fossil

Crinoid Stem Fossil in Matrix

Phylum Echinodermata, Class Crinoidea

AI-generated identification · may be incorrect

Hardness: 3 (calcite) to 7 (silicified matrix); Color: Gray, tan, buff; Luster: Dull or earthy; Structure: Segmented cylindrical columnals; Specific Gravity: Approx 2.7

Hardness: 3 (calcite) to 7 (silicified matrix)
Color: Gray, tan, buff
Luster: Dull or earthy

Identified July 8, 2026More fossil →

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Physical properties

Hardness: 3 (calcite) to 7 (silicified matrix); Color: Gray, tan, buff; Luster: Dull or earthy; Structure: Segmented cylindrical columnals; Specific Gravity: Approx 2.7

Formation & geological history

Formed through the permineralization of marine animals known as sea lilies. These specimens typically date back to the Paleozoic era (approx. 250-500 million years ago) and formed in shallow, reef-rich prehistoric seas.

Uses & applications

Educational specimens, fossil collecting, lapidary use (such as 'fossil marble'), and geological research.

Geological facts

Crinoids are actually animals related to starfish and sea urchins, not plants, despite their 'sea lily' nickname. Their fossilized stem segments are often called 'Indian beads' or 'St. Cuthbert's beads'.

Field identification & locations

Identify by looking for segmented, bolt-like, or gear-shaped impressions in sedimentary rock. Commonly found in limestone outcrops and along Great Lakes shorelines (e.g., Lake Michigan and Lake Huron).