gemstone

Carnelian (orange chalcedony)

Chalcedony, microcrystalline quartz (SiO₂), iron-colored variety

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent orange to reddish-brown, waxy to vitreous luster, cryptocrystalline structure, no visible cleavage, conchoidal fracture; specific gravity about 2.6.

Identified August 10, 2026More gemstone →

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Physical properties

Hardness 6.5–7 Mohs; translucent orange to reddish-brown, waxy to vitreous luster, cryptocrystalline structure, no visible cleavage, conchoidal fracture; specific gravity about 2.6.

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures in volcanic rocks, with iron oxides producing the orange-red color. Deposits range from ancient volcanic terrains to younger sedimentary environments.

Uses & applications

Used for beads, cabochons, carvings, seals, and ornamental objects; attractive translucent pieces commonly have modest collector value.

Geological facts

Carnelian is a variety of chalcedony rather than a separate mineral species; deeper red-orange color is generally more prized, and heating or dyeing may enhance coloration.

Field identification & locations

Identify by its orange translucent body, waxy luster, very fine texture, and lack of cleavage; it commonly occurs in basaltic cavities and alluvial gravels in India, Brazil, Uruguay, Madagascar, and the United States. A scratch test should not be attempted on the specimen.