mineral

Carnelian Agate

Silicon Dioxide (SiO2)

Hardness: 6.5-7.0 (Mohs scale), Color: Red-orange to brownish-red, Luster: Vitreous to waxy, Structure: Trigonal (Cryptocrystalline), Cleavage: None, Specific Gravity: 2.58-2.64

Hardness: 6

Identified July 12, 2026More mineral →

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Physical properties

Hardness: 6.5-7.0 (Mohs scale), Color: Red-orange to brownish-red, Luster: Vitreous to waxy, Structure: Trigonal (Cryptocrystalline), Cleavage: None, Specific Gravity: 2.58-2.64

Formation & geological history

Formed in volcanic cavities or sedimentary environments through the deposition of silica-rich fluids. The reddish color is due to iron oxide impurities. Specimens can range from thousands to millions of years old.

Uses & applications

Widely used in jewelry (beads, cabochons, rings), seal stones, decorative carvings, and as a popular collector specimen for its vibrant color.

Geological facts

Carnelian was highly prized in ancient Egypt, where it was thought to assist spirits in their journey to the afterlife. It was also used extensively in Roman signet rings for sealing wax.

Field identification & locations

Identify by its translucency against light, waxy luster, and conchoidal fracture. Commonly found in Brazil, India, Uruguay, and the United States (Oregon/Washington). Collectors look for deep, uniform color.