Rock Identifier
Polished blue banded stone, likely sodalite (Sodalite, Na₈(Al₆Si₆O₂₄)Cl₂; possibly blue calcite or dyed agate) — mineral
mineral

Polished blue banded stone, likely sodalite

Sodalite, Na₈(Al₆Si₆O₂₄)Cl₂; possibly blue calcite or dyed agate

AI-generated identification · may be incorrect

A small polished cabochon with deep blue and pale gray-white horizontal bands, vitreous to waxy luster, and no visible crystal faces. Sodalite has Mohs hardness 5.5–6, cubic structure, white streak, and commonly shows white calcite veining; the image is insufficient for definitive identification.

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Physical properties

A small polished cabochon with deep blue and pale gray-white horizontal bands, vitreous to waxy luster, and no visible crystal faces. Sodalite has Mohs hardness 5.5–6, cubic structure, white streak, and commonly shows white calcite veining; the image is insufficient for definitive identification.

Formation & geological history

Natural sodalite forms in silica-poor, alkaline igneous rocks such as nepheline syenite, generally during Precambrian to younger intrusive activity. The specimen has been cut and polished, obscuring its original texture.

Uses & applications

Used for cabochons, beads, carvings, ornamental stone, and collectors’ specimens; not generally used as a building material.

Geological facts

Strong blue color with contrasting white banding is characteristic of sodalite-group material, while uniform parallel bands could indicate dyed agate or another treated stone.

Field identification & locations

Common sources include Canada, Brazil, Greenland, Russia, and Namibia. Check with a loupe for calcite veining, test hardness carefully, and use streak, specific gravity, or Raman/XRF testing for confirmation.