Carnelian

Physical Properties

Hardness: 6.5-7 Mohs; Color: Reddish-orange to brownish-red; Luster: Vitreous to waxy; Crystal Structure: Trigonal/Microcrystalline; Cleavage: None; Specific Gravity: 2.58-2.64

Formation & Geological History

Formed in volcanic rocks at low temperatures when silica-rich groundwater percolates through cavities and veins. The red color is derived from iron oxide impurities. Found in geological formations ranging from the Precambrian to modern periods.

Uses & Applications

Primarily used in jewelry (beads, cabochons, cameos), seal stones for signet rings, ornamental carvings, and alternative healing collectibles.

Geological Facts

Ancient Romans used carnelian for seal rings because hot wax does not stick to it. It was also found in Egyptian tombs, representing the vibrant sun.

Field Identification & Locations

Identify by its translucent reddish-orange hue and waxy luster. Common locations include Brazil, India, Madagascar, and Uruguay. It lacks the banding seen in Agate, appearing more uniform or mottled.

Identified on: 5/2/2026

Mode: Standard