gemstone

Tumbled carnelian

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

AI-generated identification · may be incorrect

Typically Mohs 6.5–7; translucent reddish-orange to brown, with a vitreous-to-waxy luster and no visible cleavage. It has a cryptocrystalline quartz structure and specific gravity around 2.60–2.65.

Identified August 16, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures in volcanic rocks, often gaining its red color from iron oxides. Deposits range from ancient volcanic terrains to younger sedimentary-hosted occurrences.

Uses & applications

Used for beads, cabochons, carvings, ornaments, and inexpensive jewelry; polished pieces are popular lapidary and collecting materials.

Geological facts

Carnelian is a variety of chalcedony and may overlap visually with red jasper or heat-treated agate. Its warm color was prized in ancient Egypt, Rome, and Mesopotamia for seals and amulets.

Field identification & locations

Identify it by its smooth tumbled form, translucent orange-red body color, glassy/waxy surface, and hardness sufficient to scratch glass. Common sources include India, Brazil, Uruguay, Madagascar, and Germany.