Saltwater pearls are produced by oysters found in the sea and generally only a single pearl per shell is found. They originate from places such as Thailand, Australia, Indonesia, Tahiti, and the Philippines. South Sea pearls, Tahitian pearls, and Akoya pearls all belong to the saltwater pearl family.
Among the larger saltwater varieties, South Sea pearls will typically reach 11 - 14mm in diameter. In some cases they can grow much larger. Part of the desirability of South Sea pearls may be the iridescent gold and silver hues they acquire from the silver-lip and gold-lip molluscs in which they grow.
Tahitian pearls are cultured in black-lip oysters. They have a darker nacre with surface iridescence and overtones of peacock, blue, green, purple and gold.