sedimentary
Orbicular Jasper (Ocean Jasper or Poppy Jasper variant)
Silicon Dioxide (SiO2) with various inclusions
Hardness: 6.5-7 (Mohs scale), Color: Brown, tan, and grey with 'orb' patterns, Luster: Dull/Waxy (unfinished), Crystal Structure: Trigonal/Microcrystalline (Cryptocrystalline quartz), Cleavage: None
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs scale), Color: Brown, tan, and grey with 'orb' patterns, Luster: Dull/Waxy (unfinished), Crystal Structure: Trigonal/Microcrystalline (Cryptocrystalline quartz), Cleavage: None
Formation & geological history
Formed from silica-rich fluids precipitating in crevices or gas pockets of volcanic rocks or sedimentary environments. These 'orbs' occur as spherulitic structures during the crystallization of the silica.
Uses & applications
Primarily used for lapidary work, including tumbling for decorative stones, cabochons for jewelry, and as a collectible specimen for rockhounds.
Geological facts
Jasper is an opaque variety of chalcedony. The 'orbicular' pattern is relatively rare and caused by the radial growth of fibrous minerals (like feldspar or quartz) within the jasper matrix.
Field identification & locations
Identify in the field by its distinct circular patterns (eyes/orbs) and its hardness—it will scratch glass and cannot be scratched by a steel knife. Frequently found in beach gravels or riverbanks in areas with volcanic activity.
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