fossil

Fossiliferous Sandstone with Blastoid / Crinoid Fossil

Echinodermata (Crinoid stem or Blastoid species in Sandstone)

Mohs hardness of matrix approximately 6 to 7 (quartz-dominated sandstone); color is yellowish-brown to tan due to iron oxide/limonite staining; dull to earthy luster; medium-grained gritty texture with prominent calcified or silica-replaced fossil mold/nodule.

Identified July 25, 2026More fossil →

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Physical properties

Formation & geological history

Formed in shallow marine environments during the Paleozoic Era (frequently Mississippian or Pennsylvanian periods, approx. 300 to 350 million years ago) through the deposition and compaction of sand along with ancient marine invertebrate fragments.

Uses & applications

Educational display, paleontology field collection, and study of ancient marine ecosystems.

Geological facts

Crinoids and blastoids were abundant stalked echinoderms that lived attached to the sea floor. Their rounded stem columnals and calyxes often weather out of sedimentary rocks, leaving detailed molds or spheroidal fossils.

Field identification & locations

Identify in the field by looking for yellowish, gritty sedimentary layers containing rounded, segmented, or knobby fossil inclusions; commonly found in river beds, road cuts, and quarries in regions rich in Paleozoic rock exposures.

Other fossil specimens

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Crinoid Stem Fossil in Matrix

Phylum Echinodermata, Class Crinoidea

fossil

Sedimentary Outcrop (Sandstone/Shale)

Sedimentary bedrock formation (variable composition)

sedimentary

Chert with Fossil Brachiopod

Microcrystalline Quartz (SiO2) with Calcitic Brachiopod inclusion

sedimentary

Fossiliferous Limestone

Fossiliferous Calcilutite / Biomicrite

sedimentary

Fossilized Crinoid Stem in Limestone

Crinoidea (Class) in Calcium Carbonate (CaCO3) matrix

fossil

Fossiliferous Limestone

Limestone with embedded fossil cross-section

sedimentary