fossil

Polished fossiliferous limestone, likely crinoidal or coral limestone

Calcite (CaCO₃), fossiliferous carbonate rock

AI-generated identification · may be incorrect

Gray-brown, smoothly polished, with pale branching or network-like fossil structures and dull to pearly luster. Calcite has Mohs hardness 3, rhombohedral cleavage, and specific gravity about 2.7; it effervesces strongly in dilute hydrochloric acid.

Identified August 8, 2026More fossil →

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Physical properties

Formation & geological history

Formed from marine carbonate sediments and accumulated skeletal fragments, later compacted and lithified into limestone; the fossils are generally Paleozoic to Mesozoic in age, depending on locality.

Uses & applications

Primarily a decorative, lapidary, and educational specimen; polished pieces are used as paperweights, cabochons, and display stones, while limestone broadly is important for cement and aggregate.

Geological facts

The visible pale veins and branching patterns may be fossil fragments, stylolites, or calcite-filled fractures; a close inspection or acid test is needed for confident fossil identification.

Field identification & locations

Common in marine sedimentary formations worldwide, especially North America, Europe, and Asia. Look for fossil outlines, acid reaction, relatively low hardness, and absence of glassy quartz-like luster; avoid scratching the polished surface.