mineral

Tumbled pale green mineral specimen, likely calcite

Calcite (CaCO₃), tentative identification

AI-generated identification · may be incorrect

Whitish to pale green, cloudy/translucent, with a dull to vitreous luster and likely rhombohedral cleavage; Mohs hardness 3 and specific gravity about 2.71. The blocky shape and apparent cleavage are consistent with calcite, though the image is insufficient for certainty.

Identified August 9, 2026More mineral →

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Physical properties

Formation & geological history

Calcite commonly forms in limestone, marble, hydrothermal veins, and cavities; individual specimens may range from ancient sedimentary deposits to modern vein growth. Color can result from impurities such as chlorite or other minerals.

Uses & applications

Used in cement, lime, construction aggregate, soil treatment, and optical/calcareous decorative specimens; attractive crystals are collected but this piece appears low-grade.

Geological facts

Calcite effervesces readily with dilute hydrochloric acid or strong vinegar, unlike most quartz. It is birefringent and commonly shows rhombohedral cleavage rather than cubic cleavage.

Field identification & locations

Test cautiously: it should scratch with a steel knife, fail to scratch glass, and fizz with acid on a fresh surface; do not acid-test valuable specimens. Common worldwide, especially in limestone regions, Mexico, Iceland, and the United States.