mineral

Tumbled dark-blue stone, likely sodalite

Sodalite, Na₈(Al₆Si₆O₂₄)Cl₂ (tentative)

AI-generated identification · may be incorrect

Hardness 5.5–6 Mohs; deep navy-blue color with faint pale veining, vitreous to waxy luster, and massive rather than visible crystal structure. The rounded shape indicates mechanical tumbling and polishing.

Identified August 20, 2026More mineral →

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Physical properties

Formation & geological history

Sodalite forms in silica-poor, alkaline igneous rocks such as nepheline syenite, commonly during Precambrian to younger alkaline-magmatic activity. The photograph alone cannot exclude dyed quartzite, blue calcite, or another dark-blue tumbled stone.

Uses & applications

Used as an ornamental and lapidary material for cabochons, beads, carvings, and polished stones; rarely used industrially.

Geological facts

Sodalite is commonly confused with lapis lazuli, but lapis usually contains visible golden pyrite flecks and more abundant white calcite. A strong blue streak or dye bleeding under solvent would suggest an imitation or treated material.

Field identification & locations

Common sources include Canada, Brazil, Namibia, and Russia. Field identification requires hardness testing, streak, specific gravity, and examination for natural white veining; visual identification here is low-confidence.