gemstone

Polished carnelian/chalcedony pebble

Microcrystalline quartz (SiO₂), likely iron-stained chalcedony

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent cream to honey-orange with reddish-brown dendritic or fracture staining; waxy to glassy luster and no visible cleavage. Quartz has a trigonal crystal structure, though chalcedony is cryptocrystalline; specific gravity is about 2.6.

Identified August 10, 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 orange-brown coloration. The pictured piece is tumbled or cabochon-polished; its exact geological age and host rock cannot be determined visually.

Uses & applications

Used for beads, cabochons, carvings, and decorative objects; durable enough for jewelry. Common specimens generally have modest commercial value.

Geological facts

Carnelian is the orange-red variety of chalcedony; paler honey material may be called sard or simply orange chalcedony. Color can deepen after heating or prolonged exposure to iron-rich solutions.

Field identification & locations

Look for strong translucency, smooth waxy polish, quartz-like hardness, and absence of cleavage; it should scratch ordinary glass but not be scratched by a steel blade. Common sources include India, Brazil, Uruguay, Madagascar, and Namibia.