gemstone

Tumbled carnelian (reddish chalcedony)

Carnelian, a cryptocrystalline variety of quartz (SiO₂)

AI-generated identification · may be incorrect

Typically Mohs hardness 6.5–7, translucent orange-red to brown, with vitreous-to-waxy luster and no visible crystal faces or cleavage. The smooth rounded surface indicates tumbling or polishing; reddish color comes mainly from iron oxides.

Identified August 10, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures, depositing microcrystalline quartz; iron impurities produce the red-orange coloration. Deposits occur in volcanic and sedimentary environments, generally of varied Phanerozoic age.

Uses & applications

Used for beads, cabochons, carvings, seals, and ornamental objects; durable enough for jewelry and small decorative pieces.

Geological facts

Carnelian belongs to the broader chalcedony family, which includes agate and jasper. Ancient Egyptians, Greeks, Romans, and Near Eastern cultures used it extensively for seals and amulets.

Field identification & locations

Identify it by its uniform warm red-orange color, translucency at thin edges, waxy luster, and hardness sufficient to scratch glass; glass imitations may show bubbles or overly uniform color. Common sources include India, Brazil, Uruguay, Madagascar, and Germany.