sedimentary
Yellow Jasper
Silicon Dioxide with Goethite (SiO2 + FeO(OH))
Hardness: 6.5-7 on Mohs scale; Color: Mustard yellow, golden brown, or ochre; Luster: Vitreous to greasy; Crystal Structure: Trigonal (Microcrystalline); Cleavage: None; Specific Gravity: 2.6-2.9
- Hardness
- 6
- Color
- Mustard yellow, golden brown, or ochre
- Luster
- Vitreous to greasy
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Physical properties
Hardness: 6.5-7 on Mohs scale; Color: Mustard yellow, golden brown, or ochre; Luster: Vitreous to greasy; Crystal Structure: Trigonal (Microcrystalline); Cleavage: None; Specific Gravity: 2.6-2.9
Formation & geological history
Formed through the deposition of silica from groundwater into volcanic or sedimentary cavities. Yellow varieties get their color from iron inclusions (goethite). These specimens often originate from alluvial deposits where river water has tumbled the stones over thousands of years.
Uses & applications
Used primarily in lapidary work, jewelry (beads, cabochons), home decor, and as a popular 'pocket stone' for collectors.
Geological facts
Jasper is an opaque variety of chalcedony. Historically, yellow jasper was used as a 'rain stone' and a protective talisman for travelers. It has been used in mosaics and jewelry since the Minoan civilization on Crete.
Field identification & locations
Identified in the field by its smooth, waxy texture when wet and its characteristic conchoidal fracture. Often found in riverbeds or coastal areas. Collectors should look for vibrancy of color and interesting patterns or 'mossy' inclusions within the stone.
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