mineral

Orange Calcite

Calcium Carbonate (CaCO3)

Hardness: 3 on Mohs scale; Color: Pale orange to deep amber; Luster: Vitreous to waxy/greasy; Crystal Structure: Trigonal/Rhombohedral; Cleavage: Perfect rhombohedral in three directions; Specific Gravity: 2.71

Hardness: 3 on Mohs scale
Color: Pale orange to deep amber
Luster: Vitreous to waxy/greasy

Identified March 22, 2026More mineral →

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Physical properties

Formation & geological history

Formed through sedimentary processes, often as a precipitate in marine environments or through hydrothermal activity. It is a common constituent of sedimentary rocks like limestone. Geological age varies greatly from Precambrian to Cenozoic.

Uses & applications

Used primarily as decorative stones, in lapidary work (cabochons, carvings), and as metaphysical healing crystals. Industrial uses for calcite include acid neutralization, chemical industry feedstock, and as a soil conditioner.

Geological facts

Orange calcite is often 'acid-washed' by dealers to give it a smooth, waxy finish that prevents the mineral from feeling chalky. It is famous for its double refraction (birefringence), where light entering the crystal splits into two rays.

Field identification & locations

Identify in the field by its 3-way rhombohedral cleavage and its rapid effervescence (bubbling) when a drop of cold dilute hydrochloric acid is applied. Commonly found in Mexico, Brazil, and the USA (notably Utah). Collectors should look for 'glassy' transparency.