Tahitian Pearls Tahitian Pearls are some of the rarest, most valuable pearls available and have the distinction of being the worlds only naturally black pearl. They come in a wide range of colors including aubergine, eggplant, peacock, silver, purple, pistacio, and more. Tahitian pearls range in size from 9mm to 16mm making them some of the largest pearls available. Tahitian pearls are harvested in French Polynesia from the Pictada Margaratifera oyster. This is one of the largest pearl producing oysters in the world, only exceeded by the South Sea pearl producing Pictada Maxima.