mineral

Blue Calcite

Calcium Carbonate (CaCO3)

Hardness: 3.0 (Mohs scale), Color: Sky blue to pale lavender, Luster: Vitreous to waxy/pearly, Crystal Structure: Trigonal/Hexagonal, Cleavage: Perfect rhombohedral in three directions, Specific Gravity: 2.71

Hardness: 3

Identified July 18, 2026More mineral →

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Physical properties

Formation & geological history

Formed through sedimentary processes or hydrothermal precipitation in marine environments and limestone caves. Large deposits often involve metamorphic transformation of limestone into marble.

Uses & applications

Primarily used as a decorative stone, in lapidary work, as a collector's mineral, and in metaphysical practices. Industrial calcite is used in cement, antacids, and as a soil conditioner.

Geological facts

Calcite is one of the most common minerals on Earth, but the blue variety is specifically colored by fine inclusions of other minerals or light scattering. It is very soft and will effervesce (fizz) if a drop of dilute acid is applied to it.

Field identification & locations

Identify in the field by its distinct rhombohedral cleavage, softness (can be scratched by a copper penny), and reaction to acid. It is commonly found in Mexico, Brazil, and South Africa.