gemstone

Tumbled carnelian (likely)

Chalcedony, microcrystalline quartz (SiO₂), iron-oxide colored

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; orange-red to brown-red, translucent at thin edges, with a waxy to glassy luster and no visible cleavage. The rounded shape and polish indicate a tumbled specimen; exact identification is uncertain from the image alone.

Identified September 22, 2026More gemstone →

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Physical properties

Formation & geological history

Carnelian forms when iron-bearing silica-rich fluids fill cavities and fractures, later becoming chalcedony; it occurs in volcanic rocks, commonly from Miocene–recent volcanic terrains. Major sources include India, Brazil, Uruguay, Madagascar, and Botswana.

Uses & applications

Used for beads, cabochons, carvings, ornaments, and inexpensive jewelry; historically valued as a seal-stone and decorative gemstone.

Geological facts

Its red-orange color comes chiefly from dispersed iron oxides or hydroxides. Carnelian grades into orange, brown, and reddish sard, and can resemble heat-treated or dyed agate.

Field identification & locations

Look for a uniformly fine-grained, waxy appearance, translucency, and lack of cleavage; glass may show bubbles, while jasper is usually opaque. Commonly sold as polished tumbles, so testing hardness or viewing under magnification is useful.