sedimentary
Crinoid Columnal
Crinoidea (Class) - Fossilized Columnal Segment
Hardness: 3 (calcified), Color: Gray to tan, Luster: Dull or earthy, Crystal structure: Hexagonal/pentagonal symmetry in the stem cross-section, Cleavage: Rhombohedral (if replaced by calcite)
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Physical properties
Hardness: 3 (calcified), Color: Gray to tan, Luster: Dull or earthy, Crystal structure: Hexagonal/pentagonal symmetry in the stem cross-section, Cleavage: Rhombohedral (if replaced by calcite)
Formation & geological history
Formed during the Paleozoic era (541 to 252 million years ago) in shallow marine environments. These are fossilized sections of the 'stem' of a sea lily, deposited in limestone or shale.
Uses & applications
Paleontological study, educational collecting, and occasionally used in jewelry (known as 'Indian Beads' or 'St. Cuthbert's Beads')
Geological facts
Crinoids are animals related to starfish and sea urchins, not plants, despite their 'sea lily' nickname. Sometimes called 'star stones' or 'fairy coins' by locals.
Field identification & locations
Identified by circular or pentagonal disc shapes with a central hole (lumen) and radiating patterns. Commonly found in limestone outcrops, creek beds, and gravel pits across the Midwestern United States.
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