sedimentary
Yellow Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Hardness: 6.5-7 (Mohs scale), Color: Mustard yellow to golden brown, Luster: Dull to vitreous, Crystal Structure: Trigonal (microcrystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.58-2.91
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs scale), Color: Mustard yellow to golden brown, Luster: Dull to vitreous, Crystal Structure: Trigonal (microcrystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.58-2.91
Formation & geological history
Formed through the accumulation of fine-grained silica in hydrothermal veins or sedimentary environments, often associated with volcanic activity. Its yellow color comes from the inclusion of goethite or other iron oxides during formation.
Uses & applications
Used primarily for lapidary work, jewelry (cabochons and beads), decorative ornaments, and as a collector's mineral. Historically used for making tools due to its sharp conchoidal fracture.
Geological facts
Jasper is an opaque variety of chalcedony. In ancient times, it was considered a 'nurturing stone' and was often used in amulets. 'Yellow Jasper' specifically has been used by various cultures to represent the sun and protection during travel.
Field identification & locations
Identify in the field by its waxy-to-dull luster, extreme hardness (it will scratch glass), and its characteristic smooth, curved (conchoidal) breaks. Often found in riverbeds or areas with volcanic history.
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