mineral

Calcite

Calcium Carbonate (CaCO3)

Hardness: 3 on Mohs scale; Color: Colorless, white, or pale hues; Luster: Vitreous to pearly; Crystal Structure: Trigonal/Rhombohedral; Cleavage: Perfect rhombohedral in three directions; Specific Gravity: 2.71

Hardness: 3 on Mohs scale
Color: Colorless, white, or pale hues
Luster: Vitreous to pearly

Identified July 5, 2026More mineral →

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Physical properties

Formation & geological history

Commonly forms as a sedimentary mineral through chemical precipitation in marine environments or as an evaporite. It is the primary component of limestone and marble.

Uses & applications

Used in the manufacture of cement and mortar, as a neutralized in the chemical industry, in agriculture as a soil treatment, and occasionally as a display specimen for collectors.

Geological facts

Calcite exhibits strong double refraction; if you place a clear crystal over a line, the line will appear double. It is also the primary mineral found in stalactites and stalagmites in caves.

Field identification & locations

Can be identified in the field by its softness (can be scratched by a copper coin) and its rapid effervescence (bubbling) when exposed to cold dilute hydrochloric acid or vinegar.