Imperial topaz is a kind of precious topaz,whose colour is orange or pink-orange.There has been a wealth of research on topaz,but few studies have been found to systemati-cally characterize the gemmological and spectroscopic characteristics of imperial topaz.In this study,the gemmological and spectral characteristics of imperial topaz were systematical-ly studied by conventional gemmological testing methods,laser ablation inductively coupled plasma mass spectrometer(LA-ICP-MS),Raman spectrometer,infrared spectrometer,three-dimensional fluorescence spectrometer,ultraviolet-visible spectrometer,photolumines-cence spectrometer.The refractive index of imperial topaz samples is 1.629-1.641,higher than that of blue or colourless topaz.The fluoresce of imperial topaz is yellow or orange un-der long wave ultraviolet light and it has medium degree of orange-light orange pleochroism.The infrared spectrum and Raman spectrum of imperial topaz are basically consistent with the standard infrared spectrum and Raman spectrum of topaz.The three-dimensional fluores-cence spectrum shows that there are two main fluorescence centers of imperial topaz,which are located at 424 nm(λex)/686 nm(λem)and 582 nm(λex)/686 nm(λem).Some samples also have a subfluorescence center in the yellow or orange regions of the emission wavelength.The electronic transition of Cr4+produces absorption in the UV-Vis spectrum around 420 nm and 530 nm,resulting in the distinctive orange colour of imperial topaz.
维普
万方数据