mineral

Tumbled carnelian/chalcedony

Microcrystalline quartz (SiO₂), likely iron-stained chalcedony

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent honey-brown to orange with cloudy gray areas, waxy-to-glassy luster, and no visible cleavage. Its rounded shape and glossy surface indicate water-worn or mechanically tumbled chalcedony.

Identified August 30, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures, with iron oxides producing the orange-brown color; commonly associated with volcanic rocks, generally formed from Paleozoic to Cenozoic deposits. Exact age cannot be determined from the photograph.

Uses & applications

Used for beads, cabochons, carvings, and inexpensive jewelry; attractive polished pieces are popular as pocket stones and lapidary material.

Geological facts

Carnelian is the orange-red variety of chalcedony, while brown or paler material is often marketed as sard or iron-stained chalcedony. Heating can intensify its red-orange color.

Field identification & locations

Identify it by its waxy translucence, smooth conchoidal fracture, lack of cleavage, and ability to scratch ordinary glass; it should not show crystal faces. Common sources include India, Brazil, Uruguay, Madagascar, and the western United States.