mineral
Carnelian Agate
Silicon dioxide (SiO2) with iron oxide impurities
Hardness: 6.5-7 (Mohs); Color: Waxy reddish-brown to orange; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (trigonal) microcrystalline silica; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.64
- Hardness
- 6
- Color
- Waxy reddish-brown to orange
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 (Mohs); Color: Waxy reddish-brown to orange; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (trigonal) microcrystalline silica; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.64
Formation & geological history
Formed in volcanic and sedimentary rocks as groundwater rich in silica precipitates in cavities. The distinctive orange-red color is caused by iron oxide (hematite) inclusions.
Uses & applications
Primarily used in jewelry for beads, cabochons, and intaglios. Also highly valued in spiritual and decorative lapidary arts.
Geological facts
Carnelian was used by ancient Egyptians for amulets and by Romans for signet rings because hot wax does not stick to it. It has been a prized gemstone for over 4,500 years.
Field identification & locations
Identified by its waxy luster, translucency, and warm color range. Commonly found in Brazil, India, Uruguay, and Madagascar. Collectors look for uniform color and high translucency.
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