mineral

Unidentified translucent mineral fragment, possibly calcite

Calcite (calcium carbonate, CaCO₃), tentative identification

AI-generated identification · may be incorrect

Pale honey-yellow, translucent, vitreous to pearly luster, and prominent cleavage surfaces; calcite has Mohs hardness 3, rhombohedral crystal structure, and specific gravity about 2.71. The angular fragment’s cleavage and color are consistent with calcite, though the photograph is insufficient for certainty.

Identified August 9, 2026More mineral →

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Physical properties

Formation & geological history

Calcite commonly forms in limestone, hydrothermal veins, caves, and geodes through precipitation from carbonate-rich fluids; specimens may range from modern to hundreds of millions of years old.

Uses & applications

Used in cement, lime, construction aggregate, glass manufacture, and as a collectible or ornamental mineral. Transparent varieties may be faceted, though this piece appears specimen-grade rather than gem-grade.

Geological facts

Calcite strongly effervesces with dilute hydrochloric acid and commonly shows double refraction in clear crystals. Yellow coloration can result from iron or other trace impurities.

Field identification & locations

Test suspected calcite with a steel nail (it scratches calcite) and dilute acid; identify its characteristic rhombohedral cleavage. Common worldwide, especially in Mexico, Iceland, the United States, and China.