mineral

Blue calcite

Calcite (calcium carbonate, CaCO₃)

AI-generated identification · may be incorrect

Pale blue, translucent-to-opaque, with a vitreous to pearly luster and prominent rhombohedral cleavage; Mohs hardness 3, specific gravity about 2.71. The specimen appears as a rough, crystalline aggregate, though color may be enhanced by lighting or treatment.

Identified August 11, 2026More mineral →

Explore Blue calcite in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Forms when calcium-rich groundwater or hydrothermal fluids precipitate carbonate, commonly in limestone cavities, veins, and sedimentary environments. Most specimens are geologically young relative to their host rocks, ranging from recent deposits to Paleozoic and older formations.

Uses & applications

Primarily collected as a decorative and metaphysical mineral; attractive pieces may be polished or used in carvings. It is not generally suitable for jewelry because of its softness and cleavage, while calcite broadly is important in cement, lime, and agricultural applications.

Geological facts

Calcite effervesces strongly with dilute hydrochloric acid or vinegar, especially when powdered or scratched. Its double refraction is a classic diagnostic property in clear varieties.

Field identification & locations

Commonly found in Mexico, Madagascar, Brazil, the United States, and parts of Europe. Identify it by its blue color, rhombohedral cleavage, softness, and acid reaction; avoid prolonged water or acid exposure.