sedimentary
Crinoid Stem Fossil
Crinoid columnal (Class Crinoidea)
Hardness: 3-4 (calcite) or 7 (if silicified); Color: Tan, gray, or white; Luster: Dull to earthy; Structure: Cylindrical segments often with a star-shaped or circular central hole (lumen).
- Hardness
- 3-4 (calcite) or 7 (if silicified)
- Color
- Tan, gray, or white
- Luster
- Dull to earthy
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Physical properties
Hardness: 3-4 (calcite) or 7 (if silicified); Color: Tan, gray, or white; Luster: Dull to earthy; Structure: Cylindrical segments often with a star-shaped or circular central hole (lumen).
Formation & geological history
Formed from the mineralized remains of marine animals related to starfish. These segments were part of the stalk that anchored the animal to the sea floor during the Paleozoic era (approx. 250-500 million years ago).
Uses & applications
Commonly used as educational specimens, in decorative stonework, and as a popular item for amateur fossil collectors and jewelry.
Geological facts
Crinoids are often called 'sea lilies' because they look like flowers, but they are actually animals. In some cultures, fossilized stem segments were known as 'St. Cuthbert's beads' and used to make rosaries.
Field identification & locations
Look for small, stacked disc-like wheels or 'button' shapes in limestone. They are extremely common in the Midwest United States and areas with ancient seafloor deposits.
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