Origin of Blue-Water Jadeite Jades from Myanmar and Guatemala: Differentiation by Non-Destructive Spectroscopic Techniques

Abstract

Identifying the origin of jadeite jades has become increasingly important from both mineral resource and metamorphic geology perspectives. In this study, we differentiate Myanmar gem-quality blue-water jadeite jades from their Guatemala counterparts via integrating various non-destructive spectrographic techniques, including X-ray fluorescence (XRF), Ultraviolet-Visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. Our results show that the Myanmar blue-water jadeite jades are structurally homogenous with very few impurities, while their Guatemala counterparts commonly have a yellowish margin with scattered white albite and disseminated greenish inclusions of omphacite and (minor) aegirine-augite. Geochemically, the UV absorption spectral data indicate that the Guatemala samples have higher total Fe and Fe2+ contents, but lower Fe3+ content than the Myanmar samples. The Guatemala samples also have higher omphacite content (lower molar Na/(Na+Ca) ratio, as reflected by the lower IR absorption peak wavenumber) and higher heterogeneity (as reflected by the ~680 cm−1 Raman peak shift difference) than that from Myanmar. Major differences are also discovered in the blue series (Myanmar: 0–0.7 cm−1; Guatemala: 1.7–3.2 cm−1) and blue-green series (Myanmar: 6.9 cm−1; Guatemala 13.7 cm−1) of the Raman peak shift difference, which altogether can provide a novel, nondestructive method for distinguishing blue-water jadeite jades from different origins.