mineral

Calcite geode or botryoidal calcite

Calcite (calcium carbonate, CaCO₃)

AI-generated identification · may be incorrect

Cream-white, translucent to opaque mineral with pearly-to-vitreous luster and commonly rhombohedral cleavage; Mohs hardness 3, specific gravity about 2.71. The rough, rounded surface and sparkling interior suggest a small calcite geode or botryoidal aggregate.

Identified August 11, 2026More mineral →

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Physical properties

Formation & geological history

Forms when calcium-carbonate-rich groundwater deposits crystals lining a cavity, often in volcanic rocks, limestone, or hydrothermal veins; age depends on its host formation. It may also represent weathered or broken cave/deposit calcite.

Uses & applications

Used for cement, lime, agricultural soil treatment, and chemical production; attractive specimens are collected, though this piece is not typically gem-quality.

Geological facts

Calcite effervesces strongly with dilute hydrochloric acid or vinegar, though vinegar may react slowly. It shows strong birefringence and can be distinguished from quartz by its much lower hardness.

Field identification & locations

Common in limestone regions, caves, hydrothermal veins, and basaltic geodes worldwide; test cautiously with a steel point and dilute acid, and avoid scratching display surfaces.