mineral

Blue calcite (probable)

Calcite, CaCO₃

AI-generated identification · may be incorrect

Pale blue, translucent to opaque, with a dull-to-glassy luster and prominent rhombohedral cleavage; Mohs hardness 3 and specific gravity about 2.71. The broken surfaces and color fit blue calcite, though the photograph cannot exclude pale blue aragonite or dyed material.

Identified August 31, 2026More mineral →

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Physical properties

Formation & geological history

Calcite forms in hydrothermal veins, limestone cavities, and sedimentary environments; blue coloration commonly reflects trace impurities or inclusions. Calcite deposits range from ancient to modern, and this specimen cannot be dated visually.

Uses & applications

Used for calcium carbonate, cement, lime, construction aggregate, and industrial fillers; attractive blue pieces are sold as decorative or collecting specimens rather than jewelry because they scratch easily.

Geological facts

Calcite effervesces vigorously with dilute hydrochloric acid or vinegar (especially when powdered), and it shows rhombohedral cleavage rather than cubic cleavage. It is common worldwide.

Field identification & locations

Likely identification is based on the pale blue color and blocky cleavage. Test a hidden edge with vinegar, check hardness against a copper coin, and look for cleavage planes; around 50.2°N, 15.5°E, sedimentary carbonate rocks and calcite veins are regionally plausible.