Abstract：Blue hauyne from the Eiffel District, Germany, which belongs to sodalite group mineralogically, is among the rarest gem species. Some crystals represent characteristic orange fluorescence, but few details in its fluorescence spectra were found in the literature. In this paper, more than 20 gem-quality hauyne samples from this region were collected and tested. This batch of hauyne shows body color differing from pale grayish blue to dark blue. Orange fluorescence is only visible under long-wave ultraviolet light (365 nm), while inert under short-wave ultraviolet light (254 nm). Fluorescence spectrometer was applied to describe the photoluminescence phenomenon of samples. A series of fluorescence spectra were collected, including 3D ones. Results showed that the emission band of samples with orange fluorescence centered at 566 and 425 nm. The 566 band, which determines the fluorescence color of the sample, can be excited by light of wavelength range of 300～500 nm, and the optimal excitation wavelength is 397 nm. Furthermore, the 350 nm band can be excited by the 260～325 nm range ultraviolet light, with a best excitation wavelength of 310 nm. High-resolution emission spectrum under 397 nm showed that 566 nm band is accompanied by a large number of stepped fluorescence peak shoulder, which centers at 581, 600, 621, 642, 666 nm respectively. The energy differential of adjacent shoulders is about 0.07 eV. It was observed that the intensity of orange fluorescence was negatively correlated with the depth of blue of the samples, that is, the lighter the blue was, the stronger the orange fluorescence of the sample was. Therefore, it was speculated that the fluorescence peak at 566 nm and its subsequent acromion were related to chromophore S-2.
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