mineral
Polished sodalite heart
Sodalite, Na₈(Al₆Si₆O₂₄)Cl₂, commonly intergrown with white calcite
AI-generated identification · may be incorrectTypically deep royal-blue to gray-blue with white calcite veining or patches; vitreous to greasy luster, granular massive texture, Mohs hardness 5.5–6, poor cleavage, and specific gravity about 2.2–2.4. This specimen is cut and polished into a heart.
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Physical properties
Typically deep royal-blue to gray-blue with white calcite veining or patches; vitreous to greasy luster, granular massive texture, Mohs hardness 5.5–6, poor cleavage, and specific gravity about 2.2–2.4. This specimen is cut and polished into a heart.
Formation & geological history
Forms in silica-poor, sodium-rich igneous rocks—especially nepheline syenites and related alkaline intrusions—through late magmatic crystallization. Important deposits occur in Canada, Brazil, Namibia, and Russia; ages vary by locality, commonly Precambrian to younger.
Uses & applications
Used as a decorative carving stone, ornamental tile, beads, cabochons, and inexpensive jewelry; its vivid blue color makes it popular with collectors.
Geological facts
Sodalite can resemble lapis lazuli, but genuine sodalite commonly lacks abundant metallic pyrite flecks. It may fluoresce orange under long-wave ultraviolet light.
Field identification & locations
Identify by its blue color, white calcite mottling, moderate hardness, and lack of pyrite; it is generally softer and less dense than lapis lazuli. Common sources include Bancroft, Ontario, and Bahia, Brazil.
