gemstone

Red cabochon gemstone, likely carnelian or red agate

Cryptocrystalline quartz (chalcedony), SiO₂

AI-generated identification · may be incorrect

Smooth oval cabochon with reddish-brown color, waxy to glassy luster, and no visible crystal faces; hardness about 6.5–7 Mohs, specific gravity roughly 2.6. The setting appears to be a metal ring, and the stone may be polished or possibly dyed.

Identified September 13, 2026More gemstone →

Explore Red cabochon gemstone, likely carnelian or red agate in the encyclopedia →

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Physical properties

Formation & geological history

Carnelian and red agate form when silica-rich groundwater fills cavities and fractures in volcanic rocks, commonly during the Cenozoic to older volcanic episodes. Iron impurities produce the red-to-brown color.

Uses & applications

Used for rings, beads, cabochons, carvings, and ornamental objects; generally affordable jewelry material.

Geological facts

Carnelian is the more uniformly translucent red variety, while agate commonly shows banding or cloudy color zones. The photograph does not reveal banding, translucency, or treatment conclusively.

Field identification & locations

Look for chalcedony’s fine-grained texture, curved fracture, hardness, and lack of cleavage; glass and dyed composites are common imitations. Common sources include Brazil, India, Uruguay, Madagascar, and Germany.