mineral

Blue calcite (probable)

Calcite — CaCO₃

AI-generated identification · may be incorrect

Pale blue-gray, translucent mineral with vitreous to pearly luster and prominent cleavage; Mohs hardness 3, trigonal crystal structure, and specific gravity about 2.71. The rough, irregular piece may also contain white calcite or minor inclusions.

Identified August 11, 2026More mineral →

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Physical properties

Formation & geological history

Forms mainly in hydrothermal veins, cavities, and sedimentary limestone environments when calcium-carbonate-rich fluids precipitate; specimens can range from ancient to geologically recent. Common sources include Mexico, Madagascar, Pakistan, and the United States.

Uses & applications

Used as a collector specimen, ornamental stone, and occasionally for decorative carvings; calcite is also important industrially in cement, lime, agriculture, and chemical production.

Geological facts

Calcite effervesces visibly with dilute hydrochloric acid and shows strong birefringence, producing doubled images through clear pieces. Color is commonly caused by trace impurities or inclusions.

Field identification & locations

Identify by its soft hardness, excellent rhombohedral cleavage, acid reaction, and lack of quartz-like glassy fracture; avoid confusing it with blue fluorite or quartz. Photograph-based identification is provisional without tests.