Dioptase
Mineral CuSiO3·H2O
About it
Intense emerald-green rhombohedral crystals, far softer than emerald, often on white calcite; Tsumeb, Namibia, Altyn-Tyube, Kazakhstan, and the Congo are classic.
- Type
- Mineral
- Group
- Silicate (cyclosilicate), dioptase group
- Formula
- CuSiO3·H2O
- Hardness (Mohs)
- 5
- Specific gravity
- 3.28–3.35
- Streak
- pale green
- Lustre
- vitreous (glassy)
- Crystal system
- Trigonal
- Colours
- emerald green, blue-green
- Transparency
- transparent, translucent
- Cleavage and fracture
- perfect rhombohedral
Typical values: real specimens vary. For more, see mindat.org.