mineral

Yellow calcite crystal

Calcite (CaCO₃), likely honey/yellow calcite

AI-generated identification · may be incorrect

Typically Mohs hardness 3, vitreous to pearly luster, pale yellow color, rhombohedral crystal structure and perfect rhombohedral cleavage; specific gravity about 2.71. The specimen appears translucent, irregularly cleaved, and partly weathered or polished.

Identified September 5, 2026More mineral →

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Physical properties

Formation & geological history

Forms when calcium-rich groundwater precipitates in cavities, veins, limestones, and hydrothermal deposits; yellow coloration commonly results from trace iron or organic impurities. Calcite occurs from Precambrian through modern geological settings.

Uses & applications

Used to manufacture cement, lime, aggregate, and industrial calcium products; clear crystals are collectible, though this small specimen has limited commercial value.

Geological facts

Calcite effervesces vigorously with dilute hydrochloric acid or household vinegar, though vinegar reacts more slowly. Its rhombohedral cleavage distinguishes it from similarly colored quartz, which is much harder and lacks cleavage.

Field identification & locations

Common worldwide in limestone, marble, caves, and mineral veins, especially Mexico, the United States, Iceland, and China. Test carefully with a steel nail and dilute acid; the surrounding gray material appears to be concrete or stone, not part of the crystal.