mineral

Carnelian Agate

Chalcedony (SiO2 with Iron Oxide impurities)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale); Color: Orange, reddish-brown, brownish-red; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.64

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

Identified April 24, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Orange, reddish-brown, brownish-red; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.64

Formation & geological history

Formed through the deposition of silica in cavities within volcanic rocks. The red-orange hue is caused by iron oxide (hematite) impurities. It can be found in sedimentary environments and alluvial deposits.

Uses & applications

Used primarily in jewelry (cabochons, beads), decorative carvings, and as a semi-precious collector's mineral.

Geological facts

Carnelian was highly prized in ancient times; ancient Romans used it for signet rings and wax seals because the wax doesn't stick to the smooth surface of the stone.

Field identification & locations

Identified by its translucent to semi-opaque reddish-orange color and conchoidal fracture. Often found as rounded pebbles in stream beds or coastal areas in India, Brazil, and Uruguay.