sedimentary
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Hardness: 6.5-7.0 (Mohs scale); Color: Brick red to brownish-red; Luster: Dull to vitreous; Crystal Structure: Hexagonal (Microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.91
- Hardness
- 6
- Color
- Brick red to brownish-red
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6.5-7.0 (Mohs scale); Color: Brick red to brownish-red; Luster: Dull to vitreous; Crystal Structure: Hexagonal (Microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.91
Formation & geological history
Formed primarily as a secondary mineral in volcanic or sedimentary environments where silica-rich fluids permeate through rock cavities, often during the Proterozoic to Phanerozoic eons. Its red color comes from high concentrations of iron oxide (hematite).
Uses & applications
Used extensively in lapidary arts for jewelry, beads, cabochons, and small carvings. Historically used for making tools like scrapers due to its conchoidal fracture.
Geological facts
Jasper was a favorite gem in antiquity and is mentioned in many historical texts, including the Bible. The name comes from the Greek word 'iaspis', meaning spotted stone.
Field identification & locations
Identify by its smooth, waxy feel and characteristic shell-like (conchoidal) fracture pattern when broken. It cannot be scratched by a steel knife. Common in fossil-bearing beds and desert regions.
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