fossil

Fossilized crinoid columnal (likely crinoid stem segment)

Crinoidea; commonly preserved as calcite, CaCO₃

AI-generated identification · may be incorrect

Hardness about 3 on Mohs scale; gray-brown to cream, typically dull to pearly, with ridged or segmented cylindrical morphology and calcite cleavage. The visible specimen appears to be a weathered, fossilized stem piece rather than a conventional rock.

Identified August 13, 2026More fossil →

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Physical properties

Formation & geological history

Crinoids were marine animals whose stems accumulated on Paleozoic seafloors and were rapidly buried and mineralized, commonly during the Ordovician–Permian (about 485–252 million years ago). The surrounding pale matrix is likely limestone.

Uses & applications

Primarily collected, displayed, and used educationally; polished crinoid limestone is occasionally used for ornamental stone and jewelry. Scientific value depends on locality and preservation.

Geological facts

Crinoid stem segments are called columnals and often show star-shaped or circular internal features; abundant fragments can form “crinoidal limestone.”

Field identification & locations

Look for repeated discs, radial ridges, and calcite reaction to dilute hydrochloric acid. Common in Paleozoic marine limestones of the central and eastern United States, the United Kingdom, and Europe.