mineral

Tumbled orange calcite

Calcite, calcium carbonate (CaCO₃)

AI-generated identification · may be incorrect

Typically honey-yellow to orange, translucent, with a vitreous to pearly luster and white internal cleavage planes. Mohs hardness 3; rhombohedral crystal structure and perfect rhombohedral cleavage; specific gravity about 2.71.

Identified September 17, 2026More mineral →

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Physical properties

Formation & geological history

Forms in sedimentary limestones, hydrothermal veins, caves, and carbonatite deposits, commonly through precipitation from carbonate-rich fluids. Calcite occurs from Precambrian to modern settings; this specimen has been polished into a rounded cabochon-like pebble.

Uses & applications

Used in cement, lime, aggregate, agriculture, and chemical manufacturing; attractive orange material is sold for décor, metaphysical collecting, and inexpensive cabochons. It is generally too soft for durable everyday jewelry.

Geological facts

Orange color commonly results from iron or other trace impurities, while cloudy zones reflect inclusions or fractures. Calcite effervesces visibly in dilute hydrochloric acid, unlike quartz.

Field identification & locations

Identify it by its low hardness, rhombohedral cleavage, and acid reaction; it can be scratched by a steel knife and should not be cleaned with acids. Common sources include Mexico, Brazil, the United States, and China.