STRUCTURAL CHARACTERISTICS OF WATER IN TURQUOIS
Li Xin'an;Wang Puya;Zhang Huifen Institute of Geochemistry, Academia Sinica
Turquois, due to its bright blue-green color, is a high grade jade material.Quite an amount of water is present in the structure of quituois. Chemicalanalysis shows that turquoises showing different colors contain varying amo-unts of water from 15 to 20%. Little work has been done on the structurestate, structural characteristics of water and its influence on the color ofquituois.Presented in this paper are detailed results of the study on the structuretype, existing state and thermo-stability of water in turquois by NMR techni-ques, indicating that there are three structural types of proton in turquois,arranged in hydroxyls, crystalline water and adsorped water, respectively.As for the hydroxyls,four different structural positions may be distinguished.Obviously,a different kind of water is different in thermo-stability.Water lossfrom quituois due to heat follows the order: OHH_2O_(cry)H_2O_(ads)NMR analysis puts insight into the structural characteristics of water inquituois. Also, infrared spectroscopy and thermal expansion experiments havelent strong support. Our practise shows that NMR technique is a powerfulmethod in studying gem structures.
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