mineral
Orange calcite
Calcite (calcium carbonate, CaCO₃)
AI-generated identification · may be incorrectTypically honey-orange to yellow, translucent to opaque, with a glassy-to-waxy luster and commonly massive or granular texture. Mohs hardness 3, perfect rhombohedral cleavage, white streak, and specific gravity about 2.71; the rounded edges indicate tumbling or natural abrasion.
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Physical properties
Typically honey-orange to yellow, translucent to opaque, with a glassy-to-waxy luster and commonly massive or granular texture. Mohs hardness 3, perfect rhombohedral cleavage, white streak, and specific gravity about 2.71; the rounded edges indicate tumbling or natural abrasion.
Formation & geological history
Forms when calcium-rich groundwater precipitates carbonate in cavities, veins, caves, and sedimentary environments; orange color commonly reflects iron or other trace impurities. Calcite deposits range from recent to hundreds of millions of years old.
Uses & applications
Used for cement, lime, aggregate, soil treatment, and chemical manufacture; attractive orange specimens are sold to mineral collectors and occasionally used as decorative stone.
Geological facts
Calcite effervesces vigorously with dilute hydrochloric acid or strong vinegar, unlike most orange quartz varieties. It is much softer than quartz and can be scratched by a steel knife.
Field identification & locations
Common in Mexico, the United States, Brazil, Peru, and China. Confirm with hardness, rhombohedral cleavage, and acid reaction; avoid confusing it with orange aragonite or carnelian.
