mineral
Chalcedony
Cryptocrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness: 6.5-7 on Mohs scale; Color: waxy translucent greyish-white to tan; Luster: waxy to vitreous; Crystal structure: Trigonal/Monoclinic; Specific gravity: 2.6-2.64
- Hardness
- 6
- Color
- waxy translucent greyish-white to tan
- Luster
- waxy to vitreous
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Physical properties
Hardness: 6.5-7 on Mohs scale; Color: waxy translucent greyish-white to tan; Luster: waxy to vitreous; Crystal structure: Trigonal/Monoclinic; Specific gravity: 2.6-2.64
Formation & geological history
Secondary formation through the deposition of silica from aqueous solutions in volcanic and sedimentary environments, often filling nodules, cavities, or fractures.
Uses & applications
Commonly used in jewelry as cabochons, for ornamental carvings, and historically for stone tools and seals due to its toughness and fracture properties.
Geological facts
Chalcedony has been a prized gemstone since antiquity, notably used in ancient Mediterranean civilizations for cylinder seals and amulets.
Field identification & locations
Identify by its waxy luster, translucency, and conchoidal fracture. Often found along riverbeds or in volcanic outcrop areas like Oregon, Brazil, and India.
