| Emerald deposit was discovered first in Davdar, the south of Xinjiang province in 2004,extracted from Carbonate veins with a better quality. On the basis of the previous fully excavation and field research, this paper applies various measurements to analyze mineralogical characteristics and spectroscopic features of Xinjiang Emerald deposit, which are also compared with Colombia Emerald deposit;This paper discusses the formation of Emerald deposit, which supplies demonstrations to the following study of Emerald deposit and mineralogy. In addition, this paper also proposes some advice in terms of the development status of Emerald deposit, which plays a significant role in quality evaluation and development of Xinjiang Emerald deposit.Referring to the mineralogy researches, the ore minerals of Xinjiang emerald deposit are mainly beryl and quartz, and the gangue minerals contain calcite, quartz as well as few Pyrite, Tourmaline, Apatite. The mineral hybrid is Beryl-Calcite-Quartz. Due to better gemological characteristics and better contents of Cr and Fe which are 0.3~1.0% and 0.2~0.8% respectively shown from electron microprobe, Xinjiang Emerald deposit should be of high quality.The study of fluid inclusion shows that Xinjiang Emerald deposit is moderate-high temperature, high salinity fluid because of the fact that its homogeneous temperature range is from 280 ℃ to 340℃ and salinity range is between 14% and 40%, and estimate the average density of ore-forming fluids 0.99 g / cm3. As a result, the emerald deposit belongs to carbonate and pneumato-hydrothermal type in Davdar, Xinjiang. The ore-forming fluid of deposit is characterized by high homogenization temperature, and moderate-high temperature temperature and high salinity.From the study of spectroscopic features, three conclusions can be obtained.First, Raman spectrum confirms that the Raman scattering peaks of stable displacement, and has a stable displacement characteristics, with different directions in the sample, the Spectra shows in differences beryl mineral crystal structure, and its fluid inclusion are in the gas phase was dominated by CO2.Secondly, IR spectra shows that the differences of spectra in different directions of vibration group in Xinjiang emerald crystal structure; CO2 content is higher than Colombia; Based on infrared spectroscopy analysis, type II water is the primary part in emerald deposit, and the vibration intensities of type I and type II water are changed inversely.At last, UV-Vis shows that the UV spectra of Xinjiang emerald samples are consistent with Colombian emeralds, mainly by Cr3+ color caused; Emerald deposit is colored mainly by Cr3+ and slightly by V3+、Fe3+, which is analyzed by UV-Vis.Finally, based on the fluid inclusion characteristics and assistance of spectrum, the formation of Xinjiang Emerald deposit is discussed basically. |
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