fossil

Crinoid Stem Fossil

Crinoid ossicle (Phylum Echinodermata)

Hardness varies around 3.5 to 4 on the Mohs scale due to the calcite composition; color ranges from grey, brown, to tan; luster is typically dull to vitreous; crystal structure is made of single-crystal calcite per ossicle with characteristic lattice cleavage.

Identified August 4, 2026More fossil →

Explore Crinoid Stem Fossil in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed through permineralization of crinoid columnals (stems) in marine environments, often dating from the Paleozoic era (Ordovician to Permian periods, roughly 250 to 480 million years ago).

Uses & applications

Used primarily by fossil collectors, educational specimens, and occasionally fashioned into jewelry or decorative items.

Geological facts

Crinoids are commonly known as 'sea lilies' because of their plant-like appearance, though they are actually marine animals related to starfish and sea urchins. In some cultures, fossilized crinoid stems were strung together to make jewelry and were historically called 'St. Cuthbert's beads'.

Field identification & locations

Easily identified by their distinctive round or pentagonal disk shapes with a central hole (lumen), often found weathering out of limestone or shale layers worldwide.

Other fossil specimens

See all

Crinoid Stem Fossil in Matrix

Phylum Echinodermata, Class Crinoidea

fossil

Sedimentary Outcrop (Sandstone/Shale)

Sedimentary bedrock formation (variable composition)

sedimentary

Chert with Fossil Brachiopod

Microcrystalline Quartz (SiO2) with Calcitic Brachiopod inclusion

sedimentary

Crinoid Stem Fossils (Indian Beads / St. Cuthbert's Beads)

Crinoid columnal ossicles (phylum Echinodermata)

fossil

Fossilized Crinoid Stem in Limestone

Crinoidea (Class) in Calcium Carbonate (CaCO3) matrix

fossil

Fossiliferous Limestone

Limestone with embedded fossil cross-section

sedimentary