mineral

Carnelian Agate

Silicon Dioxide (SiO2) - variety of Chalcedony

Hardness: 6.5-7 (Mohs scale), Color: Reddish-orange to brownish-red, Luster: Vitreous to waxy, Crystal Structure: Hexagonal (trigonal) microcrystalline, Cleavage: None, Specific Gravity: 2.58-2.64

Hardness: 6

Identified April 25, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs scale), Color: Reddish-orange to brownish-red, Luster: Vitreous to waxy, Crystal Structure: Hexagonal (trigonal) microcrystalline, Cleavage: None, Specific Gravity: 2.58-2.64

Formation & geological history

Formed through the deposition of silica in the cavities of volcanic rocks (vugs) as groundwater leaches minerals. Its reddish color comes from iron oxide (hematite) impurities.

Uses & applications

Used primarily in jewelry as cabochons, beads, and carvings. Historically used for signet rings and wax seals because hot wax does not stick to it.

Geological facts

Carnelian was highly prized by the ancient Egyptians as the 'setting sun' and was used in the funerary mask of Tutankhamun. It was believed to provide courage in battle.

Field identification & locations

Identify by its translucent to semi-opaque waxy appearance and orange color. Common locations include Brazil, India, Uruguay, Madagascar, and the USA (Pacific Northwest).

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