gemstone
Carnelian
Silicon Dioxide (SiO2) with iron oxide impurities
Hardness: 6.5-7 (Mohs); Color: Orange-red to brownish-red; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (cryptocrystalline); Specific Gravity: 2.58-2.64
- Hardness
- 6
- Color
- Orange-red to brownish-red
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 (Mohs); Color: Orange-red to brownish-red; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (cryptocrystalline); Specific Gravity: 2.58-2.64
Formation & geological history
Formed through the deposition of silica in gas cavities of volcanic rocks. The red-orange color is the result of iron oxide (hematite) impurities oxidized by heat.
Uses & applications
Primarily used in jewelry, lapidary art, beads, and as a popular collecting stone. Historically used for signet rings and seals because hot wax does not stick to it.
Geological facts
Carnelian has been used as a gemstone for over 4,500 years; it was highly prized by Ancient Egyptians who called it the 'setting sun.' It was found in the tombs of Sumerian kings.
Field identification & locations
Identify by its translucent, waxy appearance and uniform orange-to-red color without the distinct banding seen in banded agates. Found globally with major deposits in Brazil, India, and Uruguay.
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