Turitella is a type of limestone with crinoid fossils embedded in it. Crinoids are a type of sea creature that lived long ago, and all that remain these days are fossils. When I was in college, I was comissioned to take several crinoid fossils that had closed tightly in death, envision them open in their living state, and draw them for a publication entitled Paleoecology of Hardground Encrusting and Commensal Crinoids, Middle Ordovician, Tennessee, by Dr. Thomas Guensburg (who was a professor of Earth Sciences at Southern Illinois University at Edwardsville, and a good friend of mine). Here are some examples of what crinoids looked like.
Crinoids consisted of a crown, arm-like structures, and a stalk or stem. In Turitella, you can often see segments of the stalks. Our Turitella Point pendants can often show spectacular samples of crinoid stalk fossils. Our Turitella Chip Beads show the fossils somewhat less clearly, but you can usually find a few good samples in a single bag.
This is a close-up of the main crinoid components found in Turitella: the stalk and crown.