mineral

Blue calcite

Calcite (CaCO₃)

AI-generated identification · may be incorrect

Pale blue to gray, translucent, with a vitreous-to-pearly luster and prominent rhombohedral cleavage; Mohs hardness 3, trigonal crystal system, specific gravity about 2.7. The specimen’s blue color and cleavage are consistent with calcite, though image identification is not definitive.

Identified September 25, 2026More mineral →

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Physical properties

Formation & geological history

Forms in sedimentary settings, hydrothermal veins, and cavities as calcium-carbonate-rich fluids precipitate or limestone recrystallizes. Calcite occurs in rocks of many ages; the specimen’s age and locality cannot be determined from the image.

Uses & applications

Used in cement and lime production, construction stone, soil treatment, and as a decorative or collectible mineral; soft blue pieces are generally ornamental rather than suitable for durable jewelry.

Geological facts

Calcite effervesces in dilute acid and is readily scratched by a copper coin or steel blade; clear varieties can show strong double refraction.

Field identification & locations

Look for rhombohedral cleavage, low hardness, and acid reaction; common worldwide, including in limestone and hydrothermal deposits. Avoid harsh handling because it scratches and cleaves easily.