mineral

Blue Calcite

Calcium Carbonate (CaCO3)

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

Hardness: 3 on Mohs scale
Color: Pale baby blue to deep sky blue
Luster: Vitreous to waxy

Identified February 14, 2026More mineral →

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Physical properties

Formation & geological history

Formed through sedimentary processes, typically in marine environments or through hydrothermal precipitation. It often occurs in massive form in limestone deposits that have under gone mild metamorphism. Found in geological formations ranging from the Paleozoic to the Cenozoic eras.

Uses & applications

Predominantly used as a decorative stone, lapidary material for carvings and cabochons, and in metaphysical practices. Industrially, calcite is used in cement, fertilizers, and as an acid neutralizer.

Geological facts

Blue calcite is known for its 'soapy' or waxy feel when polished. It is extremely soft, meaning it can be scratched by a copper penny. Unlike blue quartz or lace agate, it will effervesce (fizz) if a drop of weak hydrochloric acid is applied to it.

Field identification & locations

Identify in the field by its pale blue color, rhombohedral cleavage planes, and low hardness. Commonly found in large deposits in Mexico, Madagascar, and Brazil. Collectors should look for specimens with a deep color and minimal white 'shock' fractures.