gemstone

Tumbled carnelian/chalcedony

Carnelian, a microcrystalline variety of quartz (SiO₂), usually colored by iron oxides

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; orange to reddish-brown, translucent to opaque, with a waxy to vitreous luster and no visible cleavage. The rounded, polished surface and cloudy color zoning are typical of tumbled chalcedony.

Identified September 7, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich fluids fill cavities and fractures, with iron impurities producing orange-red coloration; deposits are commonly Cenozoic to older. Heat treatment may intensify the color.

Uses & applications

Used for beads, cabochons, carvings, ornaments, and inexpensive jewelry; historically used for seals and amulets.

Geological facts

Carnelian belongs to the quartz family and grades into orange chalcedony and sard; its color can darken or brighten after heating.

Field identification & locations

Identify it by its smooth waxy polish, hardness, conchoidal fracture, and translucent orange body; common sources include India, Brazil, Uruguay, Madagascar, and Germany.