Gemmological Characteristic of Poudretteite

Poudretteite is a very rare gem variety, and its gemmological and spectral characteristics are rarely reported. In this paper, the gemmological and spectral characteristics and chemical compositions of poudretteite were studied using IR spectroscopy, Raman spectroscopy, LA-ICP-MS and UV-Vis spectrometer in order to provide gemmological data and the detection methods of the rare gem variety. The results showed that the refractive index of the sample is 1.508-1.540, and the relative density is 2.56-2.61. The samples showed inert under the ultraviolet lamp. It is dichromatism of purplish red and light pink. Using IR spectrometer, the absorption peaks of infrared fingerprint location feature are at 1 198、1 054、951、908、797、597、559、506 cm^-1and 486 cm^-1. Raman characteristic absorption peaks are at 1 075、1 044、937、694、551、490、428、316、162 cm^-1and 146 cm^-1. Poudretteite contains a certain amount of Al, P, Ca, Mn, Fe, Rb besides the main amounts of SiO₂, Na₂O, K₂O, B₂O₃. And the 530 nm absorption band of UV-Vis spectrum is mainly caused by Mn.