sedimentary

Crinoid Stem Fossil (in Chert or Limestone Matrix)

Crinoidea (Class) - Calcium Carbonate (CaCO3)

AI-generated identification · may be incorrect

Hardness: 3-4 (calcite) to 7 (if silicified); Color: Tan, grey, or off-white; Luster: Dull to earthy; Structure: Cylindrical segments with central 'pith' or hole; Cleavage: Rhombohedral (in fossil segments).

Hardness: 3-4 (calcite) to 7 (if silicified)
Color: Tan, grey, or off-white
Luster: Dull to earthy

Identified June 23, 2026More sedimentary →

Explore Crinoid Stem Fossil (in Chert or Limestone Matrix) in the encyclopedia →

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Physical properties

Formation & geological history

Formed in shallow marine environments during the Paleozoic era (approx. 250-500 million years ago) through the accumulation of skeletal remains on the ocean floor, later lithified into rock.

Uses & applications

Used primarily for educational purposes, paleontological study, lapidary work (when silicified), and as common collector items.

Geological facts

Crinoids are also known as 'Sea Lilies.' Despite their plant-like appearance, they are marine animals related to starfish and sea urchins. Their fossilized segments are often called 'Indian beads' or 'St. Cuthbert's beads.'

Field identification & locations

Identify by looking for stacked, disc-like buttons or small star-shaped holes in cross-sections. Commonly found in limestone quarries, creek beds, and road cuts in the Midwestern US and UK.