mineral

Polished carnelian agate

Chalcedony, microcrystalline SiO₂; the reddish variety is commonly called carnelian

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; glossy, translucent reddish-brown body with cream-colored mineral or host-rock inclusions. It has a trigonal microcrystalline quartz structure and no visible cleavage; exact identification is uncertain from the photo.

Identified October 11, 2026More mineral →

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Physical properties

Formation & geological history

Silica-rich fluids deposited microscopic quartz in cavities or fractures, later colored red-orange by iron oxides. Such agate forms in volcanic rocks over geologic time; the specimen’s specific age and locality cannot be determined visually.

Uses & applications

Used for beads, cabochons, carvings, and ornamental objects; polished pieces are popular with collectors.

Geological facts

Carnelian has been used for seals and jewelry since antiquity. The pale patches may be inclusions or attached matrix rather than a distinct crystal.

Field identification & locations

Look for waxy luster, translucence at thin edges, and red-orange color; agate commonly occurs in volcanic cavities worldwide, including Brazil, India, and Uruguay. This appears to be a shaped, polished specimen.