fossil

Crinoid Fossil

Crinoidea (Echinodermata)

Hardness: 3 on Mohs scale (for calcite/limestone matrix); Color: Gray, tan, brown, or white; Luster: Vitreous to dull; Crystal structure: Trigonal (calcite ossicles); Cleavage: Perfect rhombohedral in calcite fragments.

Hardness: 3 on Mohs scale (for calcite/limestone matrix)
Color: Gray, tan, brown, or white
Luster: Vitreous to dull

Identified August 1, 2026More fossil →

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Physical properties

Formation & geological history

Formed in marine environments during the Paleozoic era (particularly the Mississippian and Pennsylvanian periods, around 300-450 million years ago) when skeletal remains of crinoids accumulated on ancient sea floors and were lithified into limestone or shale.

Uses & applications

Primary value is educational, scientific study, and as a collectible specimen for fossil enthusiasts; crinoid-rich limestones are sometimes polished and used as decorative building stone.

Geological facts

Often referred to as 'sea lilies' because of their plant-like appearance, crinoids are actually marine animals related to starfish and sea urchins. Their stem segments are sometimes known colloquially as 'Indian bead stones' or 'St. Cuthbert's beads'.

Field identification & locations

Look for distinctive circular, pentagonal, or star-shaped disks (columnals) embedded in sedimentary rock, particularly limestone outcrops in the Midwestern United States, the UK, and Europe.