A crinoid stem is a fossilized segment of a marine echinoderm, usually found as a stackable, wheel-like disc in limestone. It is identified by its central pentagonal or circular hole and is a staple find for amateur paleontologists in Paleozoic marine strata.

Hardness

3-4

Mohs

Luster

Dull

Transparency

Opaque

fossilcommon

Crinoid Stem

Also: Indian beads, Stone beads, Crinoid ossicles

Hardness: 3-4
Luster: Dull
Transparency: Opaque

Is this crinoid stem?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch crinoid stem with a known reference. Crinoid Stem sits at Mohs 3-4, softer than the next harder reference, harder than the previous one.
2
Name the organism
Decide what left the fossil before worrying about the rock. Organism: Sea lilies (class Crinoidea). Age: Ordovician (about 480 million years ago) to recent.
3
Check the preservation
Preservation: Calcareous ossicles, which fossilize well. That controls the weight, the hardness and how the piece takes a polish.
4
Read the luster
Hold the specimen under a strong light. Luster: dull.
5
Match the color range
Compare against the expected color range: gray, white, tan, brown.

Often found alongside crinoid stem

Minerals reported to co-occur with crinoid stem. Spotting these in float or country rock is a strong cue you are in the right ground.

Calcite
mineral · Mohs 3

All properties

Mohs hardness: 3-4
Density: 2.6-2.7 g/cm³
Colors: Gray White Tan Brown
Luster: Dull
Transparency: Opaque
Rarity: Common
Uses: Collector, Decorative, Educational
Host rock: limestone
Organism: Sea lilies (class Crinoidea)
Age: Ordovician (about 480 million years ago) to recent
Preservation: Calcareous ossicles, which fossilize well

Where rockhounds find crinoid stem

3 mapped spots

Classic worldwide localities

Indiana, USA
Ohio, USA
United Kingdom
Germany
Missouri, USA

Field-hunting tip

Where it forms: limestone. If you start seeing calcite, brachiopods, bryozoans in float, you are in the right ground. In the U.S., the densest reported localities are in Texas, Michigan. Start trip planning there.

Browse 3 U.S. spots for crinoid stem →

Common questions

How do you identify crinoid stem?+

Mohs hardness is 3-4. Organism: Sea lilies (class Crinoidea). Preservation: Calcareous ossicles, which fossilize well. Luster: dull. Common colors include gray, white, tan, brown.

Where is crinoid stem found?+

Notable localities include Indiana, USA; Ohio, USA; United Kingdom; Germany; Missouri, USA.

Can I find crinoid stem in the United States?+

RockHoundR maps 3 crinoid stem rockhounding spots across 2 U.S. states. The top states are Texas, Michigan.

What minerals are found with crinoid stem?+

Crinoid Stem commonly co-occurs with Calcite, Brachiopods, Bryozoans. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does crinoid stem form in?+

Where it forms: limestone. Working float back to the host body is the standard way to chase a fresh occurrence.

What is crinoid stem used for?+

Crinoid Stem is used in collector, decorative, educational.

Find crinoid stem on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.