sedimentary
Fossiliferous Limestone with Crinoid Stem Impression
Calcium Carbonate (CaCO3) matrix with Crinoidea fossil
Hardness: 3-4 (matrix); Color: Light gray to tan/beige; Luster: Dull or earthy; Structure: Bioclastic/Fragmental; Presence of a cylindrical, segmented impression (crinoid columnal stem).
- Hardness
- 3-4 (matrix)
- Color
- Light gray to tan/beige
- Luster
- Dull or earthy
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Physical properties
Hardness: 3-4 (matrix); Color: Light gray to tan/beige; Luster: Dull or earthy; Structure: Bioclastic/Fragmental; Presence of a cylindrical, segmented impression (crinoid columnal stem).
Formation & geological history
Formed in shallow marine environments where skeletal debris (calcium carbonate) accumulated over millions of years. This specimen likely dates from the Paleozoic era (e.g., Carboniferous or Mississippian periods).
Uses & applications
Primarily used for geological education, collecting, and construction or agriculture when found in mass quantities. Small specimens are valued by amateur fossil hunters.
Geological facts
Crinoids are known as 'sea lilies' because they resemble plants, but they are actually echinoderms related to starfish and sea urchins. Their segmented stems are one of the most common fossils found in Midwest and Appalachian limestone deposits.
Field identification & locations
Identify in the field by looking for a 'screw-thread' or stacked disc impression in sedimentary layers. Commonly found in limestone outcrops, riverbeds, and quarries across the central United States and Europe.
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