mineral

Carnelian

Carnelian (SiO2)

Hardness: 6.5-7 Mohs; Color: Brownish-red to translucent orange; Luster: Vitreous to waxy; Crystal Structure: Trigonal (cryptocrystalline chalcedony); Cleavage: None; Specific Gravity: 2.58-2.64

Hardness: 6
Color: Brownish-red to translucent orange
Luster: Vitreous to waxy

Identified June 18, 2026More mineral →

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Physical properties

Hardness: 6.5-7 Mohs; Color: Brownish-red to translucent orange; Luster: Vitreous to waxy; Crystal Structure: Trigonal (cryptocrystalline chalcedony); Cleavage: None; Specific Gravity: 2.58-2.64

Formation & geological history

Formed by the precipitation of silica from groundwater into cavities of igneous rocks such as basalt. The reddish-orange color comes from iron oxide (hematite) impurities.

Uses & applications

Primarily used in jewelry (beads, cabochons), ornamental carvings, seals, and as a popular collector's gemstone.

Geological facts

Carnelian was highly valued in Ancient Egypt, where it was buried with the dead to assist in the afterlife journey. It was also widely used for signet rings in the Roman Empire because hot wax does not stick to it.

Field identification & locations

Identify in the field by its waxy luster and translucent orange-red hue when held against light. Found globally with high-quality deposits in Brazil, India, Uruguay, and Madagascar.