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chalcopyrite(kăl'kəpī`rīt, kăl`kōpī'rīt) or
copper pyrites(pīrī`tēz, pə–), brass-yellow mineral, sometimes with an iridescent tarnish. It is a sulfide of copper and iron, CuFeS2 . It crystallizes in the tetragonal system but is usually found in the massive form. Chalcopyrite is of primary origin and occurs in igneous and metamorphic rocks and in metalliferous veins. It is an important ore of copper and is widely distributed throughout the world.
(also copper pyrite), a mineral, a sulfide of copper and iron, CuFeS2, with small admixtures of Ag, Zn, Au, As, Se, and Sn.
Chalcopyrite crystallizes in the tetragonal system. Its crystal structure is similar to that of sphalerite, but the zinc atoms are replaced by copper and iron atoms. When heated to more than 550°C, chalcopyrite loses some of its sulfur and alters to the high-temperature phase CuFeS1.80, with a cubic sphaleritic cell and a disordered arrangement of atoms. This phase may contain in the form of a solid solution zinc, tin, antimony, and other elements, which upon cooling separate out in native chalcopyrite, forming inclusions of sphalerite, stannite, and tetrahedrite. Chalcopyrite usually occurs in the form of crystalline masses. Well-defined crystals are rare; mechanical twins occur frequently.
Chalcopyrite is a brass-yellow mineral, with a metallic luster. It has a hardness of 3–4 on Mohs’ scale and a density of 4,100–4,300 kg/m3. It is brittle and a semiconductor and an antiferromagnetic.
Chalcopyrite is the most common copper mineral and the principal mineral in copper ores. It is found in deposits of virtually all origins, from magmatic to sedimentary. Copper-nickel deposits, such as the deposits at Monche-Tundra and Noril’sk in the USSR and Sudbury in Canada, where chalcopyrite is found together with pyrrhotite and pentlandite, are associated with magmatic formations proper. Contact-metasomatic deposits are also known.
The principal industrial accumulations of chalcopyrite, however, are related to hydrothermal deposits, such as deposits of pyrite ores (Rio Tinto in Spain and Bor in Yugoslavia) and vein and vein-disseminated ores (Karaoba, Almalyk, Kounrad, Kafan, and others in the USSR, Cornwall in Great Britain, and Butte, Mont., and Bingham, Utah, in the United States), where chalcopyrite is usually associated with pyrite, sphalerite, galena, gray ores, and quartz. In large deposits of copper sandstones, chalcopyrite is accompanied by bornite and chalcocite (at Dzhezkazgan and Udokan in the USSR and the deposits of the Copperbelt of Central Africa). Concentrations of chalcopyrite in sedimentary rocks are usually low, but they may sometimes reach commercially acceptable levels in copper shales, for example, the Mansfeld ore field in the German Democratic Republic. In the course of weathering, pyrite, malachite, limonite, chrysocolla, and other minerals are formed from chalcopyrite.
REFERENCESMineraly: Spravochnik, vol. 1. Moscow, 1960.
Ramdohr, P. Rudnye mineraly i ikh srastaniia. Moscow, 1962. (Translated from German.)
Cabri, L. J. “New Data on the Phase Relations in the Cu-Fe-S System.” Economic Geology, 1973, vol. 68, no. 4.
IU. K. VOROB’EV