Gould Copper Mine, Ontario, Canada Occurrence
Crystal structure: Tetragonal
Hardness: 3 1/2 - 4
Specific Gravity: 4.2
Steak: Green to Black
Chalcopyrite gets it name from the Greek word Khalkos, meaning copper and pyrite, in which chalcopyrite is tetragonal mineral, usually forming Crystal's shaped like tetrahedra. On freshly broken surfaces, it's usually a brassy yellow, and on broken surfaces it often forms an iridescent tarnish. Although it is not rich in copper, its commonly widespread occurence that makes it the most important copper ore.
Chalcopyrite commonly forms under a variety of environmental conditions, and is also found in hydrothermal ore veins deposited at medium and high temperatures, and as replacements, often associated with large concentrations of pyrite. Chalcopyrite rather has a chemical formula of CuFeS2, and is Opaque to brassy yellow with green to black streaks, and is apart of the Sulfide group of minerals. It typically resembled as a copper-iron sulfide that develops iridescent tarnish on exposure to the atmosphere. This type of tetragonal mineral is known to form tetrahedral Crystal's, which in some cases can be up to 4in (10cm) long on a face. It commonly occurs as a massive aggregate and less frequently as botryoidal masses or as scattered grains in igneous rocks. Chalcopyrite typically forms under a variety of environmental conditions, and is mostly found in hydrothermal sulfide veins as a primary mineral deposit at medium and high temperatures (400°F/200°C), and as replacements. It can also be found as grains in igneous rocks and is an important mineral in porphyry deposits. Chalcopyrite rarely occurs in metamorphic rocks, in which selenium can replace a portion of the sulfur content that its associated with it.