Plancheite
Mineral Cu8Si8O22(OH)4·H2O
About it
Pale to deep blue fibrous crusts and silky sprays in oxidized copper deposits of the Congo and Namibia; harder than chrysocolla and shattuckite.
- Type
- Mineral
- Group
- Silicate (inosilicate)
- Formula
- Cu8Si8O22(OH)4·H2O
- Hardness (Mohs)
- 5.5–6
- Specific gravity
- 3.65–3.8
- Lustre
- silky
- Crystal system
- Orthorhombic
- Colours
- pale to deep blue, greenish blue
- Transparency
- transparent, translucent
- Cleavage and fracture
- none observed; splintery fracture
Typical values: real specimens vary. For more, see mindat.org.