mineral

Raw calcite specimen

Calcite, calcium carbonate (CaCO₃)

AI-generated identification · may be incorrect

Pale honey-yellow, translucent to transparent, with a vitreous-to-pearly luster and prominent rhombohedral cleavage; Mohs hardness 3, trigonal crystal structure, and specific gravity about 2.71. The apparent blocky faces and milky internal zones are consistent with calcite, though image-only identification is not defin…

Identified August 8, 2026More mineral →

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Physical properties

Formation & geological history

Calcite forms in sedimentary limestones, hydrothermal veins, caves, and metamorphic marbles through precipitation or recrystallization. It occurs from ancient Precambrian deposits to modern cave and vein environments.

Uses & applications

Used to make cement and lime, as a soil conditioner, construction aggregate, optical material, and mineral specimens; clear varieties may be collected but are rarely gem-quality.

Geological facts

Calcite effervesces strongly with dilute hydrochloric acid and commonly shows birefringence, producing doubled images through clear pieces.

Field identification & locations

Common worldwide, especially in limestone regions, hydrothermal veins, Mexico, Iceland, and the United States. Confirm with a hardness test, rhombohedral cleavage, and acid reaction; avoid scratching valuable specimens.