Unravelling the luminescence spectrum of novel ceramic nucleus cultured pearl and the cause of its strong luster.

The newly developed ceramic-nucleus pearls employ ceramic materials for cultivation, differentiating from the traditional seashell-based nuclei. This innovation yields a product that resembles Akoya pearls but exhibits superior luster. In this manuscript, Energy Dispersive X-ray Fluorescence (EDXRF), three-dimensional (3D) fluorescence spectroscopy, photoluminescence (PL) spectroscopy, UV-visible (UV-vis) spectroscopy, Fourier Transform Infrared (FTIR) Spectroscopy, and Scanning Electron Microscopy (SEM) were used to thoroughly analyze the mother oyster of these ceramic-nucleus pearls. The test results suggest that these ceramic pearls may originate from the same mother oyster species as Akoya pearls, making them difficult to distinguish through visual observation. Nonetheless, the presence of abnormal characteristic peaks of Zr in EDXRF testing and additional weak emission centers observed at excitation/emission (E/E) wavelengths of 292/346 nm in the 3D fluorescence spectra provide crucial evidence for differentiating between the two types of pearls. Furthermore, SEM analysis demonstrated that the nucleus and aragonite layer of the ceramic pearls are tightly bonded, with the aragonite layer that is distributed evenly and regularly. This structural feature may contribute significantly to the enhanced luster observed in ceramic pearls. The advent of ceramic-nucleus pearls opens new possibilities for improving the luster of cultured pearls, potentially revolutionizing the industry.