gemstone

Carnelian (red-orange chalcedony)

Chalcedony, cryptocrystalline SiO₂; quartz-group mineral

AI-generated identification · may be incorrect

Typically translucent orange-red with a waxy to vitreous luster and no visible crystals; Mohs hardness 6.5–7, conchoidal fracture, and specific gravity about 2.60. The pictured piece appears polished or naturally fractured, though its small size and lighting limit certainty.

Identified September 3, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures in volcanic rocks, with iron oxides producing the orange-red color. Deposits commonly formed during Cenozoic and older volcanic episodes.

Uses & applications

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

Geological facts

Carnelian is a colored variety of chalcedony, often graded by saturation and translucency. Heating or dyeing can enhance its color.

Field identification & locations

Identify by its orange-red color, waxy appearance, hardness, and lack of cleavage; it should scratch glass but not be scratched by a steel knife easily. Common sources include India, Brazil, Uruguay, Madagascar, and Germany.