sedimentary
Red Jasper
Silicon Dioxide (SiO2) with Hematite impurities
Hardness: 6.5-7 (Mohs); Color: deep brick red; Luster: dull to vitreous; Structure: Microcrystalline/Cryptocrystalline; Cleavage: none; SG: 2.58-2.91
- Hardness
- 6
- Color
- deep brick red
- Luster
- dull to vitreous
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Physical properties
Hardness: 6.5-7 (Mohs); Color: deep brick red; Luster: dull to vitreous; Structure: Microcrystalline/Cryptocrystalline; Cleavage: none; SG: 2.58-2.91
Formation & geological history
Formed from silica-rich precipitates in sedimentary environments or volcanic ash during hydrothermal processes. The red color comes from iron oxide (hematite) inclusions.
Uses & applications
Used for ornamental carvings, jewelry (cabochons, beads), decorative stones in landscaping, and as a polishing media in rock tumblers.
Geological facts
Jasper is an opaque variety of chalcedony. Historically, it was known as the 'supreme nurturer' and has been used since antiquity in seals and ornaments.
Field identification & locations
Identify by its opacity (even on thin edges), its characteristic 'brick' red color, and its smooth, conchoidal fracture when broken. Frequently found in riverbeds and gravel pits in the American Midwest and Western states.
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