Carnelian Agate

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.

Identified on: 4/24/2026

Mode: Standard