Sodalite
Sodalite · Semi-Precious Gemstone and Mineral Specimen
Crystal System
Cubic (Isometric), typically massive or in dodecahedral crystals
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
Na8Al6Si6O24Cl2
Formation Process
Igneous, typically crystallizing in silica-poor alkaline igneous rocks such as nepheline syenites and pegmatites at moderate to high temperatures
About This Crystal
This specimen is a raw, deep royal-blue chunk featuring characteristic white and greyish calcite veins and mottled inclusions. It has an opaque to translucent appearance with a vitreous to greasy luster, showing uneven fracture surfaces typical of massive sodalite.
Physical Characteristics
Color is rich royal blue mottled with white veins; streak is white; cleavage is poor in six directions; fracture is conchoidal to uneven; specific gravity is approximately 2.27-2.33; tenacity is brittle; may exhibit a faint orange-yellow fluorescence under longwave UV light
Optical Properties
Refractive index is around 1.483-1.487; singly refractive (isotropic); usually non-pleochroic due to its isometric crystal system
Hardness & Durability
Origin Region
Bancroft, Ontario, Canada; Langesundsfjord, Norway; Bahia, Brazil; Namibia; USA (Montana, Maine)
Hardness & Durability
Mohs hardness of 5.5 to 6; moderate durability; brittle with poor cleavage, making it susceptible to hard blows; suitable for protected jewelry settings like pendants and earrings
Care & Maintenance
Clean with warm soapy water and a soft cloth; avoid harsh chemicals, ultrasonic cleaners, and steam cleaners; store separately from harder stones to prevent scratching
Rarity & Value
Common; inexpensive ornamental and lapidary stone; value is determined by color saturation, lack of undesirable inclusions, and carving potential, with small raw specimens being very affordable
Special Characteristics
Certain varieties like hackmanite exhibit tenebrescence (color change when exposed to sunlight and back to white in the dark); this specimen shows classic mottled blue and white veining patterns
Lore & History
Discovered in 1811 in Greenland, sodalite gained popularity as an ornamental stone after extensive deposits were found in Ontario, Canada, in 1891 (earning it the nickname Princess Blue). In metaphysical practices, it is associated with the throat and third-eye chakras, believed to enhance logic, rational thought, intuition, and emotional balance (traditional beliefs, not scientific claims)