sedimentary
Polished River Jasper
Silicon Dioxide (SiO2) with iron and other mineral inclusions
Hardness: 6.5-7 (Mohs scale), Color: Variegated greens, reds, and browns, Luster: Vitreous to waxy (when polished), Crystal Structure: Trigonal/Microcrystalline, Specific Gravity: 2.58-2.91
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs scale), Color: Variegated greens, reds, and browns, Luster: Vitreous to waxy (when polished), Crystal Structure: Trigonal/Microcrystalline, Specific Gravity: 2.58-2.91
Formation & geological history
Forms when silica-rich fluids permeate through fractured rock or volcanic ash, slowly precipitating microcrystalline quartz. The coloration is derived from iron oxides and clay inclusions. This specific specimen has been worn smooth by fluvial (water) action.
Uses & applications
Primarily used for lapidary work, jewelry, decorative cabochons, and as holistic healing stones. In primitive times, used for tool making due to its conchoidal fracture.
Geological facts
Jasper is a variety of chalcedony. The name comes from the Greek word 'iaspis', meaning 'spotted stone'. It is known for its incredible opacity compared to agate.
Field identification & locations
Identify by its hardness (cannot be scratched by a steel knife) and its smooth, waxy feel. Commonly found in riverbeds and coastal areas globally. Collectors look for unique color patterns and orbital markings.
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