sedimentary
Jasper / Chert (tumbled/water-worn)
Microcrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness 6.5-7, opaque, brown and dark grey/black colors, waxy to dull luster, conchoidal fracture
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Physical properties
Hardness 6.5-7, opaque, brown and dark grey/black colors, waxy to dull luster, conchoidal fracture
Formation & geological history
Formed from silica-rich fluids in sedimentary environments or as nodules in limestone/chalk. Often rounded by water action in rivers or beaches.
Uses & applications
Common lapidary material, decorative stones, historical tool making
Geological facts
Jasper is an impure variety of silica, usually red, yellow, brown or green in color; and rarely blue.
Field identification & locations
Identify by hardness (scratches glass), smooth conchoidal fracture, and opacity. Commonly found in riverbeds and beaches.
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