fossil

Fossils in Limestone (Crinoid / Marine Invertebrate Fossil)

Fossiliferous Limestone (containing Crinoidea / Brachiopoda)

Hardness: 3-4 on Mohs scale (calcite matrix). Color: Dull grey, tan, reddish-brown, and greyish-blue tones. Luster: Earthy, dull, non-metallic. Texture: Rough, granular matrix with distinct circular and elongated impression fossils. Cleavage: Poor, irregular to subconchoidal fracture.

Hardness: 3-4 on Mohs scale (calcite matrix)
Color: Dull grey, tan, reddish-brown, and greyish-blue tones
Luster: Earthy, dull, non-metallic

Identified July 27, 2026More fossil →

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Physical properties

Formation & geological history

Formed in shallow, warm marine environments where marine invertebrates like crinoids, brachiopods, or mollusks died and were buried under layers of calcium carbonate sediment. Over geological timescales (often Devonian to Carboniferous periods), compaction and cementation formed fossiliferous limestone.

Uses & applications

Used primarily as an educational or display specimen for fossil collectors. In larger quantities, fossiliferous limestone is used as building stone, decorative masonry, and crushed stone aggregate.

Geological facts

Crinoids, often called 'sea lilies', are marine animals related to starfish and sea urchins, not plants. Their stem segments are among the most common fossils found in Paleozoic sedimentary rocks worldwide.

Field identification & locations

Look for small, button-like or donut-shaped circular indentations (crinoid columnals) or shell fragments imbedded in fine-grained grey or beige limestone. Commonly found in stream beds, quarries, and coastal cliffs in limestone-rich regions. Collectors can test with dilute acid (HCl), which fizzes on the calcite matrix.

Other fossil specimens

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Crinoid Stem Fossil in Matrix

Phylum Echinodermata, Class Crinoidea

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Sedimentary Outcrop (Sandstone/Shale)

Sedimentary bedrock formation (variable composition)

sedimentary

Chert with Fossil Brachiopod

Microcrystalline Quartz (SiO2) with Calcitic Brachiopod inclusion

sedimentary

Fossilized Crinoid Stem in Limestone

Crinoidea (Class) in Calcium Carbonate (CaCO3) matrix

fossil

Fossiliferous Limestone

Limestone with embedded fossil cross-section

sedimentary

Fossiliferous Limestone

Fossiliferous Calcilutite / Biomicrite

sedimentary