mineral

Carnelian (Red Chalcedony)

Silicon Dioxide (SiO2) with iron oxide impurities

Hardness: 6.5-7 (Mohs); Color: translucent orange to reddish-brown; Luster: waxy to vitreous; Crystal structure: Trigonal (cryptocrystalline); Cleavage: none; Specific gravity: 2.58–2.64

Hardness: 6
Color: translucent orange to reddish-brown
Luster: waxy to vitreous

Identified April 18, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: translucent orange to reddish-brown; Luster: waxy to vitreous; Crystal structure: Trigonal (cryptocrystalline); Cleavage: none; Specific gravity: 2.58–2.64

Formation & geological history

Formed in low-temperature hydrothermal environments where silica-rich fluids permeate cavities in volcanic rocks. The color comes from iron oxide (hematite) impurities.

Uses & applications

Used primarily in jewelry (cabochons, beads), decorative carvings, and seal stones. Highly valued in lapidary arts and as a collector's gemstone.

Geological facts

Carnelian was famously used in Ancient Egypt for amulets and scarabs, and it was used in Roman seal rings because hot wax does not stick to it.

Field identification & locations

Identified by its waxy luster and translucent orange-red glow when held to a light source. Found globally in Brazil, India, Madagascar, and Uruguay.

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