Feature Gems & Gemology, Spring 2002, Volume 38, No. 1

Identification of Yellow Cultured Pearls from the Black-Lipped Oyster Pinctada Margaritifera

Although the Pinctada margaritifera oyster usually is associated with the black pearls cultured in French Polynesia, it also can produce attractive large yellow cultured pearls, among other colors. An absorption feature at 700 nm can be used to separate these yellow cultured pearls from their more common counterparts produced in the South Seas by the Pinctada maxima. This absorption feature previously has been attributed to the presence of black pigments, and has been reported as an identifying characteristic of black cultured pearls from the P. margaritifera. An additional absorption feature in the UV region, between 330 and 385 nm, is indicative of natural yellow color in cultured pearls from the P. margaritifera.