mineral

Carnelian

Carnelian (Silicon Dioxide, SiO2)

Hardness: 6.5-7.0 (Mohs scale); Color: Orangish-red to brownish-red; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.64.

Hardness: 6
Color: Orangish-red to brownish-red
Luster: Vitreous to waxy

Identified April 14, 2026More mineral →

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Physical properties

Hardness: 6.5-7.0 (Mohs scale); Color: Orangish-red to brownish-red; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.64.

Formation & geological history

Formed in low-temperature hydrothermal environments where silica-rich fluids deposit in cavities of volcanic rocks (basalt/rhyolite) or sedimentary formations. Color is derived from iron oxide (hematite) impurities.

Uses & applications

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

Geological facts

Carnelian has been used as a gemstone for over 4,500 years; Ancient Egyptians called it 'the setting sun' and used it in amulets for protection. It was also commonly used for signet rings because hot wax does not stick to it.

Field identification & locations

Identify by its translucent reddish-orange color and conchoidal fracture. Often found in riverbeds or volcanic deposits in Brazil, India, Madagascar, and Uruguay. Look for stones that glow when held to the light.