sedimentary
Jasper / Chert (river tumbled)
Microcrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness of 6.5-7 on Mohs scale. Opaque brown/tan color with some lighter and darker mottling. Waxy luster when wet or polished. Conchoidal fracture. Cryptocrystalline structure.
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Physical properties
Hardness of 6.5-7 on Mohs scale. Opaque brown/tan color with some lighter and darker mottling. Waxy luster when wet or polished. Conchoidal fracture. Cryptocrystalline structure.
Formation & geological history
Formed from silica-rich fluids precipitating in sedimentary environments. This specimen has been rounded by natural water action in a river or beach environment.
Uses & applications
Commonly used for lapidary work, tumbling, and decorative stones. Historically used for making stone tools.
Geological facts
Jasper is a variety of chalcedony that gets its opaque color from mineral impurities, often iron oxides.
Field identification & locations
Identified by its hardness (scratches glass), opaque nature, conchoidal fracture, and waxy feel. Very common in riverbeds and gravel deposits worldwide.
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