Rock Identifier
Crinoid Stem Fossil (Crinoidea (Class)) — fossil
fossil

Crinoid Stem Fossil

Crinoidea (Class)

AI-generated identification · may be incorrect

Segmented cylindrical structure, often called 'columnals'. Hardness: 3 (calcite-based). Color: Grey to tan. Luster: Dull to earthy. Structure: Disc-like stack.

Hardness
3 (calcite-based)
Color
Grey to tan
Luster
Dull to earthy
Identified More fossil →
Explore Crinoid Stem Fossil in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App StoreGoogle Play

Physical properties

Segmented cylindrical structure, often called 'columnals'. Hardness: 3 (calcite-based). Color: Grey to tan. Luster: Dull to earthy. Structure: Disc-like stack.

Formation & geological history

Formed from the skeletal remains of marine echinoderms known as sea lilies. These calcified stems were deposited in shallow sea beds primarily during the Paleozoic era (approx. 300-500 million years ago).

Uses & applications

Collectibles, educational specimens, and occasionally used in jewelry or inlay work. Important for stratigraphic dating.

Geological facts

Crinoids are actually animals related to starfish, not plants. Their stem segments are so common in some limestone layers that they are referred to as 'encrinal limestone'.

Field identification & locations

Identify by looking for stacked, button-like rings or a central hole (lumen) in the cross-section. Commonly found in limestone outcrops and riverbeds in the Midwest US and UK.

More like this

Other fossil specimens

Probable fossil-bearing rock or mineral concretion (Unidentified carbonate-rich concretion with a possible fossil inclusion) — fossil

Probable fossil-bearing rock or mineral concretion

Unidentified carbonate-rich concretion with a possible fossil inclusion

fossil
Likely fossil oyster shell (Fossilized bivalve shell; exact species cannot be identified from the image) — fossil

Likely fossil oyster shell

Fossilized bivalve shell; exact species cannot be identified from the image

fossil
Crinoid Stem Fossil in Matrix (Phylum Echinodermata, Class Crinoidea) — fossil

Crinoid Stem Fossil in Matrix

Phylum Echinodermata, Class Crinoidea

fossil
Fossiliferous limestone (likely a crinoidal or shell-fragment limestone) (Bioclastic limestone, composed chiefly of calcite (CaCO₃)) — sedimentary

Fossiliferous limestone (likely a crinoidal or shell-fragment limestone)

Bioclastic limestone, composed chiefly of calcite (CaCO₃)

sedimentary
Fossil oyster shell (Oyster (family Ostreidae); shell composed chiefly of calcite (CaCO₃)) — fossil

Fossil oyster shell

Oyster (family Ostreidae); shell composed chiefly of calcite (CaCO₃)

fossil
Weathered fossil bone fragment (identification uncertain) (Fossilized bone; exact taxon and mineral composition cannot be determined from the image) — fossil

Weathered fossil bone fragment (identification uncertain)

Fossilized bone; exact taxon and mineral composition cannot be determined from the image

fossil