So why do mother-of-pearl watch dials have a
link reputation for
link fragility if nacre is so tough It's mostly due to how thin the material has to be sliced in order for it to be used as a watch dial. The strength of nacre like any composite material is thanks to the combination of different properties of different layers and as it thins out it becomes more and more likely to flake or chip when you try to cut or
link etch it.