gemstone

Tumbled orange chalcedony (likely carnelian)

Carnelian, a microcrystalline quartz variety; SiO₂, commonly colored by iron oxides

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent orange to reddish-orange, vitreous to waxy luster, cryptocrystalline structure, no visible cleavage, specific gravity about 2.60–2.65. The rounded, glossy form indicates tumbling and polishing.

Identified August 26, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures in volcanic rocks, with iron producing the orange color; deposits range from Precambrian to younger volcanic-hosted formations.

Uses & applications

Used for cabochons, beads, carvings, and inexpensive jewelry; also collected as a polished ornamental stone.

Geological facts

Carnelian is a color variety of chalcedony rather than a separate mineral species; heating can intensify its orange-red color by oxidizing iron.

Field identification & locations

Identify by its even translucent orange color, waxy appearance, lack of cleavage, and quartz-level hardness; common sources include India, Brazil, Uruguay, Madagascar, and Germany. A scratch test should be avoided on finished pieces.