gemstone

Tumbled carnelian or orange chalcedony

Chalcedony, microcrystalline quartz (SiO₂), iron-colored variety

AI-generated identification · may be incorrect

Typically Mohs hardness 6.5–7, translucent orange to reddish-brown, with waxy to vitreous luster and no visible cleavage; composed of intergrown quartz fibers. The rounded, glossy shape indicates tumbling or polishing, and surface bubbles may indicate a coating or glassy imitation.

Identified August 23, 2026More gemstone →

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Physical properties

Formation & geological history

Natural chalcedony forms when silica-rich groundwater fills cavities and fractures, commonly in volcanic rocks; iron oxides produce the orange-red color. Deposits range from ancient to recent and occur worldwide.

Uses & applications

Used for beads, cabochons, carvings, and inexpensive collector specimens; historically used for seals and ornamental objects. Common pieces generally have modest commercial value.

Geological facts

Carnelian is the orange-red variety of chalcedony, while paler orange material is often called orange chalcedony. Heat treatment can intensify its red color.

Field identification & locations

Identify it by its fine, uniform texture, translucency, hardness, and lack of cleavage; natural specimens usually show color banding or cloudy zones. Common sources include India, Brazil, Uruguay, Madagascar, and the United States.