mineral

Carnelian Agate

Silicon Dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Translucent orange to reddish-brown; Luster: Waxy to vitreous; Crystal Structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture)

Hardness: 6
Color: Translucent orange to reddish-brown
Luster: Waxy to vitreous

Identified July 7, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Translucent orange to reddish-brown; Luster: Waxy to vitreous; Crystal Structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture)

Formation & geological history

Formed through the deposition of silica-rich groundwater in volcanic rock cavities (vesicles) or sedimentary layers. Its orange color is caused by iron oxide impurities.

Uses & applications

Commonly used in jewelry as cabochons, beads, and carvings. Historically used for signet rings and seals due to its resistance to wax sticking.

Geological facts

Carnelian was believed by ancient Romans and Egyptians to provide courage and protection. It is a variety of chalcedony.

Field identification & locations

Identify by its waxy luster, translucency, and warm orange-red hue. It is often found as nodules on beaches or in desert washes, particularly in India, Brazil, and Uruguay.