Clasp means many things. But it can also be meant to mean a brooch, pin, clip, hook or catch. But it can never mean a Zipper.
The general meaning of clasp is "a device, usually of metal, for fastening together two or more things or parts of the same thing e.g. a clasp for paper money; a clasp on a necklace "
So you can use Clasp for anything that performs the same function. However, it most probably won't be clear to the person who uses the specific word like Brooch or buckle.