Pearls, unlike inorganic minerals such as diamond, ruby, emerald and so on are opaque and their internal characteristics can not be seen using gemological microscope. For their identification (natural, bead-cultured, non-bead cultured) traditionally used X-rays images.
In the past few years in the laboratories of GIA to study the internal structure of the pearls used real-time X-ray microradiography (RTX) or computed X-ray microtomography (μ-CT) and for separating freshwater from saltwater pearls – non-destructive chemical analysis using Energy Dispersive X-ray Fluorescence (EDXRF). These tools and techniques provide only a two-dimensional view of the internal pearl’s structure.
Recently GIA announced acquiring of a new 3-D software which makes it possible virtually to explore, manipulate, extract and reconstruct specific areas of a pearl for analysis. The software also has the potential to analyze other unusual structures within pearls.
More about this new 3-D software and videos with 3-D imaging of pearl inclusions can be found here