mineral

Calcite crystal cluster with matrix fragments

Calcite (CaCO₃), likely with minor iron-oxide staining and possibly associated quartz or feldspar

AI-generated identification · may be incorrect

Pale peach to brown and white, vitreous to dull luster, with blocky to scalenohedral fragments and prominent rhombohedral cleavage; calcite has Mohs hardness 3 and specific gravity about 2.71. Crystal structure is trigonal.

Identified October 13, 2026More mineral →

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Physical properties

Formation & geological history

Calcite commonly precipitates from mineral-rich groundwater or hydrothermal fluids in veins and cavities; the image alone cannot establish the specimen’s age or exact setting.

Uses & applications

Primarily a collector specimen; calcite is also used in cement, lime, aggregate, and industrial fillers, though this fragmented material is not suitable as a gemstone.

Geological facts

Calcite effervesces readily in dilute hydrochloric acid and can show double refraction in clear crystals.

Field identification & locations

Look for softness, rhombohedral cleavage, and vigorous acid reaction; calcite occurs worldwide in limestone cavities, veins, and hydrothermal deposits. The apparent fragments and lack of scale limit a more specific identification.