gemstone

Tumbled carnelian

Carnelian, a red-orange variety of chalcedony (microcrystalline quartz, SiO₂)

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; translucent orange to reddish-brown color, vitreous-to-waxy luster, cryptocrystalline structure, and no visible cleavage. The rounded shape indicates mechanical tumbling and polishing.

Identified September 7, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when iron impurities color silica-rich chalcedony, commonly filling cavities and fractures in volcanic rocks; deposits range from ancient to recent geological ages. The pictured pieces are processed specimens rather than natural crystal faces.

Uses & applications

Used for beads, cabochons, carvings, jewelry, and ornamental objects; small tumbled pieces are common collectors’ and lapidary material.

Geological facts

Carnelian’s color can deepen with heating or prolonged sunlight exposure. It belongs to the broader agate/chalcedony family and was widely used for ancient seals and amulets.

Field identification & locations

Identify by orange-red translucency, smooth polish, lack of cleavage, and quartz-like hardness; glass imitations may show bubbles and scratch more easily. Common sources include India, Brazil, Uruguay, Madagascar, and Germany.