Fluorescence Characteristic of Fluorite from Namibia

The fluorite produced in Namibia has special colour zones and prismatic inclusions, and its purple cubic ring structure shows strong blue-purple fluorescence under long-wave UV light (365 nm). In order to study the fluorescence characteristics of fluorite from Namibia, the microscopic observation and photography, inductively coupled plasma mass spectrometer (ICP-MS), laser Raman spectrometer, and fluorescence spectrometer were used. ICP-MS testing results of different colour parts of the fluorite sample showed that the concentration of rare earth elements in the purple part was higher than that in the yellow part. In terms of element types, the concentration of rare earth element Ce and Y was higher, and the purple part concentrates twice as much Ce as the yellow part.Raman spectra showed that besides the characteristic peak of fluorite, there are several unstable spectral peaks indicating the rare earth element Er. Combined the photoluminescence spectra with 3D fluorescence spectra, the results showed the luminescence center of Ce³⁺ with very high intensity existed within the excitation wavelength and emission wavelength (Ex/Em) range 310 nm/320 nm and 310 nm/340 nm. According to the testing results of spectra and trace elements, the characteristic blue-violet fluorescence of the fluorite sample from Namibia is produced by Ce.