mineral

Blue calcite

Calcite (CaCO₃), likely blue calcite with white carbonate matrix

AI-generated identification · may be incorrect

Typically pale blue to gray-blue, translucent to opaque, with vitreous to pearly luster and rhombohedral cleavage; Mohs hardness 3 and specific gravity about 2.71. The blocky shape and abundant cleavage surfaces are consistent with calcite.

Identified August 17, 2026More mineral →

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Physical properties

Formation & geological history

Forms when calcium-rich fluids precipitate carbonate in caves, veins, hydrothermal settings, or sedimentary rocks; specimens commonly formed during relatively recent to ancient geologic episodes rather than a single definable age.

Uses & applications

Used as a decorative and lapidary stone, ornamental carving material, and collector mineral; calcite is also important industrially in cement, lime, aggregate, and chemical production.

Geological facts

Calcite effervesces strongly with dilute hydrochloric acid or vinegar, though vinegar may react slowly. It commonly shows excellent rhombohedral cleavage and can display double refraction through clear areas.

Field identification & locations

Common sources include Mexico, Madagascar, Brazil, and the United States. Confirm with a copper coin or knife (calcite scratches easily) and an acid test; avoid confusing it with harder blue fluorite or quartz.