gemstone

Polished carnelian agate

Microcrystalline quartz (SiO₂), chalcedony variety with iron-oxide coloration

AI-generated identification · may be incorrect

Typically Mohs hardness 6.5–7, vitreous to waxy luster, orange-red translucent body with pale quartz/chalcedony banding; no visible cleavage and conchoidal fracture. The pictured piece appears tumbled and polished.

Identified September 7, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities in volcanic rock, depositing layered chalcedony; iron oxides create the orange-red color. Agates commonly formed in Cenozoic to older volcanic environments, though exact age requires locality information.

Uses & applications

Used for cabochons, beads, carvings, seals, and inexpensive ornamental objects; durable enough for jewelry and display specimens.

Geological facts

Carnelian is the reddish-orange variety of chalcedony, while the visible internal banding makes this specifically an agate or carnelian agate. Color may be natural or enhanced by heat/dyeing.

Field identification & locations

Identify by hardness, translucency, waxy polish, conchoidal fracture, and curved banding; common sources include Brazil, Uruguay, India, Madagascar, and the United States. Avoid confusing it with dyed glass or resin.