Rock Identifier
Red cabochon gemstone, likely carnelian (Carnelian: orange-red chalcedony, microcrystalline quartz (SiO₂)) — gemstone
gemstone

Red cabochon gemstone, likely carnelian

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

AI-generated identification · may be incorrect

Translucent wine-red cabochon with a vitreous-to-waxy luster and no visible cleavage; quartz hardness is about 7 Mohs, specific gravity 2.58–2.64. The smooth domed cut and band setting indicate a polished gemstone rather than a raw rock.

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Physical properties

Translucent wine-red cabochon with a vitreous-to-waxy luster and no visible cleavage; quartz hardness is about 7 Mohs, specific gravity 2.58–2.64. The smooth domed cut and band setting indicate a polished gemstone rather than a raw rock.

Formation & geological history

Carnelian forms when iron impurities color chalcedony in silica-rich volcanic cavities, veins, or alluvial deposits; it is commonly Cenozoic to older, depending on the host deposit. Exact identification is uncertain from the photograph, and similar stones include red jasper, dyed agate, and ruby glass.

Uses & applications

Used in rings, beads, seals, carvings, and decorative objects. Common-quality cabochons are valued primarily for color, translucency, and workmanship.

Geological facts

Carnelian’s red color comes mainly from iron oxides; heating can intensify or alter the color. It is traditionally associated with signet rings and ancient Egyptian and Roman jewelry.

Field identification & locations

Look for even red-orange color, slight translucency at the edges, and quartz-like hardness; glass bubbles or scratches would suggest imitation. Common sources include India, Brazil, Uruguay, Madagascar, and Germany.