Mother of Pearl is the iridescent layer of the shell lining of Pearl oysters and abalone. Found in several natural colors it is often bleached and dyed for bead use. The shimmering & iridescent multi-colored hues of two substances which combined to create the mother of pearl layer are Aragonite, a material which is secreted by the mollusk in plates that are very hard, but also very brittle and a secreted organic material similar to silk to layer between the plates. The result is a strong, flexible Mother of Pearl material that is considered one of the toughest and most beautiful natural materials on Earth.