gemstone

Tumbled carnelian agate

Cryptocrystalline quartz (chalcedony), SiO₂; iron-bearing orange-red variety

AI-generated identification · may be incorrect

Typically translucent orange, red, brown, and gray with waxy-to-glassy luster, no visible crystal faces, and conchoidal fracture; Mohs hardness 6.5–7, specific gravity about 2.6. The rounded shape indicates mechanical tumbling and polishing.

Identified September 17, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures in volcanic rocks, with iron impurities producing the orange-red color; commonly associated with Cenozoic to older volcanic deposits. Exact age cannot be determined from the image.

Uses & applications

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

Geological facts

Banding or translucent zones may indicate agate rather than uniformly colored carnelian; strong flashlight illumination can reveal internal patterns. The specimen may also be marketed broadly as “orange agate.”

Field identification & locations

Common sources include Brazil, Uruguay, India, Madagascar, Botswana, and the United States. Field identification relies on hardness, waxy luster, translucency, conchoidal fracture, and resistance to scratching by steel.