Eye of Shiva, also called eye of Saint Lucia. It comes from the nacre operculum of conch shells that you can find on some beaches. In the Hindu religion, as an amulet, it represents the third eye of the god Shiva, the eye of wisdom, which sees beyond the obvious. It is also known as the eye of Saint Lucia, who tore his eyes and threw them into the sea. In the Christian religion this amulet protects from the evil eye, attracts prosperity and luck.
Nacre (also called mother of pearl), is an organic-inorganic composite material produced by some molluscs. It is a hard, shining, iridescent material. It is formed in the inner shell of some of the more ancient lineages of bivalves, gastropods, and cephalopods to repair their damaged shells or to cover some objects inside of them. This is used by some pearl pickers, placing certain small items inside molluscs, knowing they will be covered in nacre, forming pearls or other valuable objects. The molluscs that produce the most beautiful nacre are the Abalone and the Nautilida, among other. Nacre is used in medicine for skin care, as an exfoliant.