mineral

Calcite

Calcite (Calcium Carbonate, CaCO3)

Hardness: 3 on Mohs scale; Color: white to off-white/yellowish; Luster: vitreous to pearly; Crystal structure: Trigonal (rhombohedral cleavage); Cleavage: perfect in three directions; Specific gravity: 2.71

Hardness: 3 on Mohs scale
Color: white to off-white/yellowish
Luster: vitreous to pearly

Identified May 24, 2026More mineral →

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Physical properties

Formation & geological history

Formed through chemical precipitation in sedimentary environments, hydrothermal veins, or as a primary mineral in igneous carbonatites.

Uses & applications

Used in the manufacture of cement and mortar, as a soil conditioner in agriculture, in the optical industry (high-quality crystals), and as a collector's specimen.

Geological facts

Calcite exhibits double refraction, where an image viewed through a clear crystal appears doubled. It is the primary component of limestone and marble.

Field identification & locations

Identified by its rhombohedral cleavage and its vigorous effervescence (fizzing) when in contact with dilute hydrochloric acid. Commonly found in limestone quarries and mineral veins.