gemstone

Polished carnelian cabochon

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

AI-generated identification · may be incorrect

Smooth oval cabochon with reddish-brown translucent color and vitreous-to-waxy luster; quartz hardness 6.5–7 Mohs, no cleavage, cryptocrystalline structure, specific gravity about 2.60. The metal loop is jewelry hardware, not part of the specimen.

Identified August 16, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when iron-bearing silica-rich fluids deposit and color chalcedony, commonly in volcanic cavities and alluvial gravels. Carnelian deposits occur in India, Brazil, Uruguay, Madagascar, and elsewhere; the image alone cannot establish geological age or locality.

Uses & applications

Used for beads, pendants, cabochons, seals, and ornamental objects; common polished pieces generally have modest value.

Geological facts

Color ranges from orange to deep red-brown, with iron oxides producing the coloration. It may be confused with dyed agate or red glass; natural color often shows subtle translucency and uneven zoning.

Field identification & locations

Likely identified by its hardness, glassy/waxy luster, lack of bubbles, and ability to scratch ordinary glass. Near 10.5°N, 67°W in Venezuela, similar chalcedony and jasper may occur, but locality cannot be confirmed visually.