mineral
Carnelian
Carnelian (SiO2) - Chalcedony variety
AI-generated identification · may be incorrectHardness: 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.
