Rock Identifier
Polished carnelian (Carnelian, a chalcedony variety of microcrystalline quartz (SiO₂), colored mainly by iron oxides) — gemstone
gemstone

Polished carnelian

Carnelian, a chalcedony variety of microcrystalline quartz (SiO₂), colored mainly by iron oxides

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent orange-red to reddish brown, vitreous to waxy luster, cryptocrystalline structure, and no visible cleavage. The rounded, polished form is likely a cabochon or tumbled stone.

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Physical properties

Hardness 6.5–7 Mohs; translucent orange-red to reddish brown, vitreous to waxy luster, cryptocrystalline structure, and no visible cleavage. The rounded, polished form is likely a cabochon or tumbled stone.

Formation & geological history

Forms when iron-bearing silica-rich groundwater fills cavities and fractures, with oxidation producing the red-orange color; commonly associated with volcanic rocks and ancient sedimentary gravels. Deposits occur from Precambrian to recent ages.

Uses & applications

Used for beads, cabochons, carvings, seals, and ornamental objects; durable enough for everyday jewelry. Common commercial material is relatively affordable.

Geological facts

Carnelian is a traditional variety of agate/chalcedony, and its color may be enhanced by heating. Natural stones often show subtle bands, cloudy zones, or uneven color.

Field identification & locations

Identify it by its warm translucent orange-red color, glassy/waxy polish, quartz hardness, and lack of cleavage; it should resist scratching by a steel knife. Common sources include India, Brazil, Uruguay, Madagascar, and Germany.