Sodalite
Mineral Na8Al6Si6O24Cl2
Also called Princess blue
About it
Royal blue masses with white veins, lighter than lapis and lacking pyrite; Bancroft, Ontario, Brazil, and Namibia. Its white streak tells it from lazurite. Hackmanite changes colour in UV and sunlight.
- Type
- Mineral
- Group
- Silicate (tectosilicate), sodalite group
- Formula
- Na8Al6Si6O24Cl2
- Hardness (Mohs)
- 5.5–6
- Specific gravity
- 2.27–2.33
- Streak
- white
- Lustre
- vitreous (glassy), greasy
- Crystal system
- Isometric (cubic)
- Colours
- royal blue, blue, white, grey, violet, pink
- Transparency
- transparent, translucent
- Cleavage and fracture
- poor dodecahedral; conchoidal to uneven fracture
- Under UV light
- often orange under longwave UV
Typical values: real specimens vary. For more, see mindat.org.