fossil

Fossilized Crinoid Stem in Pebble

Crinoidea (Class) preserved in calcite/matrix

Hardness: 3 (calcite matrix) to 6.5 (chert matrix); Color: Gray pebble with white ladder-like or segmented fossil structure; Luster: Dull to earthy; Cleavage: None (in matrix); Density: 2.6 - 2.7 g/cm³

Hardness: 3 (calcite matrix) to 6
Luster: Dull to earthy

Identified July 24, 2026More fossil →

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Physical properties

Formation & geological history

Formed during the Paleozoic Era (approx. 300-450 million years ago) in shallow marine environments. The calcified segments of a crinoid's stem (sea lily) were buried in marine sediment, mineralized, and later water-worn into a smooth beach pebble.

Uses & applications

Educational purposes, fossil display, rockhounding collections, and decorative lapidary art.

Geological facts

Crinoids are marine invertebrates related to sea stars and sea urchins, often called 'sea lilies' because of their plant-like appearance. Disconnected crinoid stem segments are historically known as 'Saint Cuthbert's beads' or 'star stones'.

Field identification & locations

Identified by the distinct ladder-like pattern formed by the cross-section or longitudinal view of stacked stem ossicles (columnals). Commonly found along limestone coasts, riverbeds, and gravel deposits worldwide, particularly in North America and the UK.

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Crinoid Stem Fossil in Matrix

Phylum Echinodermata, Class Crinoidea

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Sedimentary Outcrop (Sandstone/Shale)

Sedimentary bedrock formation (variable composition)

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Chert with Fossil Brachiopod

Microcrystalline Quartz (SiO2) with Calcitic Brachiopod inclusion

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Fossiliferous Limestone

Fossiliferous Calcilutite / Biomicrite

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Fossilized Crinoid Stem in Limestone

Crinoidea (Class) in Calcium Carbonate (CaCO3) matrix

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Fossiliferous Limestone

Limestone with embedded fossil cross-section

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