fossil

Crinoid Fossil Fragment

Crinoid stem fossil (Echinodermata)

Hardness: 3-4 (calcite), Color: light grey to whitish with darker matrix lines, Luster: vitreous to dull, Crystal structure: trigonal (calcite composition)

Identified August 5, 2026More fossil →

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Physical properties

Hardness: 3-4 (calcite), Color: light grey to whitish with darker matrix lines, Luster: vitreous to dull, Crystal structure: trigonal (calcite composition)

Formation & geological history

Formed in ancient shallow marine environments during the Paleozoic era (particularly Carboniferous and Ordovician periods, approx. 300-500 million years ago) through the accumulation and fossilization of echinoderm skeletal plates.

Uses & applications

Used in fossil collecting, educational displays, and as index fossils for geological dating.

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. Their segmented stems often break apart after death, leaving disk-like fossils colloquially called 'Indian beads' or 'saint Cuthbert's beads'.

Field identification & locations

Easily identifiable in the field by their distinct disk or column-like segments arranged in a stacked, coin-stack pattern or circular imprints on limestone and shale rock surfaces. Commonly found worldwide in limestone formations.

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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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