mineral

Blue Calcite

Calcium Carbonate (CaCO3)

Hardness: 3 on Mohs scale; Color: Sky blue to deep blue; Luster: Vitreous to waxy/greasy; Crystal Structure: Trigonal/Rhombohedral; Cleavage: Perfect rhombohedral in three directions; Specific Gravity: 2.71

Hardness: 3 on Mohs scale
Color: Sky blue to deep blue
Luster: Vitreous to waxy/greasy

Identified July 10, 2026More mineral →

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Physical properties

Formation & geological history

Forms in sedimentary environments through chemical precipitation or in metamorphic environments as marble. This blue variety often forms in hydrothermal environments or via recrystallization of limestone.

Uses & applications

Primarily used as a decorative stone, in lapidary work for cabochons and carvings, and as a popular specimen for mineral collectors and metaphysical practitioners.

Geological facts

Blue Calcite is a very soft stone, making it easy to carve but fragile for jewelry use. The blue color is often attributed to tiny inclusions or structural defects within the crystal lattice.

Field identification & locations

Identifiable by its rhombohedral cleavage, softness (can be scratched by a copper penny), and effervescence when exposed to weak acid (HCl). Commonly found in Mexico, Africa, and Brazil.