Crinoid

Fossil sea lilies — animals related to starfish — usually found as stacked, button-shaped stem pieces.

Crinoid specimen — Photo: James St. John, CC BY 2.0, via Wikimedia Commons

How to identify crinoid

Small round discs, often with a hole in the center.
Stacked into stem segments like beads.
Fizzes in acid (calcite).

Often confused with

Petoskey Stone
Petoskey stones show a honeycomb of six-sided coral cells.
Compare side by side

Where it's found

Burlington Limestone, Iowa
Indiana
Missouri
England

Uses

Fossil collecting; whole limestones are made of crinoid bits.

Rock tumbling

Can be tumbled with care.

Did you know?

Crinoid stem pieces were once strung as rosaries called St. Cuthbert's beads.

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