Identification Method of Glue-Filled Aquamarine

As aquamarine becomes more and more popular with consumers, a large number of aquamarines that have been filled with glue began to appear in the market. This treatment improves the durability and appearance of aquamarine to a certain extent, but it still needs to be marked as "treatment" during trade. This article uses conventional gemmological testing methods, Fourier transform infrared spectrometer, and laser Raman spectrometer to analyze and study the identification method of glue-filled aquamarine in depth. The refractive index of the glue-filled aquamarine is 1.577 to 1.583, which is in the normal range, but the relative density is low(2.55-2.70). Microscopic magnification inspection can often see the residue of the filling of the surface, and there is a difference in luster of the crack between the filler and the main body, and the bubbles produces by glue injection and blue-purple flash effect can be seen in the depth of the fracture. Under ultraviolet fluorescent lamps, the filler mostly emits a distinct blue-white fluorescence along the fissure or pit. The infrared spectrometer shows the telescopic vibration band of methylene (—CH₂—) and methyl (—CH₃—) at 2 872, 2 930, 2 962 cm^-1 and methyl (—CH₃—) and the absorption peak caused by the benzene ring at 3 032, 3 058 cm^-1 and weak absorption peak at 4 065 cm^-1. Raman spectra showed that the filler mainly appeared two sets of Raman displacement combination at 1 113, 1 186, 1 608 cm^-1 and 2 870, 2 924, 3 066 cm^-1, and Raman spectrum peaks at the 2 924 cm^-1 and 2 870 cm^-1are attributed to the stretching vibration of methyl (—CH3—) and methylene (—CH2—) and the rest of the Raman shift are due to the benzene ring. Both blue flash and ultraviolet fluorescence can be used as the most intuitive and convenient detection methods for glue-filled aquamarine, and infrared spectroscopy and Raman spectroscopy testing technology can provide a strong scientific basis for identifying glue-filled aquamarine.