sedimentary
Carnelian Agate
Silicon Dioxide (SiO2) - variety of Chalcedony
Hardness: 6.5-7 (Mohs scale), Color: semi-transparent orange to reddish-brown, Luster: waxy to vitreous, Crystal Structure: Cryptocrystalline, Fracture: Conchoidal
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs scale), Color: semi-transparent orange to reddish-brown, Luster: waxy to vitreous, Crystal Structure: Cryptocrystalline, Fracture: Conchoidal
Formation & geological history
Formed as a secondary mineral in volcanic cavities or sedimentary environments by the deposition of silica from groundwater; often found as water-worn pebbles on beaches.
Uses & applications
Commonly used in jewelry, lapidary arts for cabochons and beads, and historically used for signet rings and wax seals.
Geological facts
Carnelian has been used as a gemstone since prehistoric times, appearing in ancient Egyptian tombs and Roman signet rings. Its orange color comes from iron oxide impurities.
Field identification & locations
Identify by its waxy texture, translucency, and warm orange hue. Usually found on beaches or in gravel beds where volcanic rocks have eroded.
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