A distinguished shell, elegant and well named. One of a few Top-shells here.
I noticed very quickly after finding my first one, that many have serious but healed flaws. These, we think, are caused by crabs attempting predation. True, they are very tough and must be hard to crack, so some come off with disruptions to the shell structure, which seem to heal quite well
There is a white morph Calliostoma zizyphinum, var. lyonsi worth looking for but some normal ones discolour in strong UV (daylight) and also the painted surface wears and fades.