sedimentary
Chalcedony (Carnelian Agate)
Cryptocrystalline quartz (SiO2) with Iron Oxide inclusions
Hardness: 6.5-7 (Mohs); Color: Waxy white to orange-red; Luster: Vitreous to waxy; Structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.64
- Hardness
- 6
- Color
- Waxy white to orange-red
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 (Mohs); Color: Waxy white to orange-red; Luster: Vitreous to waxy; Structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.64
Formation & geological history
Formed from silica-rich groundwater precipitating in cavities or fissures of volcanic or sedimentary rocks over millions of years, often colored by iron oxides during deposition.
Uses & applications
Used primarily in lapidary work, jewelry (beads and cabochons), decorative carvings, and as a popular metaphysical or collector stone.
Geological facts
The name carnelian comes from the Latin word 'cornum' (cherry), referring to its red color. It was highly prized in ancient Rome and Egypt for signet rings and amulets.
Field identification & locations
Identify by its waxy luster, translucency, and lack of visible crystal grains. Often found in riverbeds or gravel deposits. Distinguished from jasper by its translucency.
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