gemstone

Carnelian

SiO2 (Variety of Chalcedony/Quartz)

Hardness: 6.5 to 7 on the Mohs scale. Color: Orange to deep reddish-orange or brownish-red. Luster: Vitreous to waxy. Crystal structure: Trigonal (microcrystalline quartz/chalcedony). Cleavage: None (conchoidal fracture). Specific gravity: 2.58 to 2.64.

Hardness: 6
Color: Orange to deep reddish-orange or brownish-red
Luster: Vitreous to waxy

Identified July 29, 2026More gemstone →

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Physical properties

Formation & geological history

Formed in low-temperature hydrothermal environments, groundwater cavities, and volcanic vesicles through the deposition of silica from silica-rich solutions, often over millions of years.

Uses & applications

Widely used in jewelry making for beads, cabochons, rings, and historically for carved signet rings, intaglios, and talismans.

Geological facts

Carnelian has been prized as a gemstone since ancient times, used in ancient Rome, Greece, and Egypt where it was associated with Isis and placed in tombs to help the dead in their journey to the afterlife.

Field identification & locations

Can be identified in the field by its characteristic translucent reddish-orange color, waxy luster, and lack of cleavage with conchoidal fracture. Commonly found in Brazil, India, Madagascar, and the USA.