mineral

Carnelian (Red Chalcedony)

Silicon Dioxide (SiO2) with iron oxide impurities

Hardness: 6.5-7 on Mohs scale; Color: semi-translucent reddish-orange to brownish-red; Luster: vitreous to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58–2.64

Hardness: 6
Color: semi-translucent reddish-orange to brownish-red
Luster: vitreous to waxy

Identified March 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica from groundwater in the cavities of igneous rocks or through sedimentary replacement. Can occur in rocks of various geological ages from Precambrian to Cenozoic.

Uses & applications

Primary use is in jewelry (beads, cabochons, translucent carvings), lapidary art, and as a semi-precious collector's gemstone. Historically used for seals and signet rings because hot wax does not stick to it.

Geological facts

Ancient Egyptians referred to carnelian as 'the setting sun.' It was one of the first gemstones used by humans, appearing in decorative artifacts as early as the 4th millennium BC in Bulgaria and the Indus Valley.

Field identification & locations

Identify in the field by its distinctive orange-red translucency and smooth, shell-like (conchoidal) fracture surface. Common locations include Brazil, India, Uruguay, and various riverbeds in the Pacific Northwest, USA. Collectors should look for rich, uniform color and high translucency.

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