fossil
Crinoidal Limestone
Fossiliferous Limestone containing Crinoid stem fragments (Echinodermata)
Hardness 3-4 (Mohs), Light gray to buff matrix, Dull luster, Effervesces with dilute hydrochloric acid, Contains circular and rod-like fossil inclusions.
Identified More fossil →
Explore Crinoidal Limestone in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness 3-4 (Mohs), Light gray to buff matrix, Dull luster, Effervesces with dilute hydrochloric acid, Contains circular and rod-like fossil inclusions.
Formation & geological history
Formed in warm, shallow marine environments through the accumulation of calcium carbonate and biological remains during the Paleozoic era (approx. 250-500 million years ago).
Uses & applications
Crushed for aggregate in construction, used in lime production, and highly valued as educational and decorative fossil specimens.
Geological facts
Crinoids are also known as 'sea lilies,' though they are animals related to starfish rather than plants. The disc-shaped sections of their stems are often called 'Indian beads.'
Field identification & locations
Commonly found in riverbeds and limestone outcrops in the Midwest USA (e.g., Ohio, Indiana, Kentucky). Identified by the presence of small, donut-shaped or rectangular fossil segments embedded in the rock.
More like this
Other fossil specimens
Crinoid Stem Fossil in Matrix
Phylum Echinodermata, Class Crinoidea
fossil
Sedimentary Outcrop (Sandstone/Shale)
Sedimentary bedrock formation (variable composition)
sedimentary
Fossiliferous Limestone
Fossiliferous Calcilutite / Biomicrite
sedimentary
Fossiliferous Limestone
Biogenic Limestone with Brachiopod/Crinoid fragments
sedimentary
Fossilized Crinoid Stem in Limestone
Crinoidea (Class) in Calcium Carbonate (CaCO3) matrix
fossil
Fossiliferous Limestone
Limestone with embedded fossil cross-section
sedimentary