gemstone

Tumbled carnelian

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

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; translucent orange-red to deep red, vitreous to waxy luster, very fine quartz fibers with no visible cleavage, and specific gravity about 2.60–2.65. The rounded, glossy surface indicates tumbling and polishing.

Identified August 13, 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-orange color; deposits range from ancient volcanic-hosted occurrences to younger sedimentary gravels. Common sources include India, Brazil, Uruguay, Madagascar, and Germany.

Uses & applications

Used for beads, cabochons, seals, carvings, and inexpensive jewelry; polished pieces are popular among mineral collectors and lapidaries.

Geological facts

Carnelian is part of the chalcedony family and may grade into orange agate. Strongly uniform color can sometimes indicate heat treatment or dyeing, though natural iron coloration is common.

Field identification & locations

Identify it by its warm red-orange color, translucency, quartz-like hardness, and lack of cleavage; it should resist scratching by steel but scratch glass. Common tumbled specimens typically sell for $2–$15; larger, vividly colored natural pieces may bring $20–$100+.