Most of the “golden” South Sea cultured pearls in a single strand were found to exhibit unusual brownish orange fluorescence to long-wave UV radiation and atypical absorption features at 405 nm and 558 nm. On the basis of these features and visual examination, 33 of the 35 cultured pearls were identified as color treated. This study demonstrates how atypical absorption features, particularly in the blue region of the spectrum, can be used to positively identify color treatment, even in the presence of the 330–385 nm UV absorption feature characteristic of natural-color “golden” pearls from the Pinctada maxima mollusk.
