Gemmological Characteristic of Painite

Painite belongs to a very rare gem variety, and its gemmological characteristics are rarely reported.In this paper, the painite samples were tested by conventional gemmological intruments, infrared spectrometer, Raman spectrometer, EDS energy spectrometer and photoluminescence spectrum technology in order to provide gemmological data of the variety, and improve the detection efficiency. The results showed that the refractive index of painite is beyond the measurement range of gem refractometer and dichroism is obvious. The typical absorption spectrum can be seen under prism spectroscope. It showed inert under LW ultraviolet lamp, and medium to strong yellow green fluorescence under SW ultraviolet lamp. The density is 3.89±0.02 g/cm³, and its Mohs hardness is 7-8 with shell fracture.The results of IR and Raman spectra showed that the characteristic peaks of the sample were related to the vibration of B-O, Al-O, Ca-O and Zr-O, where BO₃^3- and BO₄^5- coexist. The photoluminescence spectra confirmed the existence of electron hole core in the sample. UV-Vis absorption spectra showed that the absorption peaks of the sample were related to the superposition of Ti, V and Fe. The main elements of the sample measured by EDS spectrometer are consistent with the painite formula.