Rock Identifier
Carnelian (Orange chalcedony, microcrystalline quartz (SiO₂)) — mineral
mineral

Carnelian

Orange chalcedony, microcrystalline quartz (SiO₂)

AI-generated identification · may be incorrect

Typically Mohs hardness 6.5–7, translucent orange to reddish-orange, with waxy-to-glassy luster and no visible cleavage. Its color comes mainly from iron oxide inclusions; the specimen appears tumbled or naturally rounded.

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Physical properties

Typically Mohs hardness 6.5–7, translucent orange to reddish-orange, with waxy-to-glassy luster and no visible cleavage. Its color comes mainly from iron oxide inclusions; the specimen appears tumbled or naturally rounded.

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures in volcanic rocks, later becoming chalcedony; iron produces the orange coloration. Deposits range from Paleozoic to recent geological ages.

Uses & applications

Used for beads, cabochons, carvings, seals, and inexpensive jewelry; historically valued as an ornamental stone.

Geological facts

Carnelian is a cryptocrystalline variety of quartz and grades into sard when darker red-brown. Heating can intensify or imitate its color.

Field identification & locations

Identify by its even orange color, translucency, waxy surface, and quartz-like hardness; it should resist scratching by a steel blade. Common sources include India, Brazil, Uruguay, Madagascar, and Germany.