mineral

Blue Calcite

Calcium Carbonate (CaCO3)

Hardness: 3 on Mohs scale; Color: Pale blue to sky blue; Luster: Vitreous to waxy; Crystal structure: Trigonal/Rhombohedral; Cleavage: Perfect rhombohedral in three directions; Specific gravity: 2.71

Hardness: 3 on Mohs scale
Color: Pale blue to sky blue
Luster: Vitreous to waxy

Identified July 10, 2026More mineral →

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Physical properties

Hardness: 3 on Mohs scale; Color: Pale blue to sky blue; Luster: Vitreous to waxy; Crystal structure: Trigonal/Rhombohedral; Cleavage: Perfect rhombohedral in three directions; Specific gravity: 2.71

Formation & geological history

Formed through sedimentary processes or as a secondary mineral in igneous rocks via hydrothermal activity. It is often found in large massive forms rather than distinct crystals within metamorphic and sedimentary environments.

Uses & applications

Used primarily as a decorative stone, in lapidary work for cabochons and carvings, and as a popular metaphysical or collector mineral. Industrially, calcite is used in cement and lime.

Geological facts

Blue calcite is known for its 'soapy' or waxy feel due to its low hardness. It is sensitive to acids and will effervesce (fizz) if a drop of weak acid is applied, which is a key diagnostic test for carbonates.

Field identification & locations

Identify in the field by its distinct blue color, rhombohedral cleavage planes, and softness (can be scratched by a copper penny). It is commonly sourced from Mexico and Madagascar.