Sodalite
Sodalite (Chloric Sodium Aluminum Silicate) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Cubic (Isometric); commonly occurs in massive or granular habits, rarely as dodecahedral crystals.
Mineral Group
Silicates; Tectosilicates (Sodalite Group)
Chemical Formula
Na8(Al6Si6O24)Cl2
Formation Process
Igneous; forms in silica-poor environments like nepheline syenites, phonolites, and associated pegmatites.
About This Crystal
A deep royal blue mineral often mottled with white streaks or patches of calcite. It has a vitreous to greasy luster and is typically opaque to translucent.
Physical Characteristics
Color: Royal blue to violet-blue with white veining. Streak: White. Cleavage: Poor (6 directions). Fracture: Uneven to conchoidal. Specific Gravity: 2.27–2.33. Fluorescence: Often bright orange-red or pink under Longwave UV.
Optical Properties
Refractive Index: 1.483–1.487 (Single refraction). Birefringence: None. Luster: Vitreous to greasy.
Hardness & Durability
Origin Region
Brazil (Bahia), Canada (Bancroft), Namibia, Greenland, and Russia (Kola Peninsula).
Hardness & Durability
Mohs Hardness: 5.5 to 6. Brittle toughness. Reasonable for jewelry but sensitive to scratches compared to quartz.
Care & Maintenance
Clean with warm soapy water and a soft cloth; avoid ultrasonic cleaners, steam, and harsh chemicals (acids). Store separately to prevent scratching.
Rarity & Value
Common and affordable. Value is determined by color intensity and the presence/absence of white calcite veining. Generally untreated.
Special Characteristics
Often exhibits strong orange fluorescence. Hackmanite (a variety) displays tenebrescence (color change when exposed to light).
Lore & History
Discovered in Greenland in 1811; became popular as an ornamental stone in Canada after a royal visit by Princess Margaret. Traditionally associated with the Throat and Third Eye chakras, believed to promote logic, truth, and inner peace.