Trace Element Analysis by PIYE and ICP-AES of Raw Material and Ancient Serpentine Artifacts from China.

This work mainly talks about serpentine mineral with the aim to explore the possible raw materials sources of ancient serpentine artifacts by trace element content analysis. The major and trace elements of serpentine samples from several typical deposits in China were nondestructively determined by external-beam proton-induced X-ray emission (PIXE). For comparison, trace element concentrations were destructively measured by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The results showed the trend of the trace element contents of serpentine jade obtained by the two methods have preferably coherence, which indicate that the nondestructive technique of PIXE can be applied to trace element analysis of serpentine. The relationship between trace element contents and serpentine formation mechanism was discussed. The difference of the trace elements contents in these serpentine minerals is obvious. It can be used to distinguish the different kinds of serpentine formed by different mechanisms. A low amount of Ni and almost no Cr and Co were found in type I serpentine group mineral, whereas significant amounts of Cr, Co and Ni were found in Type II serpentine group mineral. The chemical composition of 18 ancient serpentine artifacts were analyzed by PIXE, they were unearthed from 14 sites and tombs in provinces of Zhejing, Jiangsu, Henan, Anhui and Hubei and dated from Neolithic Age to the Warring States Period (4585 BC­231 BC). By comparing the trace element contents between ancient serpentine artifacts and two kinds of serpentine samples, the provenance of ancient serpentine artifacts were preliminarily inferred. It is beneficial to try to explore the possible raw material of ancient serpentine artifacts based on the relationship between the trace element contents and serpentine formation mechanism in this article.

[Coloration mechanism and chromaticity of Xiuyan Jade of China].

The coloration mechanism of Xiuyan Jade was studied with the chemical composition, valance and coordination states of transition metal ions. The result of inductively-coupled plasma atom emission spectrometer (ICP-AES) indicated that there are little other transition metal elements except for iron and manganese. Electron paramagnetic resonance (EPR) revealed that Fe3+ ions locate at both octahedral sites and tetrahedral sites. Optical absorption spectrum (OAS) showed the presence of Fe2+ and Fe3+ ions. Moreover, depending on the results of OAS, Fe2+ ions determine the green color of Xiuyan Jade, while the coexistence of Fe3+ and Fe2+ ions introduces the yellow color of Xiuyan Jade. The chromaticity coordinate was calculated according to diffuse reflectance spectrum. The result demonstrated that chromaticity coordinates can be used to quantitatively distinguish Xiuyan Jade with similar color, which can provide a scientific reference for the evaluation of the value of Xiuyan Jade.