Covellite and Pyrite
Image: <a href="//commons.wikimedia.org/wiki/User:Islam90" title="User:Islam90">Islam90</a> (CC BY-SA 4.0)
Mineral NameCovellite and Pyrite
Chemical FormulaCuS (Covellite), FeS2 (Pyrite)
Mohs HardnessCovellite: 1.5-2, Pyrite: 6-6.5
Streak ColorCovellite: Grayish black to lead gray; Pyrite: Greenish black to brownish black
CleavageCovellite: Perfect on {0001}; Pyrite: Indistinct on {001}
FractureCovellite: Uneven; Pyrite: Conchoidal to uneven
Specific GravityCovellite: 4.6-4.76, Pyrite: 4.95-5.10
Colorsindigo blue, dark blue, purplish blue, pale brass-yellow
Transparencyopaque
Type LocalityWorldwide, common in copper sulfide deposits
Mineral GroupSulfides
Usesminor copper ore, minor sulfur ore, collector's mineral
Associated Mineralschalcocite, bornite, chalcopyrite, enargite, sphalerite, galena, quartz
Description
The image displays a microscopic view of a mineral thin section containing covellite and pyrite. The upper panel shows the minerals under normal light with bluish-green and white hues, while the lower panel shows the same area under polarized light, revealing pinkish-brown and white interference colors and textures.
Geological Context
This association is typical of copper sulfide deposits. Pyrite often forms as a primary sulfide, and covellite commonly develops as a secondary mineral during supergene enrichment, replacing earlier copper sulfides or pyrite.
