Rock Identifier
Orange calcite (Calcite (CaCO₃)) — mineral
mineral

Orange calcite

Calcite (CaCO₃)

AI-generated identification · may be incorrect

Typically honey-orange to pale orange, with a vitreous to pearly luster and translucent appearance; Mohs hardness 3, rhombohedral cleavage, trigonal crystal system, and specific gravity about 2.71. The specimen appears tumbled or naturally rounded, so crystal faces are indistinct.

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Physical properties

Typically honey-orange to pale orange, with a vitreous to pearly luster and translucent appearance; Mohs hardness 3, rhombohedral cleavage, trigonal crystal system, and specific gravity about 2.71. The specimen appears tumbled or naturally rounded, so crystal faces are indistinct.

Formation & geological history

Forms in sedimentary limestone, hydrothermal veins, and caves through precipitation of calcium carbonate; orange color commonly comes from iron or other trace impurities. Calcite deposits range from Precambrian to recent in age.

Uses & applications

Used in cement, lime, glass, soil treatment, and chemical industries; attractive orange specimens are sold as inexpensive display minerals and occasionally carved ornaments.

Geological facts

Calcite effervesces strongly in dilute hydrochloric acid and can scratch with a steel knife but not glass. Its strong birefringence can produce doubled images through clear fragments.

Field identification & locations

Common worldwide, including Mexico, the United States, Brazil, Iceland, and China. Identify it by rhombohedral cleavage, low hardness, acid reaction, and orange coloration; confirm against similarly colored aragonite by cleavage and crystal form.