sedimentary
Yellow Jasper
Silicon Dioxide (SiO2)
Hardness: 6.5-7 (Mohs); Color: Mustard yellow, golden brown, tan; Luster: Vitreous to greasy; Crystal Structure: Microcrystalline/Trigonal; Cleavage: None; Specific Gravity: 2.58-2.91
- Hardness
- 6
- Color
- Mustard yellow, golden brown, tan
- Luster
- Vitreous to greasy
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Physical properties
Hardness: 6.5-7 (Mohs); Color: Mustard yellow, golden brown, tan; Luster: Vitreous to greasy; Crystal Structure: Microcrystalline/Trigonal; Cleavage: None; Specific Gravity: 2.58-2.91
Formation & geological history
Formed through the deposition of silica from water solutions or volcanic ash, followed by cementation over millions of years. Its yellow hue is caused by high iron (goethite) content.
Uses & applications
Used primarily for ornamental purposes, lapidary arts, jewelry (cabochons and beads), and as a collector's decorative sphere.
Geological facts
Jasper is an opaque variety of chalcedony. Yellow Jasper was historically used as a 'stone of protection' for travelers and is often found in large nodules or beds.
Field identification & locations
Identify by its opaque nature, smooth waxy surface when polished, and distinctive mustard-yellow mottling. Common in South Africa, Madagascar, and the USA.
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