COVELLITE

 

Covellite is an attractive, deep metallic blue mineral having the formula CuS - copper sulfide.  It's principally a secondary sulfide mineral, formed by the breakdown of pre-existing copper-bearing sulfides, but also occurs in a massive or crystalline form as a primary mineral.  Covellite has a metallic luster, an intensely deep blue or purplish blue color, a dark gray streak, and is quite soft (H = 1.5 to 2).  Well-formed crystals are hexagonal plates with a somewhat micaceous appearance.

 


 

Covellite (1.9 cm across along the base) from the Leonard Mine at Butte, Montana, USA.  Butte covellite occurs in copper sulfide-rich hydrothermal veins (62-66 million years, latest Cretaceous to Early Paleocene) that intrude the Butte Quartz Monzonite (mid-Campanian Stage, late Late Cretaceous, 76 million years).

 


 

Covellite (1.4 cm across) from the Leonard Mine at Butte, Montana, USA.  Butte covellite occurs in copper sulfide-rich hydrothermal veins (62-66 million years, latest Cretaceous to Early Paleocene) that intrude the Butte Quartz Monzonite (mid-Campanian Stage, late Late Cretaceous, 76 million years).

 


 

Covellite-pyrite hydrothermal vein (4.1 cm across at its widest) from the Butte Mining District, southwestern Montana, USA (same geology as specimens shown above).

 


 

Photo gallery of covellite

 


 

Home page