Bones are a type of handle, and are created by decomposing corpses. They can be sharpened to do a bit more damage, but this is not very much, and they are crafted to the same things as the normal bone. The bone is a typical long bone like a femur and nobody knows why you never get other bones (other than skulls if you specify it)
DMG: 4 (2 vs wall)
DMG: 5 (2 vs wall)
See Handle for a list of things the bone can craft into.