gemstone

Orange chalcedony (carnelian)

Microcrystalline quartz, SiO₂; orange variety of chalcedony

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; translucent orange to reddish-orange, vitreous to waxy luster, cryptocrystalline quartz with no visible cleavage and conchoidal fracture. The rounded, glossy appearance suggests a polished or tumbled piece, possibly lightly heat-treated or coated.

Identified August 23, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures in volcanic rocks, precipitating microscopic quartz fibers over time. Deposits range from Precambrian to Cenozoic and commonly occur in basaltic terrains and weathered volcanic sediments.

Uses & applications

Used for cabochons, beads, carvings, seals, and ornamental objects; durable enough for jewelry and decorative stonework. Common specimens typically have modest collector value.

Geological facts

Carnelian’s color comes mainly from iron oxides and hydroxides; heating can intensify the orange-red color. It is a variety of chalcedony rather than a separate mineral species.

Field identification & locations

Identify it by its uniform orange translucency, waxy/vitreous luster, conchoidal fracture, and hardness that resists scratching by steel. Common sources include India, Brazil, Uruguay, Madagascar, and Germany.