Indian bead

Indian bead is a colloquial term for the fossilized stem segments of columnal crinoids, marine echinoderms of the class Crinoidea. The fossils, generally a centimeter or less in diameter, tend to be cylindrical with a small hole (either open or filled) through the axis and can resemble unstrung beads. The fossils are relatively abundant in certain areas, including parts of the American Midwest where they're present in gravel.