mineral

Blue calcite

Calcite (CaCO₃)

AI-generated identification · may be incorrect

Typically pale blue to gray-blue with vitreous to pearly luster, prominent rhombohedral cleavage, and translucent to opaque appearance; Mohs hardness 3, trigonal crystal structure, specific gravity about 2.71.

Identified August 16, 2026More mineral →

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Physical properties

Formation & geological history

Forms mainly in sedimentary carbonate rocks, hydrothermal veins, and cavities from calcium-rich fluids; specimens commonly formed during relatively young to ancient diagenetic or hydrothermal processes.

Uses & applications

Used as a collectible and decorative mineral, ornamental carving stone, and occasionally as a source of lime; its softness limits jewelry use.

Geological facts

Calcite effervesces strongly with dilute hydrochloric acid and can show double refraction through clear areas. The blue color commonly results from trace impurities or structural defects.

Field identification & locations

Identify by its blue color, excellent rhombohedral cleavage, low hardness, and acid reaction; common sources include Mexico, Madagascar, Pakistan, and the United States.