mineral

Polished carnelian

Carnelian, a reddish-orange cryptocrystalline chalcedony (SiO₂), colored mainly by iron oxides.

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; translucent orange, red-brown, or honey coloration with vitreous to waxy luster. It has a trigonal microcrystalline quartz structure, no cleavage, conchoidal fracture, and specific gravity around 2.60.

Identified September 15, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures, later acquiring red coloration through iron oxidation; deposits range from Precambrian to Cenozoic. This example is tumbled and polished.

Uses & applications

Used for cabochons, beads, carvings, seals, and ornamental objects; attractive quality is common but valued in jewelry.

Geological facts

Carnelian is a variety of chalcedony, closely related to sard; its color may deepen with gentle heating or prolonged sunlight exposure.

Field identification & locations

Identify by its warm red-orange translucency, smooth waxy appearance, hardness, and lack of visible large crystals; common sources include India, Brazil, Uruguay, Madagascar, and Botswana.