gemstone

Tumbled orange agate or carnelian

Microcrystalline quartz (chalcedony), SiO₂; orange coloration commonly from iron oxides

AI-generated identification · may be incorrect

Small polished/tumbled specimen with orange-red and cream banding or cloudy zoning, waxy to vitreous luster, and no obvious cleavage. Mohs hardness 6.5–7; specific gravity about 2.58–2.64; trigonal quartz structure.

Identified August 13, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and vesicles in volcanic rocks, depositing chalcedony in successive layers. Most specimens are geologically young relative to their host basalt, commonly Paleozoic to Cenozoic, though exact age requires provenance.

Uses & applications

Used for cabochons, beads, carvings, tumbling, ornaments, and inexpensive collectible specimens; occasionally used as a durable decorative stone.

Geological facts

Strong orange-red material is often marketed as carnelian, while visibly banded material is called orange agate; the boundary is informal. Color may be enhanced by heating or dyeing.

Field identification & locations

Identify by its waxy luster, fine-grained appearance, conchoidal fracture, hardness, and translucent orange banding; it should not scratch easily with a steel knife. Common sources include Brazil, Uruguay, India, Madagascar, and Botswana.