mineral
Carnelian (Red Agate)
Carnelian (SiO2 with Hematite inclusions)
Hardness: 6.5-7 Mohs; Color: Orange-red to brownish-red; Luster: Vitreous to waxy; Structure: Hexagonal (trigonal) - cryptocrystalline; Cleavage: None; SG: 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; Structure: Hexagonal (trigonal) - cryptocrystalline; Cleavage: None; SG: 2.58-2.64
Formation & geological history
Formed in volcanic and sedimentary rocks as a secondary mineral in geodes or cavities. The color is derived from iron oxide (hematite) impurities. Most commercial specimens are from the Neogene to present.
Uses & applications
Extensively used in lapidary arts, jewelry (cabochons, beads), seal stones, and decorative carvings. It is a traditional birthstone for Virgo.
Geological facts
Carnelian was used by ancient Egyptians for amulets and seals, as they believed it offered protection. It was also popular in Roman signet rings because hot wax does not stick to it.
Field identification & locations
Identify by its characteristic translucency combined with its distinct orange-red hue. It is commonly found in Brazil, India, Uruguay, and Madagascar. Collectors should look for uniform color and lack of heavy surface cracking.
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