mineral
Chalcedony (Agate Pebble)
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness: 6.5–7 on the Mohs scale; Color: Translucent yellow to honey-tan; Luster: Waxy to vitreous; Crystal structure: Trigonal/Monoclinic (Cryptocrystalline); Cleavage: None (Conchoidal fracture); Specific gravity: 2.6–2.64
- Hardness
- 6
- Color
- Translucent yellow to honey-tan
- Luster
- Waxy to vitreous
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Physical properties
Hardness: 6.5–7 on the Mohs scale; Color: Translucent yellow to honey-tan; Luster: Waxy to vitreous; Crystal structure: Trigonal/Monoclinic (Cryptocrystalline); Cleavage: None (Conchoidal fracture); Specific gravity: 2.6–2.64
Formation & geological history
Formed from the deposition of silica-rich water in cavities or veins within volcanic or sedimentary rocks. This specimen is water-worn, likely from a river or beach environment.
Uses & applications
Used for lapidary work (cabochons), jewelry (tumbled stones), and as a mineral collector's specimen.
Geological facts
Chalcedony is a cryptocrystalline form of silica, meaning its crystals are too small to be seen with a microscope. It is often the base material for agates, carnelians, and jaspers.
Field identification & locations
Identify in the field by its translucency (light passes through it), waxy surface texture, and inability to be scratched by a steel knife. Commonly found in riverbeds and gravel pits.
