Rattail is about the same thickness as a rat's tail. Fortunately, the resemblance ends there. It's a finely braided cord with a lovely satin finish.

It comes in lots of beautiful colors and is especially nice for showcasing a single pendant or a few special beads. Because of its thickness, it isn't used to fill an entire necklace with beads — and it's so pretty you wouldn't want to cover it up anyway. To finish, it can be tied directly to a clasp or to itself. To prevent the ends from fraying, you should glue the loose ends.