Chalcopyrite
Image: <a href="//commons.wikimedia.org/wiki/User:Islam90" title="User:Islam90">Islam90</a> (CC BY-SA 4.0)
Mineral NameChalcopyrite
Chemical FormulaCuFeS2
Mohs Hardness3.5
Crystal Systemtetragonal
Lustermetallic
Streak Colorgreenish-black
Cleavagepoor/indistinct on {011}
Fractureuneven to conchoidal
Specific Gravity4.2
Colorsbrass-yellow, golden-yellow, often tarnishes to iridescent blue, purple, or red
Transparencyopaque
Type LocalityWorldwide, common in many major copper deposits (e.g., Bingham Canyon, Utah, USA; Chuquicamata, Chile; Sudbury, Ontario, Canada)
Mineral GroupSulfides
Usesprimary ore of copper, collector specimens
Associated Mineralspyrite, sphalerite, galena, quartz, calcite, bornite
Raritycommon
Description
This image shows a microscopic view of chalcopyrite under polarized light, appearing as a field of yellowish grains with darker inclusions. Macroscopically, chalcopyrite is a brass-yellow mineral with a metallic luster.
Geological Context
Chalcopyrite is a widespread mineral found in various geological settings, including hydrothermal veins, porphyry copper deposits, volcanogenic massive sulfide (VMS) deposits, and sedimentary exhalative (SEDEX) deposits. It forms under a range of temperatures and pressures.
