mineral

Calcite

Calcium Carbonate (CaCO3)

Hardness: 3 on Mohs scale, Color: Yellow, white, or colorless, Luster: Vitreous to pearly, Crystal structure: Trigonal, Cleavage: Perfect rhombohedral in three directions, Specific gravity: 2.71

Identified August 5, 2026More mineral →

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Physical properties

Hardness: 3 on Mohs scale, Color: Yellow, white, or colorless, Luster: Vitreous to pearly, Crystal structure: Trigonal, Cleavage: Perfect rhombohedral in three directions, Specific gravity: 2.71

Formation & geological history

Formed in sedimentary environments through the precipitation of calcium carbonate from water, as well as in hydrothermal veins and metamorphic marbles.

Uses & applications

Used in construction (as limestone and marble), manufacturing of cement, agriculture to neutralize acidic soils, and in optical devices.

Geological facts

Calcite exhibits strong double refraction (birefringence), meaning light passing through it is split into two rays, creating a double image.

Field identification & locations

Easily identified by its characteristic rhombohedral cleavage and effervescence (bubbling) when tested with dilute hydrochloric acid. Found worldwide.