sedimentary
Jasper
Silicon dioxide (SiO2)
Hardness: 6.5-7.0 (Mohs scale), Color: Red/Brownish-red due to iron inclusions, Luster: Vitreous to waxy, Crystal structure: Hexagonal (microcrystalline quartz), Cleavage: None, Fracture: Conchoidal.
- Hardness
- 6
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Physical properties
Hardness: 6.5-7.0 (Mohs scale), Color: Red/Brownish-red due to iron inclusions, Luster: Vitreous to waxy, Crystal structure: Hexagonal (microcrystalline quartz), Cleavage: None, Fracture: Conchoidal.
Formation & geological history
Formed from the deposition of silica-rich fluids within volcanic or sedimentary environments. The red pigmentation is typical of iron oxide (hematite) staining of the cryptocrystalline quartz structure.
Uses & applications
Commonly used for lapidary work, jewelry (cabochons), ornamental decoration, and as a semi-precious collector's stone.
Geological facts
Jasper has been used as a gemstone since antiquity. In many cultures, red jasper was believed to have protective properties and was often used in amulets and cylinder seals.
Field identification & locations
Identify by its opacity (unlike translucent carnelian), conchoidal fracture, and inability to be scratched by a steel knife. Commonly found in riverbeds or beaches where silica-rich rocks have undergone tumble-polishing naturally.
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