Unlike the larger types of bivalve or conch shell that were used to make many styles of beads, crinoids are actually fossilized marine animals from the same family as starfish and sea urchins (they’re all echinoderms), and it’s their fossilized stems that are used as beads (see ‘stalk’ / ‘columnal’ designation on the diagram below). Fossilized crinoids are found in the limestone beds and outcrops located throughout what is now the midwestern and southeastern regions of the United States, and represent one of the most commonly found marine fossils in these geographical areas. Crinoid stems are an ideal natural material for use as beads because they are naturally cylindrical in shape, are ridged at even intervals, and have a hollow interior. Furthermore, these fossilized marine stems are found naturally broken into segments of various lengths - or can be intentionally broken into a desired length for bead-making - and they can be polished to a high shine, like the example pictured below which was found during excavations at the site of Chucalissa.
Museum, Chucalissa, "Crinoid Bead" (2022). Artifacts. 71.
Jewelry; Shell Jewelry; Crinoid Bead