Rhodizite
Mineral (K,Cs)Al4Be4(B,Be)12O28
About it
Small, very hard, glassy dodecahedrons and tetrahedral crystals in lithium-rich pegmatites. Madagascar is the main source, where much of it is londonite, a caesium-rich partner that looks the same.
- Type
- Mineral
- Group
- Borate
- Formula
- (K,Cs)Al4Be4(B,Be)12O28
- Hardness (Mohs)
- 8–8.5
- Specific gravity
- 3.44
- Streak
- white
- Lustre
- vitreous (glassy), adamantine (diamond-like)
- Crystal system
- Isometric (cubic)
- Colours
- colourless, white, yellow, greenish yellow
- Transparency
- transparent, translucent
- Cleavage and fracture
- indistinct; conchoidal fracture
Typical values: real specimens vary. For more, see mindat.org.