There are black pearls, indeed. The oyster known as Pinctada margaritifera, which produces Tahitian pearls, is the source of these pearls. The Tahiti islands and other parts of French Polynesia are the main pearl-growing regions. Contrary to their name, Tahitian pearls are available in a variety of hues, such as peacock, grey, silver, and green.
The peculiarities of the mantle of the black-lipped oyster, which secretes the nacre that forms the pearl, are what give Tahitian pearls their distinctive colours. Tahitian pearls have a wide range of colours due to the interaction between light and the nacre structure. The unique and exotic look of these pearls makes them extremely valuable.