Cultured pearls can be from saltwater or freshwater mollusks. Pearl farmers introduce a shell bead into the oyster or mussel and the mollusk deposits layers of nacre around the bead. Many people use the term cultured pearls to refer only to pearls produced from saltwater oysters. However, the process to make freshwater pearls is the same. The correct usage is freshwater cultured pearls or saltwater cultured pearls.