sedimentary
Yellow Jasper
Silicon Dioxide (SiO2) with iron hydroxides (Goethite)
Hardness: 6.5-7 (Mohs scale), Color: Mustard yellow to golden brown, Luster: Waxy to vitreous, Structure: Microcrystalline/Cryptocrystalline (Hexagonal), Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.7
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs scale), Color: Mustard yellow to golden brown, Luster: Waxy to vitreous, Structure: Microcrystalline/Cryptocrystalline (Hexagonal), Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.7
Formation & geological history
Formed from the deposition of silica-rich fluids in cracks or volcanic ash beds. This specific specimen is an alluvial pebble, shaped and smoothed by river erosion over thousands of years.
Uses & applications
Used primarily in lapidary work for cabochons, beads, and ornamental carvings. Historically used for seals and amulets. Also popular in metaphysical 'gemstone' collections.
Geological facts
Yellow jasper has been a valued gemstone since antiquity, mentioned in ancient literature and used by early civilizations for its durability and bright color. Its yellow hue is caused by inclusions of goethite or limonite.
Field identification & locations
Identify in the field by its opacity (it does not transmit light like agate), its waxy texture when wet, and inability to be scratched by a steel knife. Common in riverbeds and coastal regions globally.
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