gemstone

Tumbled carnelian

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

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent orange-red to reddish brown, with a vitreous-to-waxy luster and no visible cleavage. The smooth rounded surface indicates tumbling and polishing; internal cloudy bands or inclusions are typical.

Identified September 17, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when iron-bearing silica fills cavities and fractures in volcanic rocks, with iron oxides producing the red-orange color. Deposits range from ancient volcanic terrains to younger hydrothermal veins; the exact age cannot be determined from the image.

Uses & applications

Used for beads, cabochons, carvings, and ornamental objects; durable enough for jewelry and decorative stonework.

Geological facts

Carnelian is a variety of chalcedony and grades into sard, which is darker brown-red. Strongly uniform bright red-orange material may be heat-treated or dyed agate.

Field identification & locations

Identify it by its orange-red color, translucency, quartz hardness, and waxy polish; common sources include India, Brazil, Uruguay, Madagascar, and Germany. A scratch test should be avoided on finished pieces.