sedimentary
Yellow Jasper
Silicon Dioxide (SiO2) with Goethite/Iron oxide inclusions
Hardness: 6.5 to 7 on Mohs scale; Color: Mustard yellow, ochre, or tan; Luster: Dull to vitreous; Crystal Structure: Microcrystalline/Cryptocrystalline (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58 to 2.91
- Hardness
- 6
- Color
- Mustard yellow, ochre, or tan
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6.5 to 7 on Mohs scale; Color: Mustard yellow, ochre, or tan; Luster: Dull to vitreous; Crystal Structure: Microcrystalline/Cryptocrystalline (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58 to 2.91
Formation & geological history
Formed from the deposition of silica-rich fluids in volcanic ash or sedimentary rocks. The yellow hue is derived from hydrated iron oxide (goethite) trapped during the crystallization process. It can be found in layers or nodules in various geological settings.
Uses & applications
Used primarily as a lapidary material for cabochons, beads, and carvings. Also popular in the metaphysical community and used historically as an ornamental building stone or for tool making (due to its sharp fracture edges).
Geological facts
Jasper has been used by humans for thousands of years; it was a favorite gem in the ancient world, mentioned in biblical texts and used in the seals of ancient Babylon. The yellow variety is often associated with the 'solar plexus' in spiritual practices.
Field identification & locations
Identify in the field by its opaque nature (unlike translucent chalcedony), its high hardness (it will scratch glass), and its distinctive smooth, waxy fracture surface. It is commonly found in riverbeds or desert regions where volcanic activity once occurred.
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