sedimentary

Carnelian Agate

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale); Color: Translucent orange-red to brownish-red; Luster: Waxy to vitreous; Crystal Structure: Trigonal/Hexagonal (Microscopic); Cleavage: None/Conchoidal fracture; Specific Gravity: 2.58-2.64

Hardness: 6
Color: Translucent orange-red to brownish-red
Luster: Waxy to vitreous

Identified July 6, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in volcanic cavities or sedimentary environments where silica-rich fluids deposit layers of chalcedony. The reddish hue is caused by iron oxide (limonite or hematite) impurities trapped during formation.

Uses & applications

Used primarily in lapidary arts for cabochons, beads, and carvings. Historically used for signet rings and cylinders due to its ability to release wax cleanly.

Geological facts

Ancient Egyptians referred to carnelian as 'the setting sun.' It was thought to lend courage to the wearer and protect against the evil eye.

Field identification & locations

Identify in the field by its waxy texture and translucency when held to light. Common in riverbeds and gravel deposits, particularly in India, Brazil, and Uruguay.