tailieunhanh - Aquamarine from Thach Khoan Mining Area in Phu Tho Province, Vietnam

This study was conducted to determine the characteristics of aquamarine. Eight aquamarine samples from granitic pegmatites in Thach Khoan commune, Thanh Son District, Phu Tho Province were investigated by classical gemological methods, Electron Probe Micro-analysis (EMPA) and Laser Ablation – Inductively Coupled Plasma – Mass Spectrometry (LA-ICP-MS) methods, Raman and Fourier transform infrared (FTIR) spectroscopy. | VNU Journal of Science: Earth and Environmental Sciences, Vol. 33, No. 2 (2017) 31-39 Aquamarine from Thach Khoan Mining Area in Phu Tho Province, Vietnam Ly Thuy Duong1,*, Le Thi Thu Huong2 1 Faculty of Geology, VNU University of Science, 334 Nguyen Trai, Hanoi, Vietnam 2 University of Graz, Austria Received 20 January 2017 Revised 16 March 2017; Accepted 28 June 2017 Abstract: Aquamarine is a kind of gemstone having attractive color, valuable and being a potential material in gemological industry. In Vietnam, Thach Khoan area has become a noticeable location to explore aquamarine. However, the researches of aquamarine are still limited. Therefore, this study was conducted to determine the characteristics of aquamarine. Eight aquamarine samples from granitic pegmatites in Thach Khoan commune, Thanh Son District, Phu Tho Province were investigated by classical gemological methods, Electron Probe Micro-analysis (EMPA) and Laser Ablation – Inductively Coupled Plasma – Mass Spectrometry (LA-ICP-MS) methods, Raman and Fourier transform infrared (FTIR) spectroscopy. Results showed that aquamarine presents a low concentration of alkali and high amount of iron. Raman and IR spectroscopy indicate the vibrations of specific bonds including Si-O, Al-O, Be-O, the presence of CO2 and type I H2O in structural channels. By dint of that, we are going to study the potential treatment methods of aquamarine in Vietnam in the following study to enhance its quality as well as value in the global market. Keywords: Aquamarine, Electron Probe Micro-analysis (EMPA), Electron Probe Micro-analysis (EMPA), Raman spectroscopy. 1. Introduction side while the right side illustrates the position of H2O and CO2, a cation in the structural channel. The structure is composed of sixmembered rings of [SiO4]4- - tetrahedrons. These rings stack one above the other along the c-axis forming large structural channel site that is big enough to host many molecules such as H2O, CO2, CH4, NO3 and CO3