gemstone

Tumbled carnelian

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

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; orange-red to brown-red, translucent to opaque, with a waxy to vitreous luster and no visible cleavage. The smooth rounded surface indicates tumbling and polishing; faint internal banding or cloudy zones are typical.

Identified September 17, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when iron impurities color silica-rich chalcedony, commonly filling cavities and fractures in volcanic rocks. Deposits occur mainly in India, Brazil, Uruguay, Madagascar, and parts of the United States; ages range from relatively young volcanic-hosted material to ancient sedimentary occurrences.

Uses & applications

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

Geological facts

Carnelian is closely related to sard, with color determined largely by iron oxidation. Heating can intensify its orange-red color, and dyed chalcedony is also sold commercially.

Field identification & locations

Identify it by its warm orange-red color, fine-grained texture, lack of cleavage, glass scratch resistance, and typically even waxy appearance; it should not show large quartz crystals. Common tumbled specimens are usually worth $2–$15 USD; fine natural, vividly colored pieces may bring $20–$100+.