Atypical Bead Cultured Pinctada maxima Pearls Nucleated with Freshwater Non-Bead Cultured Pearls


The 12 white and “golden” South Sea cultured pearls (Pinctada maxima) of various shapes and sizes examined in this study. Although their external appearances are similar to saltwater bead and non-bead cultured (NBC) pearls, 11 of them are atypical bead cultured (aBC) pearls formed by inserting freshwater non-bead cultured pearls as nuclei into saltwater hosts. Photo by Nuttapol Kitdee.

White and yellow “golden” South Sea cultured pearls are typically nucleated with freshwater shell beads. However, shell beads are not the only material used as nuclei. In this study, freshwater non-bead cultured pearls were inserted as nuclei in saltwater hosts. Researchers from GIA’s Bangkok laboratory performed spectroscopy (UV-Vis, PL, and Raman), LA-ICP-MS chemical analysis, and microradiography and X-ray luminescence examination on 12 samples. Two samples were cut in half to further analyze their internal structures.
 
The results are available in a study titled "Atypical Bead Cultured Pinctada maxima Pearls Nucleated with Freshwater Non-Bead Cultured Pearls." The authors concluded that standard pearl testing methods permit the straightforward identification of such aBC pearls, and the ability to obtain more data from the pearls cut in half is a very useful method for further scientific examination.