mineral
Carnelian Agate
Silicon Dioxide (SiO2) with Hematite impurities
Hardness: 6.5-7 on Mohs scale; Color: Red-orange to brownish-red and white; Luster: Waxy to vitreous; Crystal structure: Trigonal (cryptocrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.64.
- Hardness
- 6
- Color
- Red-orange to brownish-red and white
- Luster
- Waxy to vitreous
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Physical properties
Hardness: 6.5-7 on Mohs scale; Color: Red-orange to brownish-red and white; Luster: Waxy to vitreous; Crystal structure: Trigonal (cryptocrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.64.
Formation & geological history
Formed in cavities of volcanic rock when silica-rich water precipitates. The red-orange color is a result of iron oxide (hematite) impurities coloring the chalcedony.
Uses & applications
Commonly used in jewelry, decorative carvings, beads, and as talismans or tumbled stones for collectors.
Geological facts
Carnelian has been used for over 4,500 years; Ancient Romans used it for signet rings as hot wax does not stick to it. It was also highly valued in ancient Egypt.
Field identification & locations
Identified by its waxy luster, translucency, and warm color palette. Often found in riverbeds or volcanic regions like Brazil, India, and Madagascar.
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