sedimentary
Orbicular Jasper (Eye Jasper / Kambaba-like pattern)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Hardness: 6.5-7 (Mohs scale); Color: Black, grey, and white; Luster: Dull to waxy; Structure: Microcrystalline (trigonal); Cleavage: None/Conchoidal fracture; Specific gravity: approx. 2.6
- Hardness
- 6
- Color
- Black, grey, and white
- Luster
- Dull to waxy
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Black, grey, and white; Luster: Dull to waxy; Structure: Microcrystalline (trigonal); Cleavage: None/Conchoidal fracture; Specific gravity: approx. 2.6
Formation & geological history
Formed from the precipitation of silica in volcanic or sedimentary environments, where minerals (like amphiboles or quartz) crystallize around a nucleus to form circular 'orbs'. Often associated with Precambrian or Paleozoic eras.
Uses & applications
Used primarily in lapidary arts for cabochons, beads, and ornamental carvings. Also popular as a palm stone for metaphysical collectors.
Geological facts
While often called Jasper, many specimens with this specific circular 'eye' pattern in black and grey are actually a silicified rhyolite or a form of fossilized algae (stromatolite) if the structure is biological in origin.
Field identification & locations
Identify in the field by its distinct circular patterns (eyes) and extreme hardness; it will scratch glass but cannot be scratched by a steel knife. Common in Madagascar and parts of the USA.
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