sedimentary

Weathered iron-rich chert or jasper pebble

Microcrystalline quartz (SiO₂), likely ferruginous chert/jasper

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque rusty orange, tan, and cream coloration; dull to waxy luster and very fine-grained texture. It lacks visible cleavage and typically has conchoidal fracture; the rounded shape indicates beach abrasion.

Identified September 10, 2026More sedimentary →

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Physical properties

Formation & geological history

Chert forms when silica-rich fluids replace or cement marine sediments, commonly during the Paleozoic–Mesozoic, while iron oxides produce the red-orange staining. Exact age and source cannot be determined from the photograph.

Uses & applications

Common pieces are used as decorative stones, lapidary material, tumbled stones, and occasionally tools; attractive patterned jasper can be cabochon-grade.

Geological facts

The specimen appears water-worn rather than freshly broken, and its granular beach setting contains many similar lithic fragments. A steel file should not easily scratch it, while it may scratch glass.

Field identification & locations

Look for a smooth waxy surface, opaque silica-rich body, rusty hematite/goethite staining, and conchoidal fracture; common along gravel beaches and river beds worldwide. Acid reaction would be absent or very weak.