mineral

Likely calcite fragment

Calcite (calcium carbonate, CaCO₃)

AI-generated identification · may be incorrect

Cream to pale yellow, translucent to opaque, with a dull-to-glassy luster and likely rhombohedral cleavage; Mohs hardness 3, specific gravity about 2.71. The blurry image limits confirmation; it may also be a pale limestone or aragonite fragment.

Identified September 20, 2026More mineral →

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Physical properties

Formation & geological history

Calcite commonly precipitates from groundwater or seawater, forms in sedimentary limestone and marble, and occurs in hydrothermal veins. Its age could range from modern deposits to ancient Paleozoic or older rocks.

Uses & applications

Used in cement, lime, aggregate, soil treatment, and chemical manufacturing; transparent crystals are collectible, though this fragment appears low-grade.

Geological facts

Calcite effervesces vigorously with dilute hydrochloric acid or household vinegar, especially when powdered or freshly scratched. It commonly shows rhombohedral cleavage and may display double refraction.

Field identification & locations

Common worldwide, especially in limestone regions, caves, hydrothermal veins, and marble. Test with a steel nail (usually scratches it) and dilute acid; avoid acid on valuable specimens.