fossil

Fossiliferous Limestone (Crinoid stem fossils)

Sedimentary Limestone with Crinoidea ossicles

Hardness: 3-4 (Mohs scale), Color: Dark grey to charcoal, Luster: Dull/Earthy, Crystal Structure: Microcrystalline matrix with calcitic fossil inclusions, Cleavage: None (conchoidal to irregular fracture)

Identified July 2, 2026More fossil →

Explore Fossiliferous Limestone (Crinoid stem fossils) 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) from the accumulation of calcium carbonate and skeletal remains of marine organisms.

Uses & applications

Primarily used as decorative stones, educational specimens for paleontology, and in aggregate for construction or lime production.

Geological facts

Crinoids are also known as 'sea lilies'. The circular and C-shaped patterns on the surface are cross-sections of the animal's segmented stem made of stacked discs called columnals.

Field identification & locations

Identify by its reaction to cold dilute hydrochloric acid (bubbles) and the presence of distinct circular or wheel-like patterns. Common in Great Lakes regions and areas with ancient seabed deposits.

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Fossilized Crinoid Stem in Limestone

Crinoidea (Class) in Calcium Carbonate (CaCO3) matrix

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Fossiliferous Limestone

Limestone with embedded fossil cross-section

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Fossiliferous Limestone with Crinoid stems

Limestone (CaCO3) containing Crinoidea fossils

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Crinoid Fossil in Limestone

Crinoidea fossil (stalk segments) in Calcium Carbonate (CaCO3) matrix

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