mineral

Tumbled carnelian

Carnelian, orange-red chalcedony (microcrystalline quartz, SiO₂)

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; translucent to opaque orange-red, with vitreous to waxy luster and no visible cleavage. Its color commonly comes from iron-oxide inclusions; the smooth shape indicates tumbling and polishing.

Identified September 22, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures, later becoming cryptocrystalline quartz; iron produces the orange hue. Deposits occur in volcanic and sedimentary environments, generally ranging from Paleozoic to Cenozoic in age.

Uses & applications

Used for beads, cabochons, carvings, ornaments, and inexpensive jewelry; polished pieces are popular among collectors.

Geological facts

Carnelian is a variety of chalcedony closely related to sard, with color grading from yellow-orange to deep reddish brown. Ancient Egyptians and Romans used it for seals, amulets, and engraved gems.

Field identification & locations

Identify it by its uniform orange-red color, fine texture, lack of cleavage, and ability to scratch glass; dye-treated agate can resemble it but often shows banding. Common sources include India, Brazil, Uruguay, Madagascar, and Germany.