Delicate necklace w natural pearls of peacock color, like Tahitian Black Pearls

Delicate style necklace with natural peacock color pearls. They are of high luster and dark blue / purple color. Look like Tahitian black pearls, but can't say for sure. Could be freshwater pearls. See closeup pictures for details. 17" around the neck, with 2" extension. The free hanging part is 2" long. In excellent condition.