mineral

Carnelian Agate

Silicon Dioxide (SiO2)

Hardness: 6.5-7 Mohs; Color: Red-orange to brownish-red; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.64

Hardness: 6
Color: Red-orange to brownish-red
Luster: Vitreous to waxy

Identified June 3, 2026More mineral →

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Physical properties

Hardness: 6.5-7 Mohs; Color: Red-orange to brownish-red; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.64

Formation & geological history

Formed through the deposition of silica in cavities within volcanic rocks or sedimentary formations, often enriched with iron oxide which provides the red coloration.

Uses & applications

Primarily used as a gemstone in jewelry, beads, seals, and as decorative carvings for lapidary collectors.

Geological facts

Carnelian was used widely in the ancient world for signet rings and cylinder seals because hot wax does not stick to it. It has been used for ornamentation for over 4,500 years, with significant use in ancient Egypt.

Field identification & locations

Look for a translucent to semi-opaque reddish stone with smooth, waxy surfaces and curved fracture lines. It is commonly found in India, Brazil, Uruguay, and Madagascar.