From elemental mapping to structural insights: A multi-technique investigation into the nephrite from various provenances

Nephrite, a historically significant material in Chinese jade culture, varies in elemental composition and spectroscopic properties based on its geographic origin due to differing mineralization environments. This study aims to address the limitations of traditional methods by employing a multi-technique approach that combines XRF mapping, fiber optic reflectance spectroscopy (FORS), near-infrared spectroscopy (NIR), and synchrotron-based X-ray absorption fine structure (XAFS) analysis, focusing on a comprehensive characterization of Fe to understand the properties of nephrite from various provenances. Our results reveal that while major elements like Si, Mg, and Ca are uniformly distributed, elements such as K, Mn, and Fe show significant variability, with Fe and Mn exhibiting nearly identical distribution patterns. Transparency variations in Qinghai nephrite correlate with Ca distribution. Chromaticity analysis indicates that Fe significantly influences the yellow coloration of nephrite, and NIR spectroscopy shows that Fe content affects spectral characteristics. XAFS analysis provides detailed insights into the valence and coordination environment of Fe, highlighting its role in color variation and spectral shifts. This integrated approach bridges the correlation between elemental composition and distribution, structural properties and visual representation, and its non-destructive advantages could hold great promise for jade research.