sedimentary
Jasper with Quartz Vein
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Hardness: 6.5-7 on Mohs scale; Color: Dark greyish-green with a white vein; Luster: Dull to vitreous; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.91
- Hardness
- 6
- Color
- Dark greyish-green with a white vein
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6.5-7 on Mohs scale; Color: Dark greyish-green with a white vein; Luster: Dull to vitreous; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.91
Formation & geological history
Formed from the deposition of silica in hydrothermal environments or through the replacement of organic material/volcanic ash. The white vein suggests a secondary 'crack-seal' event where mineral-rich water deposited crystalline quartz in a fracture long after the initial rock solidified.
Uses & applications
Used primarily for lapidary work, jewelry (cabochons), as decorative landscaping stones, and as a common collectible for rockhounds.
Geological facts
Jasper is a variety of chalcedony. The presence of veins or 'bands' often leads to specialized names like 'Basanite' if the host is black, though this specimen is likely a silicated shale or river-worn jasper pebble.
Field identification & locations
Identify in the field by its smooth, waxy texture and inability to be scratched by a steel knife. Commonly found in riverbeds, glacial tills, and coastal beaches. Collectors should look for unique inclusion patterns.
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