Petalite
Mineral LiAlSi4O10
Also called Castorite
About it
A lithium ore of pegmatites, in glassy masses with one perfect cleavage and lighter than feldspar. Lithium was discovered in petalite from Utö, Sweden; clear gem crystals come from Brazil and Namibia.
- Type
- Mineral
- Group
- Silicate (phyllosilicate), petalite group
- Formula
- LiAlSi4O10
- Hardness (Mohs)
- 6–6.5
- Specific gravity
- 2.39–2.46
- Streak
- white
- Lustre
- vitreous (glassy), pearly
- Crystal system
- Monoclinic
- Colours
- colourless, white, grey, pink, yellow
- Transparency
- transparent, translucent
- Cleavage and fracture
- perfect in one direction; conchoidal fracture
Typical values: real specimens vary. For more, see mindat.org.