fossil

Fossiliferous limestone pebble

Bioclastic limestone, likely containing worn marine fossils (possibly gastropods or bivalves)

AI-generated identification · may be incorrect

Cream to tan, fine-grained, dull to subtly waxy surface with brown fossil markings and fractures; chiefly calcite (Mohs hardness 3, nonmetallic luster, trigonal crystal structure, poor cleavage). It should effervesce strongly with dilute hydrochloric acid or vinegar, though weathering may reduce the reaction.

Identified September 4, 2026More fossil →

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Physical properties

Formation & geological history

Forms from compacted and cemented marine shell or skeletal debris, later rounded and polished naturally or by tumbling; the fossils may date from Paleozoic to Cenozoic marine sedimentary deposits, depending on locality.

Uses & applications

Used as a decorative stone, fossil specimen, and teaching or collecting material; limestone also serves in cement, aggregate, lime, and building stone.

Geological facts

The swirling markings are likely cross-sections or partial impressions of fossil shells rather than mineral crystals. Rounded shape suggests stream transport, beach abrasion, or human tumbling.

Field identification & locations

Look for identifiable shell chambers, growth lines, or pore-like textures and test a fresh spot for acid reaction; common sources include marine limestone beds worldwide. Exact identification requires a close-up of the fossil structures and locality information.