sedimentary
Jasper (with Agate/Chalcedony inclusions)
Silicon Dioxide (SiO2)
Hardness: 6.5-7 (Mohs scale), Color: Red, white, and translucent grey swirls, Luster: Waxy to vitreous when wet or polished, Crystal Structure: Microcrystalline (trigonal), Cleavage: None (conchoidal fracture)
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs scale), Color: Red, white, and translucent grey swirls, Luster: Waxy to vitreous when wet or polished, Crystal Structure: Microcrystalline (trigonal), Cleavage: None (conchoidal fracture)
Formation & geological history
Formed through the deposition of silica from volcanic ash or hydrothermal solutions into cavities or fissures. This specimen likely tumbled in a river or stream, resulting in its smooth, rounded shape.
Uses & applications
Used primarily for lapidary work, jewelry (cabochons and beads), ornamental stones, and as a popular specimen for rock tumbling and collecting.
Geological facts
Jasper is an opaque variety of chalcedony; when it has translucent areas like the grey/white sections seen here, it is often transitioning into agate. These stones have been used since antiquity for seals and amulets.
Field identification & locations
Identify in the field by its hardness (cannot be scratched by a steel knife), smooth 'river-worn' texture, and colorful swirls. Commonly found in riverbeds and gravel pits in volcanic regions.
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