mineral

Orange calcite

Calcite (CaCO₃), likely translucent orange calcite

AI-generated identification · may be incorrect

Usually Mohs hardness 3, vitreous to pearly luster, transparent to translucent, commonly orange from iron or other impurities. Trigonal crystal structure with perfect rhombohedral cleavage; relatively low specific gravity (~2.71).

Identified September 21, 2026More mineral →

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Physical properties

Formation & geological history

Forms in sedimentary limestone, hydrothermal veins, and cave deposits. The specimen appears human-broken or cleaved rather than naturally crystal-faced; age cannot be determined from the photograph.

Uses & applications

Used for cement, lime, aggregate, and industrial calcium carbonate; attractive orange varieties are sold as inexpensive lapidary and decorative specimens.

Geological facts

Calcite effervesces strongly in cold dilute hydrochloric acid. It shows strong birefringence: printed text viewed through a clear fragment may appear doubled.

Field identification & locations

The orange translucent color and prominent cleavage fit calcite, common in the Niagara Escarpment and carbonate rocks around southern Ontario. Confirm with a hardness test against a copper coin or steel knife and dilute acid; fluorite or orange aragonite are less likely alternatives.