mineral

Orange calcite crystal

Calcite (calcium carbonate, CaCO₃)

AI-generated identification · may be incorrect

Typically orange to honey-colored, translucent, with vitreous to pearly luster and prominent rhombohedral cleavage; Mohs hardness 3, trigonal crystal structure, and specific gravity about 2.71. The elongated specimen appears naturally crystalline, possibly with minor quartz or iron-oxide staining.

Identified August 30, 2026More mineral →

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Physical properties

Formation & geological history

Forms in hydrothermal veins, cavities, and sedimentary carbonate environments, commonly colored orange by iron or other trace impurities. Calcite deposits range from ancient Precambrian formations to modern vein systems.

Uses & applications

Used for cement, lime, agricultural soil treatment, and optical/calcareous materials; attractive crystals are sold to mineral collectors and occasionally used decoratively, but it is too soft for most jewelry.

Geological facts

Calcite effervesces strongly with dilute hydrochloric acid and shows birefringence, producing doubled images through clear pieces. Its cleavage and softness distinguish it from harder orange quartz varieties.

Field identification & locations

Common localities include Mexico, the United States, Peru, China, and Morocco. Confirm with acid fizz, hardness testing, and cleavage; avoid scratching the specimen because calcite is soft.