Pollucite
Mineral Cs(Si2Al)O6·nH2O
About it
The caesium ore of lithium pegmatites; it resembles quartz but has a greasy look and rarely shows crystal faces. Gem rough from Maine, Afghanistan, and Pakistan; Manitoba's Tanco mine holds large reserves.
- Type
- Mineral
- Group
- Silicate (tectosilicate), zeolite group
- Formula
- Cs(Si2Al)O6·nH2O
- Hardness (Mohs)
- 6.5–7
- Specific gravity
- 2.68–3.03
- Streak
- white
- Lustre
- vitreous (glassy), greasy
- Crystal system
- Isometric (cubic)
- Colours
- colourless, white, grey, pink
- Transparency
- transparent, translucent
- Cleavage and fracture
- none; conchoidal fracture
Typical values: real specimens vary. For more, see mindat.org.