Rock Identifier
Tumbled sodalite (Sodalite, Na8(Al6Si6O24)Cl2, commonly occurring in nepheline-syenite rocks) — mineral
mineral

Tumbled sodalite

Sodalite, Na8(Al6Si6O24)Cl2, commonly occurring in nepheline-syenite rocks

AI-generated identification · may be incorrect

Usually deep blue to blue-gray with white calcite veining, vitreous to greasy luster, and an imperfect cleavage; Mohs hardness 5.5–6, cubic crystal system, specific gravity about 2.2–2.4. The rounded shape and shine indicate tumbling or polishing.

Identified More mineral
Explore Tumbled sodalite in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

Physical properties

Usually deep blue to blue-gray with white calcite veining, vitreous to greasy luster, and an imperfect cleavage; Mohs hardness 5.5–6, cubic crystal system, specific gravity about 2.2–2.4. The rounded shape and shine indicate tumbling or polishing.

Formation & geological history

Forms as a feldspathoid mineral in silica-poor, sodium-rich igneous rocks such as nepheline syenite, generally in alkaline intrusive complexes. Important deposits occur in Canada, Brazil, Namibia, and Russia; individual specimens may range from Precambrian to younger igneous ages.

Uses & applications

Used as an ornamental stone, beads, cabochons, carvings, and lapidary material; fine blue pieces are sometimes sold as inexpensive gemstone substitutes for lapis lazuli.

Geological facts

The specimen’s uniform blue-gray color and cloudy white patches are consistent with sodalite, though image quality prevents certain distinction from blue calcite or dyed stone. Unlike lapis lazuli, sodalite typically lacks abundant metallic-gold pyrite flecks.

Field identification & locations

Identify by its blue color, white veining, moderate hardness, and lack of strong reaction to dilute acid; a streak test should be pale blue/white. Common tumbled pieces are widely sold in metaphysical and mineral shops.