sedimentary

Tumbled iron-rich chert or jasper

Microcrystalline quartz (SiO₂), likely limonitic/hematitic variety

AI-generated identification · may be incorrect

Opaque ochre-brown, earthy to dull luster, irregular naturally worn shape, and no visible crystal faces or cleavage. Quartz hardness is about Mohs 7; the rusty color suggests iron-oxide staining, though the image cannot confirm composition.

Identified August 16, 2026More sedimentary →

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Physical properties

Formation & geological history

Likely silica-rich sediment or chemically precipitated chert later silicified and naturally rounded by weathering or water abrasion. Chert forms across many geological ages, commonly in marine sedimentary environments.

Uses & applications

Used as an ornamental stone, carving material, tumbled stone, and historically for sharp tools or fire-starting when sufficiently fresh. This small, low-grade piece has little commercial value.

Geological facts

Chert and jasper are varieties of microcrystalline quartz; jasper is typically opaque and strongly colored by iron oxides or other impurities. Its surface appears water-worn or tumbled rather than freshly fractured.

Field identification & locations

Look for a glassy/waxy surface, very fine grain, conchoidal fracture, and inability to scratch with a steel knife; it should scratch ordinary glass if quartz-rich. Common in gravel beds, river deposits, and sedimentary formations worldwide.