Rainbow moonstone
Variety (Ca,Na)(Si,Al)4O8
Also called White labradorite
About it
Nearly colourless labradorite with a blue or rainbow sheen, sold as moonstone though it is a plagioclase, not orthoclase. Most comes from India and Madagascar; small dark inclusions are common.
- Type
- Variety
- Group
- Labradorite variety (feldspar)
- Formula
- (Ca,Na)(Si,Al)4O8
- Hardness (Mohs)
- 6–6.5
- Specific gravity
- 2.68–2.72
- Streak
- white
- Lustre
- vitreous (glassy)
- Crystal system
- Triclinic
- Colours
- white, colourless, with a blue or multicoloured sheen
- Transparency
- transparent, translucent
- Cleavage and fracture
- perfect in one direction, good in another at about 86°
Typical values: real specimens vary. For more, see mindat.org.