gemstone

Tumbled carnelian agate

Cryptocrystalline quartz (SiO₂), chalcedony variety with iron-oxide coloration

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; translucent orange-red to brown with cream chalcedony bands, waxy to vitreous luster, and no visible cleavage. Its rounded shape and glossy surface indicate mechanical tumbling and polishing.

Identified August 10, 2026More gemstone →

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Physical properties

Formation & geological history

Silica-rich groundwater filled cavities in volcanic rock, forming chalcedony; iron oxides produced the red-orange color. Agates commonly formed in Paleozoic–Cenozoic volcanic environments, though the specimen’s exact age cannot be determined visually.

Uses & applications

Used for cabochons, beads, carvings, ornaments, and inexpensive jewelry; polished pieces are popular collectors’ specimens.

Geological facts

Carnelian is the orange-red variety of chalcedony; paler material may be heat-treated to intensify its color. The cream-red pattern suggests agate or jasper-like chalcedony rather than pure carnelian.

Field identification & locations

Identify by its waxy luster, hardness, translucency, conchoidal fracture, and lack of cleavage; common sources include Brazil, Uruguay, India, Madagascar, and Botswana. A steel blade should not easily scratch it, while quartz can scratch glass.