Chalcocite, copper sulfide, is an important copper ore mineral. It is opaque, being colored dark-gray
to black with a metallic luster. It has a hardness of 2½ - 3. It is a sulfide with an orthorhombic crystal system. The
term chalcocite comes from the alteration of the obsolete name chalcosine, from the Greek khalkos, meaning copper.
alcocite is sometimes found as a primary vein mineral in hydrothermal veins. However, most chalcocite occurs in the supergene
enriched environment below the oxidation zone of copper deposits as a result of the leaching of copper from the oxidized minerals.
It is also often found in sedimentary rocks.
It has been mined for centuries and is one of the most profitable copper ores. The reasons for this is its
high copper content (67% atomic ratio and nearly 80% by weight) and the ease at which copper can be separated from sulfur.
