mineral

Calcite in Matrix

Calcium Carbonate (CaCO3) on Sedimentary Host Rock

Hardness: 3 on Mohs scale; Color: Creamy white to pale yellow crystalline center in grey/brown matrix; Luster: Vitreous to pearly; Crystal structure: Trigonal/Rhombohedral; Cleavage: Perfect in three directions.

Hardness: 3 on Mohs scale
Luster: Vitreous to pearly

Identified June 24, 2026More mineral →

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Physical properties

Formation & geological history

Formed primarily through chemical precipitation in sedimentary environments or hydrothermal veins where calcium-rich fluids crystallize. Commonly found in limestone or dolostone cavities.

Uses & applications

Calcite is used in the manufacture of cement and mortar, as a flux in glassmaking, in soil treatment, and as a decorative mineral specimen for collectors.

Geological facts

Calcite crystals will react and effervesce (fizz) when they come into contact with dilute hydrochloric acid or even strong vinegar. It is one of the most common minerals on Earth's crust.

Field identification & locations

Identify in the field by its rhombohedral cleavage and soft surface that can be scratched by a copper penny or steel knife. Frequently found in limestone quarries or mountain outcrops.

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

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Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

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mineral