Chalcopyrit

Chalcopyrite (CuFeS2) is a copper iron sulfide mineral and the most important copper ore. The name derives from the Greek chalkos, meaning copper, and pyrites, meaning stone. Chalcopyrite crystallizes in the tetragonal system and commonly occurs as massive aggregates or euhedral to subhedral crystals with a bright brassy yellow color and a metallic luster; it often develops an iridescent tarnish of blues, purples, and golds when exposed to air.

Physically, chalcopyrite has a Mohs hardness of 3.5 to 4 and a specific gravity of about 4.1 to 4.3 g/cm3. Cleavage is indistinct and fracture is uneven. It forms in a variety of hydrothermal environments and is a principal ore in porphyry copper deposits; it is commonly found in association with bornite, chalcocite, sphalerite, galena, malachite, and azurite, among others.

Chalcopyrite is widely distributed geographically and is mined in many countries. Major producers include Chile, Peru, the United States, Australia, Canada, and parts of the former Soviet Union. Economically, it serves as the primary source of copper; concentrates from chalcopyrite are smelted to produce refined copper metal.

Distinguishing chalcopyrite from related minerals such as pyrite can require examination of properties like hardness and staining behavior, as they can appear similar in color in hand specimens. Its abundance and significance in copper mineralogy make chalcopyrite a cornerstone mineral for mining, geology, and ore deposits studies.