sedimentary
Red Jasper (Polished)
Jasper (Iron-rich Microcrystalline Quartz, SiO2)
Hardness: 6.5-7 (Mohs scale), Color: Brick red to brownish-red with yellow and grey inclusions, Luster: Dull to Vitreous/Polished, Structure: Microcrystalline, Cleavage: None (conchoidal fracture), Specific Gravity: 2.58–2.91
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs scale), Color: Brick red to brownish-red with yellow and grey inclusions, Luster: Dull to Vitreous/Polished, Structure: Microcrystalline, Cleavage: None (conchoidal fracture), Specific Gravity: 2.58–2.91
Formation & geological history
Formed when silica-rich fluids permeate sedimentary rocks or volcanic ash, incorporating iron oxides that provide the red color. Typically found in ancient hydrothermal or sedimentary environments.
Uses & applications
Commonly used for lapidary work, decorative carvings, jewelry (cabochons), and as a collector's specimen. Historically used for making tools and seals.
Geological facts
Jasper is an opaque variety of chalcedony. The name 'Jasper' is derived from the Greek work 'iaspis', meaning 'spotted stone'. It was one of the stones used in the Breastplate of the High Priest in Biblical times.
Field identification & locations
Identify by its opacity (unlike translucent agate), red streak color, and hardness (cannot be scratched by a steel knife). Commonly found in riverbeds or mountain ranges in the Western US, India, and Brazil.
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