sedimentary
Yellow Jasper
Silicon Dioxide (SiO2) with hydrated iron oxide impurities (Goethite or Limonite)
Hardness: 6.5-7 (Mohs scale), Color: Mustard yellow to brownish-yellow with darker mottling, Luster: Waxy to vitreous when wet or polished, Structure: Microcrystalline/Cryptocrystalline, Fracture: Conchoidal
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs scale), Color: Mustard yellow to brownish-yellow with darker mottling, Luster: Waxy to vitreous when wet or polished, Structure: Microcrystalline/Cryptocrystalline, Fracture: Conchoidal
Formation & geological history
Formed through the deposition of silica-rich fluids within volcanic ash or sedimentary beds. The yellow coloration is caused by the inclusion of iron oxides during the silicification process.
Uses & applications
Commonly used in lapidary work for cabochons, beads, and tumbled stones. Also used as a decorative stone in landscaping and aquariums.
Geological facts
Jasper is an opaque variety of chalcedony. Historically, it was known as a stone of endurance and protection. The name 'Jasper' is derived from the Greek word 'iaspis', meaning spotted stone.
Field identification & locations
Identify in the field by its opacity (even on thin edges) and smooth, shell-like fracture pattern. Often found in riverbeds or coastal gravels where water action has smoothed the exterior.
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