mineral
Carnelian (Agate)
SiO2 (Silicon Dioxide with Iron Oxide inclusions)
Hardness: 6.5-7 on Mohs scale; Color: Reddish-orange to brownish-red; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline quartz); Cleavage: None, conchoidal fracture; Specific Gravity: 2.58-2.64.
- Hardness
- 6
- Color
- Reddish-orange to brownish-red
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 on Mohs scale; Color: Reddish-orange to brownish-red; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline quartz); Cleavage: None, conchoidal fracture; Specific Gravity: 2.58-2.64.
Formation & geological history
Forms in low-temperature hydrothermal environments, typically filling cavities within volcanic rock or sedimentary formations as silica-rich fluids precipitate over time.
Uses & applications
Widely used in lapidary art, jewelry (beads, cabochons, carvings), and as popular polished collector specimens.
Geological facts
Carnelian has been used in jewelry making for over 4,500 years, prized by ancient Sumerians, Egyptians, Romans, and Greeks for seals and amulets.
Field identification & locations
Identified by its warm translucent reddish-orange color and chalcedony texture. Found commonly in Brazil, India, Madagascar, and parts of the USA.
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