A bone folder, bonefolder, or folding bone is a dull-edged hand tool used to fold and crease material in crafts such as bookbinding, cardmaking, origami, and other paper crafts that require a sharp crease or fold. The tool was also used when correspondence by letter writing was more formal and an art. They are often made from the leg bone of a cow, deer, or similar animal, or ivory. Alternatives made from plastic now exist; however, those made from bone may be less likely to leave residue on the workpiece.