mineral

Blue Calcite

Calcium Carbonate (CaCO3)

Hardness: 3 on Mohs scale; Color: Light blue to pale blue-grey; Luster: Vitreous to waxy; Crystal structure: Trigonal/Rhombohedral; Cleavage: Perfect rhombohedral; Specific gravity: 2.71

Hardness: 3 on Mohs scale
Color: Light blue to pale blue-grey
Luster: Vitreous to waxy

Identified June 4, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 3 on Mohs scale; Color: Light blue to pale blue-grey; Luster: Vitreous to waxy; Crystal structure: Trigonal/Rhombohedral; Cleavage: Perfect rhombohedral; Specific gravity: 2.71

Formation & geological history

Formed through sedimentary processes or as a secondary mineral in igneous and metamorphic rocks. Often precipitating from calcium-rich hydrothermal fluids in limestone caves or hydrothermal veins.

Uses & applications

Used as an ornamental stone, in metaphysical practices (healing crystals), as a source of lime, and for chemical applications in agriculture and industry.

Geological facts

Calcite is famous for its double refraction property. Blue calcite specifically is often acid-washed to give it a characteristic smooth, waxy feel that differs from the rougher texture of other calcite colors.

Field identification & locations

Identify in the field by its 3-way rhombohedral cleavage and its rapid effervescence (bubbling) when exposed to cold dilute hydrochloric acid. It is much softer than quartz or fluorite.