mineral

Blue calcite

Calcite (CaCO₃), blue variety

AI-generated identification · may be incorrect

Usually pale blue to blue-gray, translucent to opaque, with a vitreous-to-pearly luster and prominent rhombohedral cleavage; Mohs hardness 3, specific gravity about 2.71. The blocky shape and whitish veining are consistent with calcite, though image-only identification is approximate.

Identified September 11, 2026More mineral →

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Physical properties

Formation & geological history

Forms when calcium-rich groundwater or hydrothermal fluids precipitate calcite in veins, cavities, and sedimentary environments; individual specimens may range from recent deposits to Paleozoic or younger host rocks.

Uses & applications

Commonly sold as a decorative and lapidary stone; calcite is industrially important in limestone, cement, agricultural lime, glassmaking, and chemical manufacture, but blue material is generally too soft for durable jewelry.

Geological facts

Calcite effervesces vigorously in dilute hydrochloric acid and shows strong birefringence when transparent. Blue color commonly results from trace impurities or inclusions, and it can fade or scratch easily.

Field identification & locations

Look for rhombohedral cleavage, low hardness, and acid reaction; it can be distinguished from blue fluorite by its cleavage and from blue quartz by its softness. Common sources include Mexico, Madagascar, Brazil, and the United States.