Chalcocite - Cu₂S

Habit: Crystals rare, usually massive, compact, with a drusy coating. Black lead-grey. Opaque; Metallic Luster.

Environment: Belongs to a group of sulphide minerals formed at relatively low temperatures, often as alteration products of other copper minerals. Concentrated in secondary alteration zones, can contain considerable higher content of copper than the primary ore. These alteration zones are often Hydrothermal veins with minerals such as quartz, calcite, covellite, chalcopyrite, galena, bornite and sphalerite, as well as chalcocite.

Etymology: Named from the Greek for copper. A common and widely distributed ore mineral of copper