sedimentary
Yellow Jasper
Silicon Dioxide (SiO2) with Goethite/Limonite inclusions
Hardness: 6.5-7 (Mohs scale), Color: Mustard yellow to golden brown, Luster: Vitreous to waxy, Crystal Structure: Trigonal (Microcrystalline), Cleavage: None, Fracture: Conchoisdal/Splintery
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs scale), Color: Mustard yellow to golden brown, Luster: Vitreous to waxy, Crystal Structure: Trigonal (Microcrystalline), Cleavage: None, Fracture: Conchoisdal/Splintery
Formation & geological history
Formed through the deposition of silica from water-rich environments, often in volcanic ash beds or near hydrothermal veins where iron oxides (like goethite) permeate the silica during solidification.
Uses & applications
Primarily used for lapidary work, jewelry (cabochons), interior decoration, and as a popular specimen for rock collectors and practitioners of crystal healing.
Geological facts
Jasper is an opaque variety of chalcedony. The yellow hue is almost always caused by tiny inclusions of iron hydroxide minerals. It has been used since antiquity for seals, amulets, and ornamentation across Egyptian and Minoan cultures.
Field identification & locations
Identify in the field by its hardness (will scratch glass), opaque nature, and smooth, waxy feel when wet or polished. Commonly found in riverbeds, desert regions, and areas with historic volcanic activity like the Oregon coast or Madagascar.
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