sedimentary
Jasper / Chert (River Stone)
Cryptocrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness: 6.5-7. Color: Yellow, orange, brown. Luster: Waxy to dull. Crystal structure: Cryptocrystalline. Cleavage: None, conchoidal fracture.
- Hardness
- 6
- Color
- Yellow, orange, brown
- Luster
- Waxy to dull
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Physical properties
Hardness: 6.5-7. Color: Yellow, orange, brown. Luster: Waxy to dull. Crystal structure: Cryptocrystalline. Cleavage: None, conchoidal fracture.
Formation & geological history
Formed from silica-rich fluids in sedimentary environments, often replacing other minerals or forming nodules. Smoothness is due to river or wave action.
Uses & applications
Commonly tumbled for lapidary use, collected for aesthetic purposes.
Geological facts
Stones like this are often found in riverbeds or beaches where water has naturally tumbled and smoothed them.
Field identification & locations
Identify by its hardness (scratches glass), waxy luster, and lack of visible crystals. Commonly found in river gravels and beaches worldwide.
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