Pearl Testing: Analytical Methods

Pearl testing at times can be very difficult. Experts use a combination of different methods for positive identification. For instance freshwater pearls typically may contain high concentration of manganese, and the high manganese concentration in the specimens can be detected by trace element analysis (Laser Ablation ICP-MS) or by X-ray luminescence methods, which may also help differentiate between freshwater and marine pearls. Provenance determination in a pearl can be achieved by Laser Ablation ICP-MS. Infrared/Raman spectroscopy can also be used to identify modifications of calcium carbonate in pearls to identify the origin of pearl color + naturally colored Tahiti cultured pearls and naturally colored freshwater cultured pearls can be distinguished from their artificially dyed counterparts by Raman spectroscopy. Natural pearls can be differentiated from cultured pearls by different X-radiography tests that reveal the internal structures from a manufactured nucleus. Several radiograms may have to be taken to study varying depths within the pearl's internal growth structures to create a profile. It's not always easy. Lately the application of tabletop X-ray tomograms have improved pearl testing dramatically.