mineral

Likely calcite fragment

Calcite (calcium carbonate, CaCO₃)

AI-generated identification · may be incorrect

Pale cream to honey-colored, translucent, with a vitreous to pearly luster and prominent rhombohedral cleavage; Mohs hardness 3, specific gravity about 2.71. The rough surface and lighting limit certainty; it may also be a pale feldspar or quartz fragment.

Identified August 27, 2026More mineral →

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Physical properties

Formation & geological history

Calcite commonly forms in sedimentary limestones, hydrothermal veins, cavities, and metamorphic marbles, precipitating from calcium-rich fluids over a wide range of geological ages. A dilute acid test should produce vigorous effervescence if it is calcite.

Uses & applications

Used in cement, lime, agricultural soil treatment, fillers, and optical/cal收藏lecting specimens; this small rough piece has little commercial value.

Geological facts

Calcite is highly variable in crystal habit and commonly fluoresces under ultraviolet light. Its rhombohedral cleavage and acid reaction distinguish it from quartz.

Field identification & locations

Look for cleavage surfaces meeting at non-90° angles and test carefully with vinegar or dilute hydrochloric acid; avoid damaging valuable specimens. Common worldwide, especially in limestone regions and hydrothermal deposits.