mineral

Calcite on Host Rock

Calcium Carbonate (CaCO3)

Hardness: 3 (Mohs scale), Color: White to yellowish-white, Luster: Vitreous to pearly, Crystal structure: Trigonal/Rhombohedral, Cleavage: Perfect rhombohedral

Identified June 21, 2026More mineral →

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Physical properties

Hardness: 3 (Mohs scale), Color: White to yellowish-white, Luster: Vitreous to pearly, Crystal structure: Trigonal/Rhombohedral, Cleavage: Perfect rhombohedral

Formation & geological history

Formed via chemical precipitation in hydrothermal veins or sedimentary environments where calcium-rich fluids interact with CO2. Often found in limestone or marble host rocks.

Uses & applications

Used in the manufacture of cement, as an agricultural soil treatment, in the chemical industry, and as decorative mineral specimens.

Geological facts

Calcite is one of the most common minerals on Earth. It is famous for its double refraction and its high reactivity to weak acids like vinegar.

Field identification & locations

Identify in the field by its softness (can be scratched by a copper coin) and its effervescence (bubbles) when a drop of cold dilute hydrochloric acid or vinegar is applied. Found globally in sedimentary basins.