mineral

Carnelian

Carnelian (Red Chalcedony), SiO2 (Silicon Dioxide with iron oxide impurities)

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale. Color: Orange to reddish-brown. Luster: Vitreous to waxy. Crystal structure: Trigonal (microcrystalline/cryptocrystalline). Cleavage: None, exhibits conchoidal fracture. Specific gravity: 2.58-2.64.

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

Identified July 9, 2026More mineral →

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Physical properties

Formation & geological history

Primarily forms in volcanic environments where silica-rich groundwater fills cavities (vugs) in cooling lava. The reddish hue is caused by iron oxide impurities like hematite. It can also form in sedimentary environments through the deposition of silica in groundwater.

Uses & applications

Widely used in jewelry for cabochons and beads, as well as for decorative carvings, lapidary art, and historical use in signet rings and wax seals.

Geological facts

Ancient Egyptians called carnelian the 'setting sun' and believed it had protective properties. It was also one of the stones in the High Priest's Breastplate (the Hoshen) and is cited in numerous religious and historical texts.

Field identification & locations

Identified in the field by its translucent body, waxy luster, and distinctive orange color. Often found as pebbles in riverbeds or within basaltic host rocks. Commonly found in Brazil, India, Madagascar, and parts of the United States like Oregon and Washington.