gemstone

Tumbled carnelian (likely)

Cryptocrystalline quartz, SiO₂; reddish chalcedony colored mainly by iron oxides

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; orange-red to brown, vitreous to waxy luster, translucent edges, no visible cleavage, and conchoidal fracture. The smooth rounded form indicates mechanical tumbling and polishing.

Identified September 4, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures, with iron impurities producing the red-orange color; deposits range from Paleozoic to Cenozoic in age. Common sources include India, Brazil, Uruguay, Madagascar, and the United States.

Uses & applications

Used for beads, cabochons, ornaments, and inexpensive jewelry; historically carved into seals and cameos. It has little industrial or construction use.

Geological facts

Carnelian is a variety of chalcedony rather than a separate mineral species. Color may darken with gentle heating or prolonged sunlight exposure.

Field identification & locations

Identify by its uniform warm color, fine-grained texture, translucency, and hardness; it should not scratch easily with a steel knife. A definitive ID may require testing because dyed agate, jasper, or colored glass can look similar.