Mooihoekite to chalcopyrite CuFeS, making it helpful in the study of ore deposits and the study of the central portion of the Cu-Fe-S phase system. Mooihoekite, chalcopyrite, talnakhite, and haycockite all play key roles in the study of ore genesis and beneficiation. Mooihoekite Mooihoekite is a copper iron sulfide mineral with chemical formula of CuFeS. The mineral was discovered in 1972 and received its name from its discovery area, the Mooihoek mine in Transvaal, South Africa. Mooihoekite crystallizes in the tetragonal crystal system. It has a short optical c-axis that is perpendicular to two longer a-axes of equal length. For Mooihoekite,
Chalcopyrite chalcopyrite has no solid solution series with any other sulfide minerals. There is limited substitution of Zn with Cu despite chalcopyrite having the same crystal structure as sphalerite. Minor amounts of elements such as Ag, Au, Cd, Co, Ni, Pb, Sn, and Zn can be measured (at part per million levels), likely substituting for Cu and Fe. Selenium, Bi, Te, and As may substitute for sulfur in minor amounts. Chalcopyrite is present with many ore-bearing environments via a variety of ore forming processes. Chalcopyrite is present in volcanogenic massive sulfide ore deposits and sedimentary exhalative deposits, formed by deposition of