Abstract:In this paper, the optical characteristics involving infrared (IR), ultraviolet-visible (UV-Vis) and Raman spectra of aquamarine from Guangdong of China were studied in detail, with chemical compositions determined by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The IR spectral study showed that there were H2O molecules in the structural channels of the studied aquamarine. The Raman spectra further demonstrated that the type II water was dominant and there existed glue injection treatment. For UV-Vis spectra, absorption bands of around 374, 427, 620 and 810 nm mainly associated with element Fe were observed. The LA-ICP-MS analyses showed that the matrix SiO2, Al2O3 and BeO in the aquamarine samples were 67.54 ± 0.13%, 17.48 ± 0.10 % and 13.25 ± 0.07%, respectively. It was worth noting that the concentration of Al2O3 was obviously lower than the theoretical value of 18.99%, demonstrating there were isomorphous substitutions in the studied samples. It was also observed that the total concentrations of Fe+Mg+Mn were about twice as that of TAl-M. The element Fe of high as 6764–8142 μg/g revealed the dual occupancy of Fe ions in Al-O6 octahedra and structural channels. Based on the obtained UV-Vis spectra and element compositions, it can be inferred that the intervalence charge transfer of Fe2+/Fe3+ and electron transitions of Fe2+ simultaneously contributed to the blue color of aquamarine samples from Guangdong, China. Additionally, the concentration relationships of Fe+Mg+Mn with the TAl-M for aquamarine samples from different pegmatite deposits in China assured that aquamarine samples from Guangdong can be directly distinguished via chemical compositions, in particular the concentration characteristics of Fe+Mg+Mn. The effect study of surface smoothness of the studied sample on IR spectrum showed that the number of absorption bands in particular the fingerprint area increased with increasing smoothness but irrespective of the size of analyzing region. This phenomenon can also be observed in UV-Vis spectra of aquamarine. To achieve reliable IR and UV-Vis spectra, the smooth region of the sample was highly recommended for the measurement.