mineral

Polished blue-green calcite

Calcite (calcium carbonate, CaCO₃)

AI-generated identification · may be incorrect

Typically pale blue-green to nearly colorless, translucent, with vitreous to pearly luster and prominent rhombohedral cleavage; Mohs hardness 3, specific gravity about 2.71. The rounded form is polished or tumbled, and internal fractures/cloudiness are visible.

Identified August 20, 2026More mineral →

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Physical properties

Formation & geological history

Calcite forms in limestone, hydrothermal veins, cavities, and sedimentary environments through precipitation of calcium carbonate. Its age may range from modern cave deposits to Precambrian or younger host rocks; the specimen’s exact age and locality cannot be determined from the image.

Uses & applications

Used for cement, lime, aggregate, neutralizing acidic soils, and optical/calcareous materials; attractive translucent pieces are sold as décor or inexpensive mineral specimens.

Geological facts

Calcite effervesces strongly with dilute hydrochloric acid and shows birefringence (“double refraction”) in clear pieces. Blue-green coloration can result from trace metals or inclusions, so visual identification alone is not definitive.

Field identification & locations

Test a hidden area with vinegar or dilute HCl, observe rhombohedral cleavage, and distinguish it from fluorite by its much lower hardness and acid reaction. Common localities include Mexico, the United States, Iceland, China, and Morocco.