Carrollite
Mineral CuCo2S4
About it
Bright steel grey octahedrons with sharp faces, sometimes in spinel twins. Named for Carroll County, Maryland; the finest crystals come from Kamoya and Kambove in the Democratic Republic of the Congo.
- Type
- Mineral
- Group
- Sulfide, linnaeite group
- Formula
- CuCo2S4
- Hardness (Mohs)
- 4.5–5.5
- Specific gravity
- 4.5–5
- Streak
- dark grey
- Lustre
- metallic
- Crystal system
- Isometric (cubic)
- Colours
- steel grey, tin white, copper-red to violet tarnish
- Transparency
- opaque
- Cleavage and fracture
- imperfect cubic; conchoidal to uneven fracture
Typical values: real specimens vary. For more, see mindat.org.