mineral
Blue Chalcedony
Cryptocrystalline Silicon Dioxide (SiO2)
Hardness: 6.5 - 7 (Mohs scale), Color: Pale blue to lavender-blue, Luster: Waxy to vitreous, Crystal Structure: Trigonal (microcrystalline), Cleavage: None, Specific Gravity: 2.58 - 2.64
- Hardness
- 6
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Physical properties
Hardness: 6.5 - 7 (Mohs scale), Color: Pale blue to lavender-blue, Luster: Waxy to vitreous, Crystal Structure: Trigonal (microcrystalline), Cleavage: None, Specific Gravity: 2.58 - 2.64
Formation & geological history
Formed through the deposition of silica-rich water in volcanic and sedimentary environments, often filling cavities (vugs) or fissures in rocks. It commonly occurs in geodes or as botryoidal masses.
Uses & applications
Extensively used as a gemstone for jewelry (cabochons, beads), decorative carvings, and as a popular specimen for mineral collectors due to its calming color.
Geological facts
The name 'Chalcedony' is derived from the ancient Greek town of Chalcedon in Asia Minor. Known for its ability to exhibit the Tyndall effect, which causes the blue color through light scattering.
Field identification & locations
Identified by its waxy luster, lack of cleavage, and ability to scratch glass. Commonly found in Namibia, Turkey, India, and the United States. Value increases with color intensity and translucency.
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