gemstone

Carnelian

SiO2 (Variety of Chalcedony)

Hardness of 6.5 to 7 on the Mohs scale, color ranges from orange to reddish-orange to brown, waxy to vitreous luster, trigonal crystal system with microcrystalline structure, conchoidal fracture with no cleavage, specific gravity of 2.58 to 2.64.

Identified August 3, 2026More gemstone →

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Physical properties

Formation & geological history

Forms in silica-rich groundwater filling cavities in volcanic or sedimentary rocks, often precipitated from low-temperature aqueous solutions.

Uses & applications

Used widely in jewelry, beads, intaglios, and cameo carvings since ancient times.

Geological facts

Carnelian was highly prized in ancient Egypt, where it was often placed in tombs to assist the dead in their journey to the afterlife, and it was frequently used for signet rings in the Roman era.

Field identification & locations

Easily identified in the field by its distinct orange-to-red color, waxy luster, and conchoidal fracture. Commonly found in India, Brazil, Uruguay, and the United States.