mineral

Blue Calcite

Calcite (CaCO3)

Hardness: 3 on Mohs scale; Color: Sky blue to pale blue with white banding; Luster: Vitreous to waxy; Crystal structure: Trigonal/Rhombohedral; Cleavage: Perfect rhombohedral in three directions; Specific gravity: 2.71

Hardness: 3 on Mohs scale
Color: Sky blue to pale blue with white banding
Luster: Vitreous to waxy

Identified May 9, 2026More mineral →

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Physical properties

Formation & geological history

Formed through sedimentary processes, primarily the chemical precipitation of calcium carbonate or from the remains of marine organisms. It can also occur in metamorphic environments as marble or in igneous hydrothermal veins.

Uses & applications

Used in the manufacture of cement and lime, as a flux in glassmaking, in the ornamental stone industry, and widely collected as a metaphysical or decorative mineral specimen. Occasionally used for cabochons in jewelry.

Geological facts

Calcite is one of the most common minerals on Earth. The blue variety is specifically known for its calming appearance and is a popular 'worry stone' in the gem trade. High-quality blue calcite often comes from large deposits in Madagascar and Mexico.

Field identification & locations

Identify in the field by its 3-way rhombohedral cleavage and its reaction (effervescence) when touched with dilute hydrochloric acid. It is much softer than quartz or fluorite, easily scratched by a copper coin.