ABOUT PEARL KNOTTED JEWELRY: CHOOSING CLASPS
You can use any type of clasp that you prefer.
However, pearl knotted jewelry is very strongly associated with what are called pearl clasps or safety clasps. These are often marquis-shaped clasps, with a hook like tongue that pushes inside them. If the tongue should somehow come undone and slip out, it would catch on a bar in the clasp, saving you from losing your string of pearls.