Cryolite
Mineral Na3AlF6
Also called Ice stone
About it
Snow-white to colourless masses that almost vanish in water because they bend light so nearly as water does. Mined at Ivittuut (Ivigtut), Greenland, for aluminium smelting until 1987.
- Type
- Mineral
- Group
- Halide, cryolite group
- Formula
- Na3AlF6
- Hardness (Mohs)
- 2.5–3
- Specific gravity
- 2.95–3
- Streak
- white
- Lustre
- vitreous (glassy), greasy
- Crystal system
- Monoclinic
- Colours
- colourless, white, brownish, reddish
- Transparency
- transparent, translucent
- Cleavage and fracture
- none; pseudocubic parting, uneven fracture
Typical values: real specimens vary. For more, see mindat.org.