mineral

Blue calcite (likely)

Calcite, calcium carbonate (CaCO₃)

AI-generated identification · may be incorrect

Pale blue, translucent, glassy to pearly luster with prominent rhombohedral cleavage; Mohs hardness 3, typically white streak, and relatively low density (specific gravity about 2.7). The rounded edges suggest a polished or naturally worn fragment.

Identified September 13, 2026More mineral →

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Physical properties

Formation & geological history

Forms in sedimentary carbonate rocks, hydrothermal veins, and caves when calcium-rich fluids precipitate calcite. Blue coloration commonly results from trace impurities or inclusions; the specimen’s exact geological age cannot be determined from the image.

Uses & applications

Used as an ornamental and lapidary material, though blue calcite is too soft for most durable jewelry. Calcite is also important industrially in cement, lime, aggregate, glass, and soil treatment.

Geological facts

Calcite effervesces strongly with dilute hydrochloric acid and shows birefringence under transparent edges. Blue calcite is often confused with blue aragonite, celestite, fluorite, or dyed material.

Field identification & locations

Common localities include Mexico, Argentina, Brazil, Madagascar, and the United States. Confirm with a hardness test, rhombohedral cleavage, and acid reaction; avoid scratching the visible surface.