Abstract：This paper studies a kind of seed material gemstone called “blue Hotan jade” with sparse output and high marketing price. Due to the deficiency of previous research and standardized naming, its business name is confused in the trading market. Hydrostatic weighing method determines The relative density of 3.85 g·cm-3. Only the white mineral part shows orange fluorescence under the long-wave ultraviolet lamp. Through microscopic observation, straight a blue-white color zone, coniform blue-white color zone, irregular blue zone and many white vein minerals can be seen. Through observation by orthogonal polarization and differential interference, it is determined that the vein minerals are different from the substrate and formed after the substrate. It is determined that the infrared absorption peaks of blue substrate and white zone mineral are located at 812/817, 652/655 and 613/620 cm-1, which conforms to the characteristic vibration of corundum; 3 019, 2 950, 2 129, 1 990, 1 121, 1 030, 799, 733, 648, 598 cm-1 absorptions of vein minerals conform to the characteristic vibration of diaspore. The absorption spectra of different parts of the sample were measured by micro UV-VIS-NIR spectrophotometer, in which no obvious absorption was found in the white color zone; 429 and 453 nm absorption caused by Fe3+ d electron transition 6A1→4E, 4A1(4G) and 1 810, 2 030 and 2 235 nm absorption caused by OH vibration were found in the vein minerals; 421/418, 562/566, 702/709 and 868/889 nm absorption caused by Fe3+ d electron transition 6A1→4E, 4A1(4G), Fe2+-Ti4+ ion pair charge transfer and Fe2+-Fe3+ ion pair charge transferwere observed on the blue substrate. As the color deepens, the blue region 421 nm absorption occurs blue shift, 500～900 nm absorption occurs red shit, and the absorption peak integral area increases according to the quantitative analysis of the XRD pattern, sapphire accounts for about 66. 9%, and diaspore about 33.1%. According to the national standard named jewellry and jade (GB/T 16552—2017), it is recommended to be named Diaspore-Sapphire.
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