Sodalite
Royal blue sodium silicate, the blue in lapis without the gold.
- Family
- Sodalite
- Formula
- Na₈Al₆Si₆O₂₄Cl₂
- Mohs
- 5.5 to 6
- System
- Cubic
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Science
Sodalite belongs to the same feldspathoid family as lazurite and forms in rocks poor in silica. Its blue is from sulphur trapped in the cage structure. Hackmanite, a sulphur-rich variety, is tenebrescent: it turns pink or violet in sunlight and fades back in the dark.
- Mineral
- Sodalite
- Formula
- Na₈Al₆Si₆O₂₄Cl₂
- Crystal system
- Cubic
- Mohs hardness
- 5.5 to 6
- Specific gravity
- 2.27 to 2.33
- Refractive index
- 1.483 to 1.487
- Lustre
- Vitreous to greasy
- Colours
- Blue, White veined
Composition
Na₈Al₆Si₆O₂₄Cl₂. Made of Sodium, Aluminium, Silicon, Oxygen, Chlorine.
Origin
- BrazilBahia
- CanadaBancroft, Ontario; Princess sodalite
- Namibia
- GreenlandIlímaussaq
- Russia
- United StatesMaine
Filled dots are primary sources
Rarity
Readily available as massive rock; transparent crystals are very rare.
- 1 Abundant
- 2 Common
- 3 Uncommon
- 4 Rare
- 5 Exceptional
Hardness
Sodalite sits at 5.5 to 6 on the Mohs scale. Glass and a knife blade are about as hard; it wears well with care.
Energy
Associations from crystal-healing tradition, recorded here as folklore. They are not medical claims.
Chakras
- Throat
- Third Eye
Element
- Air
Zodiac
- Sagittarius
Planets
- Moon
Properties
- Logic
- Truth
- Self-trust
- Calm mind
Lore
Named for its sodium in 1811 from Greenland, it became fashionable after Princess Margaret of England admired Ontario sodalite in 1901 and chose it for Marlborough House, hence 'Princess Blue'.
Its modern reputation is intellectual: the stone of reason and of saying what is true.
- HackmaniteChanges colour in UV and reverts, a reversible effect called tenebrescence.
- Not lapisLacks pyrite and is greyer; often sold as its substitute.