mineral

Banded calcite (tumbled)

Calcite, CaCO₃

AI-generated identification · may be incorrect

Cream, gray, and bluish-green planar bands; typically vitreous to pearly luster and rhombohedral cleavage. Hardness 3 Mohs, specific gravity about 2.71; the rounded shape indicates tumbling or polishing.

Identified August 30, 2026More mineral →

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Physical properties

Formation & geological history

Formed by precipitation from carbonate-rich groundwater or hydrothermal fluids, commonly in veins, caves, and sedimentary cavities. The visible bands reflect changing impurities and growth conditions; precise age and locality cannot be determined from the image.

Uses & applications

Used as a decorative and educational specimen; calcite is also important in cement, lime, aggregate, and chemical industries. Common tumbled pieces generally have modest collector value.

Geological facts

Calcite effervesces readily with dilute hydrochloric acid and shows strong birefringence under polarized light. Its perfect rhombohedral cleavage distinguishes it from similarly banded quartz materials.

Field identification & locations

Commonly found in limestone regions, hydrothermal veins, and cave deposits worldwide, including Mexico, the United States, and Europe. Confirm with an acid test, hardness test, and cleavage rather than appearance alone.