gemstone

Polished carnelian agate

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

AI-generated identification · may be incorrect

Typically Mohs 6.5–7; translucent reddish-orange with a vitreous to waxy luster and no visible cleavage. The piece appears cut and polished, though its exact identification cannot be confirmed from the image alone.

Identified September 26, 2026More gemstone →

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Physical properties

Formation & geological history

Silica-rich fluids deposited microscopic quartz in cavities and fractures; iron oxides impart the color. Agates form in volcanic and other host rocks across many geological ages.

Uses & applications

Used for beads, cabochons, carvings, and decorative objects; historically valued for seals and amulets.

Geological facts

Carnelian is colored chiefly by iron impurities and may be heat-treated to deepen its red-orange hue.

Field identification & locations

Look for a hard, glassy-waxy surface, translucency at the edges, and possible banding; common sources include Brazil, India, Uruguay, and Madagascar. Similar red agate varieties can be difficult to distinguish visually.