gemstone

Carnelian

Orange-red chalcedony (microcrystalline quartz, SiO₂)

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent orange to red-brown, vitreous to waxy luster, cryptocrystalline structure, no cleavage, and specific gravity about 2.60–2.65. The rounded, polished appearance suggests a tumbled stone.

Identified August 23, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures, often in volcanic rocks; iron impurities create the orange-red color. Deposits range from Paleozoic to Cenozoic, with age varying by locality.

Uses & applications

Used for beads, cabochons, carvings, seals, and ornamental objects; durable enough for jewelry and minor decorative construction inlays. Common specimens have modest collector value.

Geological facts

Carnelian is a red-orange variety of chalcedony and may be naturally colored or heat-treated to intensify its hue. Ancient Egyptians and Romans used it for amulets, signet rings, and carved gems.

Field identification & locations

Commonly found in volcanic terrains and alluvial gravels, especially in India, Brazil, Uruguay, Madagascar, and Germany. Identify it by its even warm color, translucency, lack of visible crystal faces, and ability to scratch glass; test cautiously because coatings and glass imitations exist.