Sodalite
Sodalite · Semi-Precious Gemstone and Ornamental Stone
Crystal System
Cubic (Isometric), usually occurs in massive, granular, or nodular habits rather than well-formed crystals
Mineral Group
Silicates, specifically Tectosilicates (Feldspathoid group)
Chemical Formula
Na8Al6Si6O24Cl2
Formation Process
Igneous formation, typically crystallizing in silica-poor igneous rocks such as nepheline syenites and associated pegmatites, often from sodium-rich magmas
About This Crystal
The specimen is a beaded stretch bracelet featuring round, polished spherical beads. The beads display a rich royal blue to grayish-blue body color, heavily mottled with characteristic white calcite veins and patches, as well as occasional dark inclusions, giving them a patchy, mottled appearance with a vitreous to greasy luster and opaque transparency
Physical Characteristics
Color ranges from royal blue, blue-gray, to violet, with white streaks from calcite impurities. Streak is white. Cleavage is poor in six directions (dodecahedral). Fracture is uneven to conchoidal. Specific gravity is approximately 2.14 to 2.40. Tenacity is brittle. May show weak orange to yellow fluorescence under longwave UV light due to impurities
Optical Properties
Isotropic (singly refractive) with a refractive index of approximately 1.483 to 1.487. Generally lacks pleochroism due to its isometric crystal system, but can occasionally show subtle optical anomalies in strained areas
Hardness & Durability
Origin Region
Notable sources include Brazil, Canada (Ontario), India, Namibia, Russia, and the United States (Bancroft area in Ontario is famous for rich blue sodalite)
Hardness & Durability
Mohs hardness of 5.5 to 6, making it moderately soft and easily scratched by harder stones like quartz. Toughness is fair to poor due to its brittle nature and poor cleavage. Suitable for low-impact jewelry like earrings and necklaces, or bracelets with careful wear
Care & Maintenance
Clean with warm, soapy water and a soft cloth. Avoid ultrasonic cleaners, steam cleaners, and harsh chemical detergents or acids. Store separately from harder gemstones to prevent scratching, and protect from prolonged direct sunlight to prevent potential color fading
Rarity & Value
Common; sodalite is widely distributed globally. Value is generally low to moderate, primarily determined by color saturation, uniformity, and the contrast of white calcite inclusions. Typically affordable as tumbled stones, beads, and cabochons. Treatments are rare, though sometimes stabilized with resin for bead cutting
Special Characteristics
Notable for its distinctive mottled blue and white appearance, created by a matrix of sodalite and white calcite. Some varieties (like hackmanite) exhibit tenebrescence (color change upon UV exposure), though standard sodalite does not typically show this strongly
Lore & History
Discovered in 1811 in Greenland, sodalite was named for its high sodium content. It gained popularity as an ornamental stone after vast deposits were found in Ontario in the 19th century. In crystal healing, it is traditionally associated with the throat and third-eye chakras, believed to promote rational thought, objectivity, truth, and emotional balance, though these remain traditional beliefs without scientific backing