fossil

Crinoid Stem Fossil

Crinoid ossicle / stalk segment (Phylum Echinodermata)

Hardness: 3 (calcite); Color: Varies from tan, grey, brown to white; Luster: Vitreous to dull; Crystal structure: Trigonal (calcite composition); Cleavage: Perfect rhombohedral; Specific gravity: 2.71

Hardness: 3 (calcite)
Color: Varies from tan, grey, brown to white
Luster: Vitreous to dull

Identified August 4, 2026More fossil →

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Physical properties

Formation & geological history

Formed from marine organisms known as crinoids (sea lilies) that lived in shallow oceans, primarily during the Paleozoic era (especially Mississippian and Pennsylvanian periods, roughly 350-300 million years ago), where their skeletal segments accumulated in limestone-forming deposits.

Uses & applications

Collected by fossil enthusiasts, used in educational displays, and sometimes cut into lapidary jewelry or ornamental items.

Geological facts

Crinoids are animals, not plants, despite their common name 'sea lilies'. Their segmented stems often break apart after death, leaving behind disc-like fossil fragments commonly referred to by collectors as 'Indian beads' or 'screw stones'.

Field identification & locations

Easily identified by their characteristic round, oval, or star-shaped segments with a central hole or canal. Frequently found weathered out of limestone or shale riverbeds and road cuts worldwide.

Other fossil specimens

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

Crinoid columnal ossicles (phylum Echinodermata)

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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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