sedimentary
Brown Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Hardness: 6.5-7 on Mohs scale; Color: Reddish-brown to tan; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific Gravity: 2.58-2.91
- Hardness
- 6
- Color
- Reddish-brown to tan
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 on Mohs scale; Color: Reddish-brown to tan; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific Gravity: 2.58-2.91
Formation & geological history
Formed through the deposition of silica-rich fluids in cavities or volcanic ash, often associated with sedimentary processes or hydrothermal activity in volcanic rocks.
Uses & applications
Commonly used in lapidary work for cabochons, beads, and decorative ornaments. It is also a popular specimen for rock tumbling and collector sets.
Geological facts
Jasper is an opaque variety of chalcedony. Brown jasper specifically owes its color to high concentrations of goethite or limonite (iron oxides).
Field identification & locations
Identify by its waxy luster, smoothness when tumbled, and complete opacity (light does not pass through it). Often found in riverbeds and coastal areas globally.
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