mineral
Carnelian (Red Chalcedony)
Silicon Dioxide (SiO2) with iron oxide impurities
AI-generated identification · may be incorrectHardness: 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
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Physical properties
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
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.
