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; Specific Gravity: 2.71

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

Identified July 11, 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; Specific Gravity: 2.71

Formation & geological history

Formed through sedimentary processes or in hydrothermal veins, often found in large massive forms rather than distinct crystals. It is frequently associated with limestone and marble formations.

Uses & applications

Primarily used for ornamental purposes, lapidary work (cabochons, carvings, palm stones), and by collectors for its calming aesthetic. It is also used in the manufacturing of cement and lime in its more common forms.

Geological facts

Blue calcite is often 'acid-washed' by dealers to give it a smooth, waxy feel and to enhance its color. It is a very soft mineral, making it unsuitable for rings but excellent for decorative carvings.

Field identification & locations

Identified in the field by its pale blue color, rhombohedral cleavage, and the fact that it will effervesce (fizz) when in contact with dilute hydrochloric acid. It is commonly found in large deposits in Mexico and Madagascar.