gemstone

Tumbled carnelian agate

Cryptocrystalline quartz (SiO₂), chalcedony variety colored by iron oxides

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent orange-brown to reddish-brown, with vitreous/waxy luster and no visible cleavage. Its rounded, polished surface and subtle cloudy/banded texture are typical of tumbled chalcedony.

Identified August 30, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities in volcanic rocks; iron impurities create the red-orange color. Most deposits are Cenozoic to older, commonly associated with basaltic lava flows.

Uses & applications

Used for cabochons, beads, carvings, and inexpensive jewelry; polished pieces are popular lapidary and collector specimens.

Geological facts

Carnelian is a variety of chalcedony, and heating can intensify its red-orange color. The specimen appears wet, which enhances translucency and luster.

Field identification & locations

Common sources include Brazil, Uruguay, India, Madagascar, and the United States. Identification is supported by hardness, waxy translucency, lack of cleavage, and orange-red coloration; definitive testing requires gemological examination.