Sodalite

Physical Properties

Hardness: 5.5-6 on Mohs scale; Color: typically rich royal blue but can be gray, green, or pink; Luster: Vitreous to greasy; Crystal structure: Isometric; Cleavage: Poor/indistinct; Specific gravity: 2.27-2.33.

Formation & Geological History

Formed in sodium-rich igneous rocks (nepheline syenites and phonolites) and some contact metamorphic rocks. It develops in silica-undersaturated environments. Common in Precambrian to Cenozoic formations.

Uses & Applications

Used primarily in jewelry, as decorative gemstones (spheres, carvings), and occasionally in architecture as ornamental stone for countertops or tiles. Low hardness limits its use in high-wear jewelry like rings.

Geological Facts

Sodalite was first discovered in Greenland in 1811 but became popular in the 1890s after vast deposits were found in Ontario, Canada, during a royal visit. It is often confused with Lapis Lazuli but lacks the characteristic gold-colored pyrite specks.

Field Identification & Locations

Identified by its deep blue color and white streaks of calcite. Collectors often look for the 'Orange' variety (Hackmanite) which shows reversible photochromism. Best found in syenite complexes like the Bancroft area in Ontario or the Kola Peninsula in Russia.

Identified on: 4/29/2026

Mode: Standard