mineral

Polished white calcite sphere (identification tentative)

Calcite, CaCO₃

AI-generated identification · may be incorrect

Milky white to translucent with a vitreous-to-pearly luster; calcite has Mohs hardness 3, trigonal crystal structure, and prominent rhombohedral cleavage. The polished spherical shape prevents reliable identification from appearance alone; similar-looking materials include quartz and man-made glass.

Identified October 3, 2026More mineral →

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Physical properties

Formation & geological history

If calcite, it formed by precipitation from mineral-rich water or in limestone and marble; such deposits span many geological ages. The sphere has been cut and polished by people.

Uses & applications

Used as a decorative or collector’s sphere; calcite is also used in cement, lime, and agricultural products.

Geological facts

Calcite fizzes in dilute acid, a useful distinguishing test; avoid this test on a polished collectible unless a hidden spot is acceptable.

Field identification & locations

Check hardness and acid reaction, or have it tested; common calcite occurs worldwide in limestone, caves, and hydrothermal veins. Visual identification from this image is uncertain.