mineral

Carnelian

Carnelian Agate (Silica: SiO2)

Hardness: 6.5–7 (Mohs scale); Color: Orange to reddish-brown; Luster: Vitreous to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58–2.64.

Hardness: 6
Color: Orange to reddish-brown
Luster: Vitreous to waxy

Identified April 1, 2026More mineral →

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Physical properties

Hardness: 6.5–7 (Mohs scale); Color: Orange to reddish-brown; Luster: Vitreous to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58–2.64.

Formation & geological history

Formed through the deposition of silica from groundwater within the cavities of igneous rocks. The orange-red color is caused by iron oxide impurities. It can be found in volcanic rocks and sedimentary deposits spanning various geological eras.

Uses & applications

Primarily used as a semiprecious gemstone for jewelry, beads, cabochons, and seals. Historically used for intaglios and Roman signet rings.

Geological facts

Ancient Egyptians called carnelian 'the setting sun' or 'the sunset stone' and believed it had protective properties. It is one of the oldest gemstones used in bead-making, dating back to the 4th millennium BC.

Field identification & locations

Identify by its translucent quality, lack of visible crystalline structure, and waxy luster. Common in many river beds throughout the American West, Brazil, and India. Collectors should look for even color and translucency.