In their book "Bijoux du Maroc - Du Haut Atlas à la vallée du Draa" ("Jewelry of Morocco - From the High Atlas to the Draa Valley"), Jacques et Marie-Rose Rabaté give many detailed informations about the subject. From one valley to the other, one tribe to the other, styles, manufacturing processes and materials are differing. In the following text are exerpts from this book.
About the fibula, for instance, Rabaté write: "The most caracteristic jewel, in a country where women all the time wore draped cloths, is the fibula. It is provided with a kind of spine which is surrounded with a ring; the two parts of the cloth to be joined, are perforated by the spine, and then the ring will be turned, so that the cloth cannot slip."