mineral

Blue Calcite

Calcium Carbonate (CaCO3)

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

Identified July 3, 2026More mineral →

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Physical properties

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

Formation & geological history

Forms in sedimentary environments through chemical precipitation or in metamorphic environments as marble. Blue coloration is often caused by the inclusion of various metal ions or radiation-induced color centers within the crystal lattice.

Uses & applications

Primarily used as a decorative stone, lapidary material for carvings and spheres, and as a popular specimen for mineral collectors and metaphysical practitioners.

Geological facts

Calcite is one of the most common minerals on Earth, but the soft sky-blue variety is quite distinct. It is highly reactive to weak acids like vinegar, which will cause it to effervesce (bubble).

Field identification & locations

Identified by its pale blue color, rhombohedral cleavage planes, and low hardness (it can be scratched by a copper penny). Large deposits are notably found in Madagascar, Mexico, and Brazil.