Cornetite
Mineral Cu3(PO4)(OH)3
About it
Small, intensely peacock-blue crystals on goethite in oxidized copper ore, mostly from the Katanga copper belt in the Congo. Named for Belgian geologist Jules Cornet.
- Type
- Mineral
- Group
- Phosphate
- Formula
- Cu3(PO4)(OH)3
- Hardness (Mohs)
- 4.5
- Specific gravity
- 4–4.2
- Streak
- blue
- Lustre
- vitreous (glassy)
- Crystal system
- Orthorhombic
- Colours
- peacock blue, greenish blue
- Transparency
- translucent
- Cleavage and fracture
- none; conchoidal to uneven fracture
Typical values: real specimens vary. For more, see mindat.org.