sedimentary
Yellow Jasper
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
Hardness: 6.5-7.0 (Mohs scale); Color: Mustard yellow, tan, golden-brown; Luster: Vitreous to waxy; Structure: Microcrystalline; Specific Gravity: 2.6-2.7
- Hardness
- 6
- Color
- Mustard yellow, tan, golden-brown
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7.0 (Mohs scale); Color: Mustard yellow, tan, golden-brown; Luster: Vitreous to waxy; Structure: Microcrystalline; Specific Gravity: 2.6-2.7
Formation & geological history
Formed via the accumulation of silica-rich fluids in volcanic ash or sedimentary deposits, often during the Paleozoic or Mesozoic eras. The yellow color is derived from iron hydroxide inclusions (Goethite).
Uses & applications
Primarily used for lapidary work, decorative cabochons, metaphysical crystals, and jewelry making.
Geological facts
Jasper is an opaque variety of chalcedony. Yellow jasper was historically used by ancient civilizations as a protective amulet for travelers and shamans.
Field identification & locations
Identified by its opacity (even on thin edges), smooth conchoidal fracture, and inability to be scratched by a steel knife. Found globally, with notable deposits in South Africa, USA, and Madagascar.
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