mineral

Blue calcite

Calcite (CaCO₃), blue variety

AI-generated identification · may be incorrect

Pale blue to whitish, translucent to opaque, with a vitreous to pearly luster and prominent rhombohedral cleavage; Mohs hardness 3, usually granular or crystalline. It commonly effervesces strongly in dilute hydrochloric acid and has specific gravity around 2.71.

Identified August 15, 2026More mineral →

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Physical properties

Formation & geological history

Forms mainly in sedimentary carbonate environments, hydrothermal veins, and cavities where calcium-rich fluids precipitate calcite; specimens may range from recent deposits to ancient sedimentary rocks. The blue color is typically caused by trace impurities or structural defects.

Uses & applications

Used primarily as a collector mineral, ornamental stone, and occasional carving material; its softness limits jewelry durability and industrial use compared with ordinary calcite limestone.

Geological facts

Blue calcite is often confused with celestite or blue aragonite, but calcite has rhombohedral cleavage and reacts readily with acid.

Field identification & locations

Commonly found in Mexico, Madagascar, South Africa, Brazil, and the United States. Identify it by its pale blue color, soft scratchability, cleavage, and acid reaction; avoid prolonged soaking because it can etch or dissolve.