mineral
Carnelian
Carnelian (Cryptocrystalline Quartz, SiO2)
Hardness: 6.5-7 on Mohs scale; Color: Orange, red, brownish-red; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific Gravity: 2.58-2.64
- Hardness
- 6
- Color
- Orange, red, brownish-red
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 on Mohs scale; Color: Orange, red, brownish-red; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific Gravity: 2.58-2.64
Formation & geological history
Found in sedimentary rocks but forms primarily in volcanic cavities or from groundwater depositing silica over millions of years. The color is caused by iron oxide (limonite or hematite) impurities.
Uses & applications
Used extensively in jewelry (beads, cabochons, signet rings), carved figurines, and decorative polished spheres. Historically used for wax seals because hot wax does not stick to it.
Geological facts
Ancient Egyptians called carnelian the 'setting sun' and believed it had protective properties. It was one of the stones in the High Priest's Breastplate mentioned in the Bible.
Field identification & locations
Identify by its translucent to semi-opaque orange hue and waxy luster. In the field, look for river-worn nodules with a dull exterior but bright interior when fractured. Common in Brazil, India, and Uruguay.
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