sedimentary
Yellow Jasper
Tectosilicates (SiO2) with Goethite/Iron oxide inclusions
Hardness: 6.5-7 (Mohs scale); Color: Mustard yellow to golden brown; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91
- Hardness
- 6
- Color
- Mustard yellow to golden brown
- Luster
- Vitreous to waxy
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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 (conchoidal fracture); Specific gravity: 2.58-2.91
Formation & geological history
Formed via the accumulation of microcrystalline quartz as sediment or as a replacement mineral in volcanic ash. The yellow color is derived from iron impurities (specifically goethite) during the silicification process.
Uses & applications
Commonly used in lapidary work for cabochons, beads, decorative carvings, and as a popular gemstone for collectors and metaphysical enthusiasts.
Geological facts
Jasper is an opaque variety of chalcedony. Yellow jasper is historically associated with spiritual protection and was used by ancient civilizations for amulets and seals.
Field identification & locations
Identify by its smooth, opaque, mustard-yellow appearance and extreme hardness (cannot be scratched by a steel knife). Commonly found in riverbeds or coastal deposits. Found globally, with notable deposits in South Africa, India, and the USA.
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