Sodalite
Sodalite (IMA recognized species) · Semi-Precious Gemstone / Decorative Stone
Crystal System
Cubic (Isometric); typically found in massive or granular habits, rarely as dodecahedral crystals.
Mineral Group
Silicates; Tectosilicate (Feldspathoid group)
Chemical Formula
Na8(Al6Si6O24)Cl2
Formation Process
Igneous formation; crystallizes from alkali-rich, silica-undersaturated magmas. Also found in contact metamorphic zones.
About This Crystal
Deep royal blue color with mottled white veins or patches of calcite. This specimen is carved into a heart shape, showing a vitreous to greasy luster. It is opaque to slightly translucent at thin edges.
Physical Characteristics
Color: Royal blue to violet-blue with white streaks; Streak: White; Cleavage: Poor; Fracture: Uneven/Conchoidal; Specific Gravity: 2.27–2.33; Fluorescence: Typically strong bright orange/pink under Longwave UV due to the presence of chlorine.
Optical Properties
Refractive Index: 1.483–1.487 (Singly refractive/Isotropic); lacks pleochroism and dispersion; no play of color.
Hardness & Durability
Origin Region
Major sources include Bancroft (Ontario, Canada), Namibia, Brazil, and Russia (Kola Peninsula). Forms in silica-poor igneous rocks like nepheline syenites.
Hardness & Durability
Mohs Hardness: 5.5 to 6. Toughness is poor to fair; it is somewhat brittle and sensitive to pressure and scratches from harder stones like quartz.
Care & Maintenance
Clean with warm soapy water and a soft cloth only. Avoid ultrasonic cleaners and steam. Sensitive to acids (even mild ones). Store away from harder gemstones to prevent surface scratching.
Rarity & Value
Common; widely available and affordable. Value is determined by the intensity of the blue and the aesthetic distribution of white calcite inclusions. Rarely treated, though some inferior material may be dyed.
Special Characteristics
Known for its distinctive bright orange fluorescence under long-wave ultraviolet light. Tenabrascent varieties (Hackmanite) can change color when exposed to light.
Lore & History
Discovered in Greenland in 1811; became popular as a decorative stone after a large deposit was found in Canada during a Royal visit in 1901. Traditionally associated with the Throat and Third Eye chakras, believed to promote logic, truth, and inner peace.