mineral

Blue calcite (probable)

Calcite, CaCO₃

AI-generated identification · may be incorrect

Pale to vivid blue, cloudy and irregular with a vitreous-to-pearly luster; Mohs hardness 3, excellent rhombohedral cleavage, trigonal crystal system, and specific gravity about 2.71. The specimen may contain gray or brown matrix/inclusions.

Identified August 9, 2026More mineral →

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Physical properties

Formation & geological history

Blue calcite forms in hydrothermal veins, cavities, and carbonate-rich sedimentary environments when trace elements or inclusions produce its color. The image alone cannot establish its geological age; deposits occur in many Phanerozoic carbonate sequences.

Uses & applications

Primarily a collector specimen, ornamental stone, and lapidary material; calcite is also industrially important in cement, lime, aggregate, and chemical production. Blue material is generally too soft for durable jewelry.

Geological facts

Calcite effervesces strongly with dilute hydrochloric acid and shows perfect rhombohedral cleavage. Its blue color can overlap with aragonite, fluorite, or dyed carbonate material, so testing is recommended.

Field identification & locations

Common sources include Mexico, Madagascar, Peru, and parts of the United States. Confirm identification with a hardness test, acid reaction, cleavage, and—if necessary—specific-gravity or laboratory analysis.