gemstone

Carnelian

Silicon dioxide (chalcedony variety), SiO2

Hardness of 6.5 to 7 on the Mohs scale, orange to reddish-orange color, vitreous to waxy luster, microcrystalline (cryptocrystalline) quartz crystal structure, conchoidal fracture with no true cleavage, specific gravity of 2.58 to 2.64.

Identified August 1, 2026More gemstone →

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Physical properties

Formation & geological history

Formed in silica-rich groundwater solutions depositing silica in cavities and fractures of pre-existing rocks, often in volcanic or sedimentary environments. Geological age varies greatly depending on the host rock, commonly associated with ancient volcanic flows.

Uses & applications

Widely used in jewelry, cabochons, beads, ornamental carvings, and talismans throughout history.

Geological facts

Carnelian has been prized since ancient times, used extensively in Ancient Egypt as a stone of protection and life, and frequently used for signet rings and intaglios in Roman and Greek cultures.

Field identification & locations

Identified in the field by its distinct translucent orange-to-red color, waxy luster, and conchoidal fracture. Found worldwide, with notable deposits in Brazil, India, Siberia, and the United States.

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