metamorphic
Tumbled lapis lazuli
Lazurite-bearing calcite rock; lazurite approximately Na₃Ca(Si₃Al₃)O₁₂S
AI-generated identification · may be incorrectBlue and white polished stone with minor brassy pyrite-like flecks; lazurite has Mohs hardness 5–5.5, vitreous to dull luster, and a granular, non-cleavable texture. The white areas are commonly calcite, which is softer and effervesces weakly in acid.
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Physical properties
Blue and white polished stone with minor brassy pyrite-like flecks; lazurite has Mohs hardness 5–5.5, vitreous to dull luster, and a granular, non-cleavable texture. The white areas are commonly calcite, which is softer and effervesces weakly in acid.
Formation & geological history
Formed by contact metamorphism of limestone, typically during Precambrian geological events. Major deposits occur in Afghanistan, with additional material from Chile, Russia, and Pakistan.
Uses & applications
Used for beads, cabochons, carvings, decorative objects, and historically ultramarine pigment; low-grade pieces are inexpensive ornaments.
Geological facts
True lapis lazuli is a rock rather than a single mineral, consisting mainly of lazurite plus calcite, diopside, and sometimes pyrite. Strong, even royal-blue color generally commands the highest price.
Field identification & locations
Identify it by its opaque blue color, white calcite veining, occasional metallic flecks, and polished tumbled form; dyeing and imitation are common, so a hardness or acid test can help. Typical specimens are found in metamorphosed limestone deposits.
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