gemstone

Carnelian

SiO2 (Silicon Dioxide)

Hardness: 6.5-7 Mohs; Color: Pale orange to deep reddish-brown; Luster: Vitreous to waxy; Crystal structure: Hexagonal (trigonal); Cleavage: None; Specific gravity: 2.58-2.64

Hardness: 6
Color: Pale orange to deep reddish-brown
Luster: Vitreous to waxy

Identified July 5, 2026More gemstone →

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Physical properties

Hardness: 6.5-7 Mohs; Color: Pale orange to deep reddish-brown; Luster: Vitreous to waxy; Crystal structure: Hexagonal (trigonal); Cleavage: None; Specific gravity: 2.58-2.64

Formation & geological history

Formed primarily in volcanic environments through the infiltration of silica-rich fluids into cavities (amygdales) in igneous rocks. The orange color comes from iron oxide (hematite) impurities.

Uses & applications

Used extensively in jewelry (beads, cabochons), ornamental carvings, seals, and as a collector's specimen.

Geological facts

Carnelian was highly prized in ancient times. Ancient Romans used it for signet rings because hot wax does not stick to the stone. It has been found in archaeological sites dating back to the 4th millennium BC.

Field identification & locations

Identified by its distinctive translucency and even orange coloration. Commonly found in Brazil, India, Uruguay, and Madagascar. Tumbled specimens feel very smooth and have a waxy appearance.