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 April 1, 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 in sedimentary environments through chemical precipitation or as a primary mineral in igneous and metamorphic rocks. Most blue varieties are found in metamorphic marble or hydrothermal veins.

Uses & applications

Used primarily as decorative carvings, tumbled stones for metaphysical use, and collected as mineral specimens. In industry, calcite is used for lime, cement, and as a filler.

Geological facts

Blue calcite is known for its 'soapy' or waxy feel. When a drop of dilute hydrochloric acid is placed on it, it will effervesce (fizz) due to the release of carbon dioxide.

Field identification & locations

Identify in the field by its softness (can be scratched by a copper coin), rhombohedral cleavage planes, and its reaction to acid. Notable deposits are found in Mexico and Madagascar.