gemstone

Tumbled carnelian (orange-red chalcedony)

Carnelian, a microcrystalline variety of quartz (SiO₂)

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; translucent orange to reddish-brown, typically waxy to vitreous luster, cryptocrystalline structure, and no visible cleavage. The rounded, polished form and internal color zoning are consistent with tumbled chalcedony.

Identified August 11, 2026More gemstone →

Explore Tumbled carnelian (orange-red chalcedony) in the encyclopedia →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater deposits chalcedony in volcanic cavities or fractures, with iron impurities producing the orange-red color; deposits range from Precambrian to recent. Common sources include India, Brazil, Uruguay, Madagascar, and Botswana.

Uses & applications

Used for beads, cabochons, carvings, ornamental objects, and inexpensive jewelry. It is durable but less valuable than transparent fine gemstones.

Geological facts

Carnelian is traditionally associated with vitality and has been used in seals and jewelry since antiquity, including ancient Egyptian and Roman artifacts.

Field identification & locations

Identify it by its hardness, waxy translucency, orange-red color, and lack of cleavage; it should not scratch easily with a steel blade. A magnifier may reveal cloudy color bands rather than quartz crystals.