mineral

Likely calcite fragment

Calcite (CaCO₃), possibly limestone or marble

AI-generated identification · may be incorrect

White, opaque to translucent fragment with a vitreous-to-pearly luster and prominent cleavage; Mohs hardness 3, rhombohedral crystal structure, specific gravity about 2.71. The image is insufficient to distinguish crystalline calcite from a calcitic rock confidently.

Identified August 14, 2026More mineral →

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Physical properties

Formation & geological history

Calcite commonly precipitates from seawater or groundwater, forms veins in hydrothermal environments, and makes up limestone; recrystallized limestone forms marble. These materials range from ancient to modern geological ages.

Uses & applications

Used in cement, lime, aggregate, glass manufacture, soil treatment, and as a collectible mineral; clear crystals may be ornamental. The pictured small fragment has negligible commercial value.

Geological facts

Calcite effervesces vigorously with dilute hydrochloric acid or household vinegar, especially when powdered. It shows strong double refraction in transparent crystals and commonly breaks along rhombohedral cleavage planes.

Field identification & locations

Likely calcite based on its white color and blocky cleavage, but a field identification requires an acid test and hardness test; gypsum or quartz are alternatives. Common worldwide, especially in limestone regions and hydrothermal veins.