mineral

Blue Calcite

Calcium Carbonate (CaCO3)

Hardness: 3 on Mohs scale; Color: light sky blue to pale blue; Luster: vitreous to waxy/pearly; Crystal System: Trigonal; Cleavage: Perfect rhombohedral in three directions; Specific Gravity: 2.71

Hardness: 3 on Mohs scale
Color: light sky blue to pale blue
Luster: vitreous to waxy/pearly

Identified July 21, 2026More mineral →

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Physical properties

Hardness: 3 on Mohs scale; Color: light sky blue to pale blue; Luster: vitreous to waxy/pearly; Crystal System: Trigonal; Cleavage: Perfect rhombohedral in three directions; Specific Gravity: 2.71

Formation & geological history

Formed through sedimentary processes, primarily in marine environments where calcium carbonate precipitates out of water or accumulates from shell/coral fragments. It can also form through hydrothermal activity and within metamorphic marble.

Uses & applications

Used in home decor, lapidary carvings, metaphysical practices, and as a source for calcium in chemical industries. High-quality specimens are popular among mineral collectors.

Geological facts

Calcite is the most common carbonate mineral. Blue calcite is particularly associated with serene environments and is often sold as a 'soothing stone.' It reacts strongly (effervesces) with cold dilute hydrochloric acid.

Field identification & locations

Identify in the field by its rhombohedral cleavage, its softness (it can be scratched by a copper penny but not a fingernail), and the 'soapy' or waxy feel common in many specimens. Often found in Mexico and Madagascar.