Rock Identifier
Carnelian (Carnelian (SiO2) - Chalcedony variety) — mineral
mineral

Carnelian

Carnelian (SiO2) - Chalcedony variety

Hardness: 6.5-7 (Mohs scale), Color: Orange to reddish-brown, Luster: Vitreous to waxy, Crystal structure: Hexagonal (trigonal microcrystalline), Cleavage: None (conchoidal fracture), Specific gravity: 2.58-2.64

Hardness
6
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Physical properties

Hardness: 6.5-7 (Mohs scale), Color: Orange to reddish-brown, Luster: Vitreous to waxy, Crystal structure: Hexagonal (trigonal microcrystalline), Cleavage: None (conchoidal fracture), Specific gravity: 2.58-2.64

Formation & geological history

Forms when silica-rich groundwater percolates into cavities of volcanic rocks or sedimentary environments, acquiring its orange color from iron oxide impurities. Found in volcanic geodes and alluvial deposits.

Uses & applications

Primarily used in jewelry (cabochons, beads), decorative carvings, and as a popular collector's mineral. Historically used for seal stones and amulets.

Geological facts

Carnelian is a variety of chalcedony. In ancient Egypt, it was often buried with the dead to assist them in their journey to the afterlife. It was also a popular choice for signet rings because hot wax does not stick to it.

Field identification & locations

Identified by its distinctive orange-red translucency, waxy luster, and lack of banding (which distinguishes it from agate). It is commonly found in Brazil, India, Uruguay, Madagascar, and the United States.