It is found on the shores of the Mediterranean and therefore on the beaches of Corsica This roller is what we call the eye of St. Lucia. It is in fact eroded the cover of a mollusk.
Many people collect (some are collection) it would have the advantage to bring good luck to those who find it. You can also make purchases on the market or even in shops especially when it is sold mounted with a chain or cord.
The eye of Saint Lucia would have the power to protect its wearer from bad luck (the ochju).
But contrary to what one might think he was more ready for its financial benefits for the view.