sedimentary
Yellow Jasper (Chert variant)
Silicon Dioxide (SiO2) with iron inclusions
Hardness: 6.5-7 on Mohs scale; Color: Mustard yellow to brownish-gold; Luster: Vitreous to waxy; Crystal Structure: Microcrystalline (Trigonal); Cleavage: None (Conchoidal fracture); Specific Gravity: 2.6-2.9.
- Hardness
- 6
- Color
- Mustard yellow to brownish-gold
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 on Mohs scale; Color: Mustard yellow to brownish-gold; Luster: Vitreous to waxy; Crystal Structure: Microcrystalline (Trigonal); Cleavage: None (Conchoidal fracture); Specific Gravity: 2.6-2.9.
Formation & geological history
Formed through the deposition of silica from water solutions into fissures or cavities in volcanic or sedimentary rocks. The yellow color is caused by the presence of iron oxide (goethite) during the crystallization process.
Uses & applications
Commonly used for lapidary work, cabochons, beads for jewelry, and ornamental home decor. It is also popular in holistic healing and among mineral collectors.
Geological facts
Jasper is an opaque variety of chalcedony. Historically, it has been used for centuries to fashion tools like scrapers and arrowheads because of its conchoidal fracturing which creates sharp edges.
Field identification & locations
Identify in the field by its opacity (compared to translucent agate), waxy luster when polished, and high hardness (it will scratch glass). Commonly found in riverbeds, desert regions, and areas with volcanic history.
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