Crinoid Stem Columnal Fossil (or Segmented Crinoid Stem)
Crinoid indet. cf. columnals • Body fossil, invertebrate marine fossil (specifically fossilized crinoid columnals/stem fragments)
Geological Period
Carboniferous (or Ordovician to Permian, commonly Paleozoic)
Estimated Age
300 to 350 million years old
Preservation Type
Permineralization and calcitic replacement
Condition Assessment
Fair to Good, showing moderate surface weathering and abrasion with rounded edges from transport, though segment patterns remain clearly visible
Taxonomic Classification
Phylum Echinodermata, Class Crinoidea, Order Articulata (or fossil equivalents), Family undetermined, Genus undetermined
Morphological Description
Elongated, cylindrical column or stem fragment showing distinct regular segments or plates (columnals) stacked vertically, creating a segmented or grooved external texture along the length of the fossil.
Rock Matrix
Limestone and weathered calcareous sediment matrix with minor quartz sand grains
Formation & Location
Paleozoic marine limestone formations globally, commonly found in the Midwest United States (such as the Burlington-Keokuk Formation) and parts of Western Europe
Size & Dimensions
Approximately 2 to 3 cm in length and under 1 cm in diameter, consistent with typical small crinoid stem fragments
Value & Rarity
Estimated Market Value
1 to 5 USD
Auction Estimate
5 to 15 USD as part of a lot
Rarity Assessment
Common, widely distributed globally in Paleozoic marine deposits
Scientific Significance
Demonstrates the abundance of crinoids ('sea lilies') in ancient Paleozoic shallow marine environments and helps paleoecologists reconstruct ancient carbonate platform ecosystems
Preparation Recommendations
Gentle mechanical cleaning with a soft brush and water to remove surface dirt; no complex conservation or aggressive acid preparation is necessary; store in a dry, stable environment
Notable Features
Clearly defined stacking rings (discs) showing the characteristic modular columnal architecture typical of crinoids, often popularly referred to as 'Indian beads' or 'screw stones'