A bead is used instead of a floss stitch to bring out light and other decorative effects (glitter and pizzazz). They are used on such things as costumes, and as stars, wands, jewelry, tiaras. There are many colors, variations, shapes and finishes. Most are round-ish , but bugle beads are cylindrical. They vary greatly in size including: Mill Hill petite beads which are half a millimeter in diameter; Mill Hill seed beads which are one millimeter in diameter; and then there are much larger beads in any shape you like such as stars, hearts, teddy bears, etc. They are usually made of glass or crystal, but could be of wood, metal or plastic. They all have a hole somewhere so they can be attached.
Beads have a long long history with a recent resurgence of the craft of bead decorating and bead making in glass as well as clay, poly-clay, and other substances. Standard glass beads are made on a mandrel, usually working at the torch rather than the furnace. Beads using techniques similar to marble work can be made by blowing a thick hollow tube. Trade beads (as used on American Indian clothing) were made either by blowing and pulling a long thin tube and breaking it into chunks which were smoothed by tumbling or by melting glass on wire and acid removing the wire.