Sodalite
Sodalite · Semi-Precious Gemstone, Decorative Stone, and Mineral Specimen
Crystal System
Cubic (Isometric), typically found in massive, granular, or nodular habits rather than distinct crystals
Mineral Group
Silicates, specifically Tectosilicates and the Feldspathoid group
Chemical Formula
Na8Al6Si6O24Cl2
Formation Process
Igneous, formed in silica-poor alkaline igneous rocks such as nepheline syenites and associated pegmatites from a cooling magma melt
About This Crystal
The specimen is a tumbled and polished gemstone displaying a rich, vibrant royal blue color with distinct mottled patterns of white calcite veins and occasional dark inclusions. It has a vitreous to greasy luster, is opaque to translucent along thin edges, and has a smooth, rounded, teardrop-like tumbled shape.
Physical Characteristics
Deep royal blue to violet body color with white patches or veins; white streak; no true cleavage (poor dodecahedral); conchoidal to uneven fracture; specific gravity of approximately 2.15 to 2.35; brittle tenacity; displays weak orange-yellow fluorescence under ultraviolet light in some varieties
Optical Properties
Singly refractive (isotropic); refractive index ranges from approximately 1.483 to 1.487; usually lacks pleochroism due to its isometric crystal system; no significant optical phenomena like chatoyancy or asterism
Hardness & Durability
Origin Region
Notable sources include Ontario (Canada), Greenland, Russia, India, Brazil, and the USA (Bancroft area in Ontario is famous for rich blue sodalite)
Hardness & Durability
Mohs hardness of 5.5 to 6; fair toughness but vulnerable to sharp impacts due to brittleness; moderate stability; suitable for lower-impact jewelry like pendants, earrings, and rings with protective settings
Care & Maintenance
Clean with warm soapy water and a soft cloth; avoid harsh chemical cleaners, mechanical ultrasonic cleaners, and steam cleaners; store separately from harder gems like quartz or topaz to prevent scratching; protect from prolonged direct sunlight to prevent color fading
Rarity & Value
Common to uncommon; highly affordable as a tumbled stone or decorative carving; value increases for intense, uniform blue colors or rare varieties like hackmanite; widely available globally
Special Characteristics
Certain varieties of sodalite, known as hackmanite, exhibit tenebrescence (photochromism), where they temporarily change color or darken when exposed to sunlight and fade back indoors
Lore & History
First discovered in 1811 in Greenland and officially described in 1883, it became popular as an ornamental stone after extensive deposits were found in Canada. In modern crystal healing, sodalite is traditionally associated with the throat and third-eye chakras, believed to enhance logic, rational thought, truth, and emotional balance, though these are cultural and metaphysical beliefs without scientific backing