sedimentary
Jasper
Silicon Dioxide (Microcrystalline Quartz), SiO2
Hardness of 6.5 to 7 on the Mohs scale, typically brown, red, yellow, or green due to iron oxide impurities, waxy to dull luster, cryptocrystalline structure with no visible cleavage, and a specific gravity of 2.65 to 2.66.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, typically brown, red, yellow, or green due to iron oxide impurities, waxy to dull luster, cryptocrystalline structure with no visible cleavage, and a specific gravity of 2.65 to 2.66.
Formation & geological history
Formed through the precipitation of silica-rich fluids or silty radiolarian oozes in marine environments, often associated with hydrothermal activity or volcanic-sedimentary processes, dating from various geological eras.
Uses & applications
Used in ornamental carvings, cabochons, jewelry, decorative objects, and as a polishing aggregate.
Geological facts
Jasper has been used for thousands of years by ancient civilizations to create tools, seals, and jewelry. The name means 'spotted or speckled stone'.
Field identification & locations
Found worldwide in riverbeds, glacial tills, and ancient marine deposits; easily identified in the field by its hardness, conchoidal fracture, and opaque earthy colors.
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