A PEARL is a bead on a string that is made from the hard, glossy substance secreted by certain mollusks. It is often used in jewelry and is considered to be a symbol of beauty and wealth. Pearls are formed when an irritant, such as a grain of sand, enters the mollusk's shell and the mollusk secretes a substance to cover the irritant. This process can take several years and the resulting PEARL is unique in shape and color.