gemstone

Tumbled carnelian

Carnelian, a red-orange variety of chalcedony (microcrystalline quartz, SiO₂)

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; reddish-brown to orange, translucent at edges, with a waxy to vitreous luster and no visible cleavage. Its cryptocrystalline quartz structure commonly shows subtle internal clouding or banding.

Identified August 9, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures, with iron oxides producing the red color; most deposits are Cenozoic to older volcanic or sedimentary-hosted material. This specimen appears polished or tumbled.

Uses & applications

Used for beads, cabochons, carvings, ornamental objects, and inexpensive jewelry; historically used for seals and signet rings.

Geological facts

Carnelian is an agate-family chalcedony; heating can intensify its orange-red color. It may be confused with dyed agate or red jasper.

Field identification & locations

Commonly found in Brazil, India, Uruguay, Madagascar, Germany, and the United States. Identify it by its orange-red translucency, quartz-like hardness, smooth conchoidal fracture, and lack of cleavage; a scratch test should be avoided on finished pieces.