sedimentary
Yellow Jasper
Jasper (Silica-rich Microcrystalline Quartz, SiO2 with Iron impurities)
Hardness: 6.5–7 on Mohs scale; Color: Mustard yellow to golden brown; Luster: Vitreous to waxy; Structure: Microcrystalline (trigonal); Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.6–2.9.
- Hardness
- 6
- Color
- Mustard yellow to golden brown
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5–7 on Mohs scale; Color: Mustard yellow to golden brown; Luster: Vitreous to waxy; Structure: Microcrystalline (trigonal); Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.6–2.9.
Formation & geological history
Formed from silica-rich fluids depositing in the cavities of sedimentary or volcanic rocks. The yellow color comes from the inclusion of Goethite or other iron oxides during the silicification process.
Uses & applications
Primarily used for lapidary work, jewelry (cabochons and beads), metaphysical practices, and as a collector's specimen.
Geological facts
Jasper have been used as gemstones since antiquity and can be found in the jewelry of ancient Egypt and Mesopotamia. It is an opaque variety of chalcedony.
Field identification & locations
Look for a smooth, waxy texture and shell-like (conchoidal) fractures. It will scratch glass but cannot be scratched by a steel knife. Commonly found in riverbeds or coastal areas where erosion exposes silica nodules.
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