mineral
Chalcedony (Quartz Pebble)
Cryptocrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness: 6.5-7 Mohs; Color: Translucent grayish-tan with cloudy white inclusions; Luster: Waxy to vitreous; Crystal Structure: Hexagonal (trigonal); Cleavage: None/Conchoidal fracture.
- Hardness
- 6
- Color
- Translucent grayish-tan with cloudy white inclusions
- Luster
- Waxy to vitreous
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Physical properties
Hardness: 6.5-7 Mohs; Color: Translucent grayish-tan with cloudy white inclusions; Luster: Waxy to vitreous; Crystal Structure: Hexagonal (trigonal); Cleavage: None/Conchoidal fracture.
Formation & geological history
Formed from the deposition of silica from aqueous solutions, often in volcanic or sedimentary environments. This specimen is water-worn, suggesting transport via river or coastal activity.
Uses & applications
Used for semi-precious jewelry, lapidary art (tumbling), and historically for tool making (flint knapping).
Geological facts
Chalcedony is formed by microscopic crystals of quartz and moganite. Its name is derived from the ancient Greek town of Chalcedon in Asia Minor.
Field identification & locations
Identify by its characteristic waxy luster and translucency when held to light. Found globally in gravel beds, shorelines, and basaltic regions.
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