Spectrolite
Variety (Ca,Na)(Si,Al)4O8
About it
Dark labradorite from Ylämaa in southeast Finland that flashes the full spectrum, not just blue. The name was coined for the Finnish material, though similar stones now come from Madagascar.
- 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), pearly
- Crystal system
- Triclinic
- Colours
- dark grey to black with blue, green, gold, orange, and red flashes
- Transparency
- translucent, opaque
- Cleavage and fracture
- perfect in one direction, good in another at about 86°
Typical values: real specimens vary. For more, see mindat.org.