mineral

Orange Calcite

Calcium Carbonate (CaCO3)

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

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

Identified February 10, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed through sedimentary processes, often precipitated from marine environments or in hydro-thermal veins and caves. It can be found in a wide range of geological ages from Precambrian to recent deposits.

Uses & applications

Used primarily for decorative lapidary work, carvings, and as a collector's mineral. In industry, calcite is used as a flux in glass-making and for neutralizing acids.

Geological facts

Orange calcite is often called the 'stone of the mind,' believed by some to improve memory. It exhibits double refraction (birefringence), where light passing through it splits into two rays.

Field identification & locations

Identify in the field by its rhombohedral cleavage and its effervescence (bubbling) when in contact with dilute hydrochloric acid. It is commonly found in Mexico, Brazil, and the USA (as in the Tri-State district).