mineral
Carnelian
Carnelian (Silicon Dioxide - SiO2)
AI-generated identification · may be incorrectHardness: 6.5–7 on Mohs scale; Color: Reddish-brown to orange; Luster: Vitreous to waxy; Crystal structure: Hexagonal (trigonal), microcrystalline; Cleavage: None; Specific gravity: 2.58–2.64
- Hardness
- 6
- Color
- Reddish-brown to orange
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5–7 on Mohs scale; Color: Reddish-brown to orange; Luster: Vitreous to waxy; Crystal structure: Hexagonal (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. The red color is caused by impurities of iron oxide (hematite).
Uses & applications
Predominantly used for jewelry, lapidary arts, and ornamental carvings. Historically used for seals and signet rings because hot wax does not stick to it.
Geological facts
Carnelian was highly prized in ancient Egypt, where it was thought to provide protection and courage. It was used in many of the artifacts found in Tutankhamun's tomb.
Field identification & locations
Identify by its translucency and uniform reddish-orange color. It is common in India, Brazil, Uruguay, and Madagascar. In the field, look for volcanic host rocks and use a hardness test to distinguish from plastic or glass.
