sedimentary

Crinoid Stem Fossil

Class Crinoidea (Sea Lilies)

AI-generated identification · may be incorrect

Hardness: 3 (Calcite); Color: Gray, tan, or white; Luster: Dull to earthy; Crystal structure: Hexagonal/Trigonal (individual ossicles); Appearance: Segmented, cylindrical, often with a central hole.

Hardness: 3 (Calcite)
Color: Gray, tan, or white
Luster: Dull to earthy

Identified June 28, 2026More sedimentary →

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Physical properties

Hardness: 3 (Calcite); Color: Gray, tan, or white; Luster: Dull to earthy; Crystal structure: Hexagonal/Trigonal (individual ossicles); Appearance: Segmented, cylindrical, often with a central hole.

Formation & geological history

Formed during the Paleozoic era (approx. 250-500 million years ago) in shallow marine environments. Fossilization occurs when the calcium carbonate skeletons are buried in lime mud which eventually hardens into limestone.

Uses & applications

Primarily for education, scientific study, and fossil collecting. Historically used for making bead jewelry and buttons.

Geological facts

Crinoids are actually animals (echinoderms) related to starfish and sea urchins, not plants. They are often called 'Sea Lilies' because of their flower-like appearance. In some cultures, fossilized segments are called 'fairy stones' or 'St. Cuthbert's beads'.

Field identification & locations

Identified by cylindrical segments or 'chewed' looking columnals in sedimentary rock. Commonly found in limestone outcrops, riverbeds, and quarries across the Midwestern US and UK.