sedimentary
Jasper Pebble
Silicon dioxide (SiO2) with impurities
Hardness: 6.5-7 (Mohs), Color: Reddish-brown, Luster: Dull to sub-vitreous, Structure: Microcrystalline, Cleavage: None (conchoidal fracture), Specific Gravity: 2.58-2.91
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs), Color: Reddish-brown, Luster: Dull to sub-vitreous, Structure: Microcrystalline, Cleavage: None (conchoidal fracture), Specific Gravity: 2.58-2.91
Formation & geological history
Formed from silica-rich fluids that permeated through sedimentary rocks or volcanic ash, eventually recrystallizing into a dense chalcedony. This specific rounded shape is the result of water erosion in riverbeds or beaches.
Uses & applications
Used primarily for lapidary work, jewelry (beads, cabochons), and as decorative landscaping stone.
Geological facts
Jasper is often found in riverbanks and is a favorite for hobbyists with rock tumblers because it polishes to a very high shine. The red color is usually caused by iron oxide (hematite) inclusions.
Field identification & locations
Identify by its hardness (it will scratch glass), opaque nature, and smooth, water-worn exterior if found near water. Common in river deposits and gravel pits worldwide.
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