Covellite
Image: <a href="//commons.wikimedia.org/wiki/User:Islam90" title="User:Islam90">Islam90</a> (CC BY-SA 4.0)
Mineral NameCovellite
Chemical FormulaCuS
Mohs Hardness1.5
Crystal Systemhexagonal
Streak Colorgrayish black
Cleavageperfect basal on {0001}
Fractureuneven
Specific Gravity4.6
Colorsindigo-blue, dark blue, purplish blue
Transparencyopaque
Type LocalityVesuvius, Italy
Mineral Groupsulfides
Usesminor ore of copper, collector
Associated Mineralspyrite, chalcopyrite, bornite, chalcocite
Rarityuncommon
Description
This microscopic image displays a field of vibrant indigo-blue covellite, showing its characteristic color and texture, interspersed with brighter, yellowish-metallic grains of pyrite. The surface exhibits scratches from polishing, typical of a thin section prepared for microscopic analysis.
Geological Context
Covellite is a secondary copper sulfide mineral that forms in the supergene enrichment zones of copper deposits, often replacing primary copper sulfides under low-temperature, acidic conditions. It is an important indicator mineral for such environments.
