Covellite
Mineral CuS
Also called Covelline and Indigo copper
About it
Indigo-blue plates that look purple when wet and peel into thin flexible sheets. Butte, Montana, and the Calabona mine in Sardinia produced the best hexagonal plates.
- Type
- Mineral
- Group
- Sulfide, covellite group
- Formula
- CuS
- Hardness (Mohs)
- 1.5–2
- Specific gravity
- 4.6–4.76
- Streak
- lead grey to black
- Lustre
- submetallic, resinous
- Crystal system
- Hexagonal
- Colours
- indigo blue, iridescent purple, brassy tarnish
- Transparency
- opaque
- Cleavage and fracture
- perfect basal, flexible thin plates
Typical values: real specimens vary. For more, see mindat.org.