Orange Calcite

Physical Properties

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

Formation & Geological History

Formed through sedimentary processes, primarily from the chemical precipitation of calcium carbonate in marine environments or hydrothermal veins. It can be found in cave formations or as a major constituent of limestone and marble.

Uses & Applications

Broadly used in the production of cement and lime for construction. As a mineral specimen, it is popular for metaphysical uses, decorative carvings, and as educational samples for collectors.

Geological Facts

Orange calcite gets its distinct hue from inclusions of hematite or other iron oxides. It is famous for its 'double refraction' property, where a ray of light passing through it is split into two, though this is harder to see in opaque orange varieties.

Field Identification & Locations

Identify in the field by its rhombohedral cleavage (it breaks into tilted cubes/parallelograms) and its reaction to dilute hydrochloric acid (it will fizz). It is commonly found globally, with high-quality orange specimens coming from Mexico and Brazil.

Identified on: 4/27/2026

Mode: Standard