sedimentary
Jasper / Chert (Lake Superior Agate or similar chalcedony nodule)
Microcrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness 6.5-7 on Mohs scale. Opaque, orange/brown/yellow coloration with banding or inclusions. Waxy luster when polished. Conchoidal fracture.
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Physical properties
Hardness 6.5-7 on Mohs scale. Opaque, orange/brown/yellow coloration with banding or inclusions. Waxy luster when polished. Conchoidal fracture.
Formation & geological history
Formed from silica-rich fluids precipitating in voids in volcanic rocks or as sedimentary deposits. The orange/brown color comes from iron oxide impurities.
Uses & applications
Often used for lapidary arts, tumbled stones, jewelry, and collecting.
Geological facts
Jasper is a variety of chalcedony. The banding and iron staining are typical of stones found in glacial till or riverbeds, often sought after by rockhounds.
Field identification & locations
Identified by its hardness (scratches glass), lack of cleavage, and waxy luster. Common in riverbeds, beaches, and glacial deposits.
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