sedimentary
Yellow Jasper
Jasper (Silicon Dioxide, SiO2)
Hardness: 6.5-7 (Mohs scale), Color: Mustard yellow to brownish-yellow, Luster: Dull to waxy, Crystal structure: Trigonal/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: Mustard yellow to brownish-yellow, Luster: Dull to waxy, Crystal structure: Trigonal/Microcrystalline, Cleavage: None (Conchoidal fracture), Specific Gravity: 2.58-2.91
Formation & geological history
Formed through the infiltration of silica-rich fluids into volcanic ash or fine-grained sediments, often associated with hydrothermal activity. Its yellow color comes from high concentrations of goethite or iron oxides.
Uses & applications
Used primarily as a decorative gemstone, in cabochons, beads, and metaphysical carvings. Historically used for making tools due to its sharp conchoidal fracture.
Geological facts
Jasper is an opaque variety of chalcedony. Yellow jasper has been used since antiquity as a stone of protection and was often called the 'rain bringer' by Native American tribes.
Field identification & locations
Identify in the field by its opacity, smooth conchoidal fracture surfaces, and inability to be scratched by a steel knife. Commonly found in riverbeds and desert environments in regions like Oregon, Madagascar, and South Africa.
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