sedimentary

Chert (Jasper variation)

Microcrystalline Quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale); Color: Brownish-red to earthy orange with grey streaks; Luster: Dull to waxy; Structure: Cryptocrystalline; Cleavage: None (Conchoidal fracture).

Hardness: 6
Color: Brownish-red to earthy orange with grey streaks
Luster: Dull to waxy

Identified July 14, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Brownish-red to earthy orange with grey streaks; Luster: Dull to waxy; Structure: Cryptocrystalline; Cleavage: None (Conchoidal fracture).

Formation & geological history

Forms through the accumulation of silica-rich microfossils on the seafloor or through the replacement of limestone. This specimen appears water-worn, likely from a fluvial (river) environment.

Uses & applications

Historically used for stone tools due to sharp edges; currently used for lapidary work, jewelry, and as decorative gravel.

Geological facts

Chert is so durable that it often survives long-term erosion, often found as smooth pebbles in riverbeds far from its source rock. Red versions are often called Jasper.

Field identification & locations

Identify by its hardness (it will scratch glass) and its smooth, waxy feel when wet. Found globally in sedimentary basins. Look for smooth, rounded shapes in stream beds.