mineral

Blue Calcite

Calcite (Calcium Carbonate, CaCO3)

Hardness: 3 on Mohs scale; Color: Sky blue to deep sea blue with white streaks; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: Perfect rhombohedral

Hardness: 3 on Mohs scale
Color: Sky blue to deep sea blue with white streaks
Luster: Vitreous to waxy

Identified July 1, 2026More mineral →

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Physical properties

Hardness: 3 on Mohs scale; Color: Sky blue to deep sea blue with white streaks; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: Perfect rhombohedral

Formation & geological history

Formed through sedimentary processes or as a secondary mineral in igneous and metamorphic rocks. It often precipitates from calcium-rich hydrothermal fluids or seawater.

Uses & applications

Used primarily in jewelry as cabochons, for decorative carvings, as a spiritual aid in crystal healing, and as a source of calcium in various industrial processes.

Geological facts

Blue calcite is one of the softest minerals used in jewelry, meaning it is easily scratched. It is often found in massive form rather than distinct crystals. It is highly reactive to dilute acids.

Field identification & locations

Identify in the field by its distinct waxy luster, sky-blue color, and its softness (can be scratched by a copper penny or steel knife). It will effervesce when in contact with hydrochloric acid. Found commonly in Mexico and Madagascar.