fossil

Crinoid Stem Fossil

Crinoid columnal (Echinodermata)

Hardness: 3 on Mohs scale (for the calcite); Color: Light gray to brownish-gray; Luster: Vitreous to dull; Crystal structure: Trigonal (calcite plates); Cleavage: Perfect rhombohedral in calcite; Specific Gravity: 2.71

Hardness: 3 on Mohs scale (for the calcite)
Color: Light gray to brownish-gray
Luster: Vitreous to dull

Identified July 31, 2026More fossil →

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Physical properties

Formation & geological history

Formed in marine environments during the Paleozoic era (particularly the Carboniferous period) when crinoids (sea lilies) lived on the ocean floor and their segmented stems broke apart upon death, becoming fossilized in limestone or shale.

Uses & applications

Used primarily by fossil collectors, educational displays, and occasionally in lapidary work for jewelry.

Geological facts

Crinoids are marine animals related to starfish and sea urchins. In some cultures, fossilized crinoid stems are known as 'St. Cuthbert's beads' or Indian bead stones and were historically strung into necklaces.

Field identification & locations

Easily identified by their circular, pentagonal, or oval shape with a central hole (lumen), often called 'star stones' or 'screw stones' in the field. Found globally in marine sedimentary rock formations.