gemstone

Tumbled carnelian

Carnelian, orange-red variety of cryptocrystalline chalcedony (SiO₂)

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; translucent orange to reddish-brown color, vitreous to waxy luster, microcrystalline quartz structure, and no visible cleavage. The rounded, polished surface indicates tumbling and may enhance its shine.

Identified August 9, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities or replaces material in volcanic rocks, with iron oxides producing the orange-red color. Deposits are geologically diverse and commonly associated with Cenozoic to older volcanic and sedimentary settings.

Uses & applications

Used for beads, cabochons, carvings, seals, and ornamental objects; durable enough for jewelry. Common tumbled pieces have modest collector value.

Geological facts

Carnelian is a chalcedony variety distinguished mainly by its warm orange-red coloration; heating can intensify or alter the color. It may visually resemble orange agate or glass.

Field identification & locations

Common sources include India, Brazil, Uruguay, Madagascar, and the United States. Identify it by its quartz-like hardness, translucency, waxy luster, and absence of bubbles or flow lines; the photograph alone cannot exclude dyed agate or glass.