sedimentary
Chert / Red Jasper
Microcrystalline Quartz (SiO2)
Hardness: 6.5-7 (Mohs scale), Color: Reddish-pink to white/grey, Luster: Waxy to dull, Crystal Structure: Trigonal (microcrystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.7
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs scale), Color: Reddish-pink to white/grey, Luster: Waxy to dull, Crystal Structure: Trigonal (microcrystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.7
Formation & geological history
Formed from the accumulation of silica-rich microfossils or precipitation from hydrothermal fluids in sedimentary basins. The red color suggests iron oxide impurities.
Uses & applications
Historically used for stone tools and arrowheads; currently used for lapidary work, jewelry, and collector specimens.
Geological facts
This specimen shows distinct conchoidal fracturing and iron-rich banding. Red varieties are often called jasper, which has been used in jewelry for thousands of years.
Field identification & locations
Look for smooth, waxy surfaces and curved, glass-like fractures. It will easily scratch glass but cannot be scratched by a steel knife. Common in ancient sedimentary beddings.
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