Sodalite
Sodalite (from the Sodalite group) · Semi-Precious Gemstone / Mineral Specimen / Decorative Stone
Crystal System
Cubic (Isometric); usually occurs in massive or granular habits; rarely as dodecahedral crystals.
Mineral Group
Silicates; Tectosilicate (Feldspathoid group)
Chemical Formula
Na8(Al6Si6O24)Cl2
Formation Process
Igneous; forms in alkaline igneous rocks like nepheline syenites and phonolites, or in metasomatized calcareous rocks.
About This Crystal
Opaque to translucent material with a deep royal blue base, often mottled with white veins or patches of calcite. It has a vitreous to greasy luster when polished.
Physical Characteristics
Color: Royal blue to violet-blue with white streaks; Streak: White; Cleavage: Poor; Fracture: Conchoidal to uneven; Specific Gravity: 2.27–2.33; Fluorescence: Strong bright orange to red under LWUV.
Optical Properties
Refractive Index: 1.48 (Isotropic); Birefringence: None; Optical phenomena: Lacks the metallic golden inclusions of Lapis Lazuli.
Hardness & Durability
Origin Region
Notable sources include Bancroft (Ontario, Canada), Namibia, Brazil, Afghanistan, and Greenland. It is typically found in silica-poor igneous rocks.
Hardness & Durability
Mohs Hardness: 5.5 to 6. Toughness is fair; it is somewhat brittle and sensitive to pressure and scratches.
Care & Maintenance
Clean with warm soapy water only; avoid ultrasonic cleaners and steam. Sensitive to acids and sudden temperature changes. Store away from harder gems like quartz.
Rarity & Value
Common and affordable. Value is determined by color intensity and the absence of distracting white/grey patches. Rarely treated, though some may be dyed.
Special Characteristics
Hackmanite variety exhibits tenebrescence (color change when exposed to light). Standard sodalite exhibits strong orange fluorescence under ultraviolet light.
Lore & History
Discovered in Greenland in 1811; became popular as a decorative stone in Canada after the 1901 Royal visit. Historically called 'The Poet's Stone' and associated with the Throat and Third Eye chakras for communication.