant copper ore mineral, is composed of copper(I) sulfide (Cu2S). This mineral appears opaque and ranges in color from dark gray to black, exhibiting a metallic sheen. With a hardness rating of 2.5 to 3 on the Mohs scale, it belongs to the monoclinic crystal system. The name chalcocite is derived from the Greek word "khalkos," which translates to "copper." It is also referred to as redruthite, vitreous copper, or copper-glance.