mineral
Carnelian
Carnelian (Cryptocrystalline Quartz, SiO2)
Hardness: 6.5-7 Mohs; Color: Orange, red, or brownish-red; Luster: Vitreous to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None; Specific gravity: 2.58-2.64
- Hardness
- 6
- Color
- Orange, red, or brownish-red
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 Mohs; Color: Orange, red, or 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, often filling cavities in volcanic rocks. Its color is derived from iron oxide impurities.
Uses & applications
Commonly used in jewelry (cabochons, beads), carvings, seals, and as decorative tumbled stones.
Geological facts
Ancient Romans used carnelian for signet rings because hot wax does not stick to it. It has been used in jewelry since the Neolithic period.
Field identification & locations
Identified by its distinctive translucency and orange hue. Found globally, with notable deposits in India, Brazil, Madagascar, and Uruguay.
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