The filigree is a so-called "returned" decoration which consists of welding one or more gold or silver threads onto a piece of goldsmithery. These can be left smooth or worked in twists, beads or even filed to compose an ornamental pattern. As for granulation, it allows small balls or granules to be added by welding. Watermarks consisting of two braided threads and a single granulation form the rich ornamentation of the upper part of the pyxis of Saint-Omer.