mineral

Orange calcite fragment

Calcite (calcium carbonate, CaCO₃)

AI-generated identification · may be incorrect

Typically honey-orange to pale yellow, translucent to opaque, with vitreous to pearly luster and prominent rhombohedral cleavage; Mohs hardness 3 and specific gravity about 2.71. The granular, cleavage-rich appearance is consistent with calcite, though the image alone cannot confirm identity.

Identified September 16, 2026More mineral →

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Physical properties

Formation & geological history

Calcite commonly forms in sedimentary limestone and marble, hydrothermal veins, cavities, and caves; its age can range from recent deposits to Precambrian rocks. Orange coloration may result from iron or other trace impurities.

Uses & applications

Used in cement, lime, aggregate, glass, soil treatment, and chemical industries; transparent or strongly colored crystals are collected and occasionally used ornamentally. This small rough piece has modest commercial value.

Geological facts

Calcite effervesces vigorously with dilute hydrochloric acid or vinegar, though vinegar may react slowly. It is famous for strong birefringence: clear pieces can produce doubled images.

Field identification & locations

Look for rhombohedral cleavage, low hardness, and acid fizzing; it should scratch easily with a steel nail or knife. Common sources include Mexico, the United States, Iceland, Brazil, and China.