sedimentary
Jasper
Microcrystalline Quartz (SiO2)
Hardness of 6.5-7 on the Mohs scale, waxy to dull luster, opaque appearance, conchoidal fracture, specific gravity of 2.55-2.91, colors often include yellow, brown, red, or green due to various mineral impurities.
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Physical properties
Hardness of 6.5-7 on the Mohs scale, waxy to dull luster, opaque appearance, conchoidal fracture, specific gravity of 2.55-2.91, colors often include yellow, brown, red, or green due to various mineral impurities.
Formation & geological history
Formed through the silification of sedimentary or volcanic rocks where silica-rich fluids replace organic material or fill cavities, occurring across various geological time periods.
Uses & applications
Used primarily for ornamental objects, cabochons, carvings, and as a collector's specimen.
Geological facts
Jasper has been used since ancient times for seals, signet rings, and various decorative arts. The yellow variety often gets its color from clay or iron hydroxide inclusions.
Field identification & locations
Identified in the field by its conchoidal fracture, lack of cleavage, microcrystalline structure, and opacity. Commonly found in riverbeds, alluvial gravels, and hydrothermal veins worldwide.
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