sedimentary

Polished fossiliferous chert or silicified limestone pebble

Microcrystalline quartz (SiO₂), possibly with calcite and iron-oxide inclusions

AI-generated identification · may be incorrect

Hardness about 6.5–7 if chert; brown to cream coloration, waxy to dull luster, and no visible crystal cleavage. Rounded, polished surfaces and small cavities/inclusions suggest a naturally weathered or tumbled sedimentary specimen.

Identified September 14, 2026More sedimentary →

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Physical properties

Formation & geological history

Likely formed from silica-rich sediment or replacement of carbonate material, with iron oxides producing the brown color; exact geological age cannot be determined from the image. Rounded shape indicates transport by water or human tumbling.

Uses & applications

Used as a decorative pebble, lapidary material, paperweight, or teaching specimen; too small and irregular for construction use. Collector value is mainly aesthetic.

Geological facts

The pale patches and pits may represent altered fossils, vugs, or weathered mineral inclusions rather than true fossil shells. A steel file should not easily scratch genuine chert, while quartz-rich areas can scratch glass.

Field identification & locations

Common in river gravels and sedimentary terrains worldwide, including flint and chert-bearing regions. Confirm with a hardness test, streak (typically white), and acid test on a hidden spot for carbonate content.