Nina Gong’s scientific contributions

What is this page?


This page lists works of an author who doesn't have a ResearchGate profile or hasn't added the works to their profile yet. It is automatically generated from public (personal) data to further our legitimate goal of comprehensive and accurate scientific recordkeeping. If you are this author and want this page removed, please let us know.

Publications (1)


Figure 3. The EPMA test area of the sample. (a) Partial enlarged photo of the sample: the main study area is marked by the red dooed lines; (b) mineral micrograph of the sample; (c) orthogonal polarizing micrograph of the sample; (d) the tested points.
Figure 4. In situ element LA-ICP-MS mapping of the sample. (a-c) major element Si, Mg, and Ca; (d-j) first transition-metal elements Ti, V, Cr, Mn, Fe, Ni, and Cu; (k) test region of the sample.
Chemical composition of the sample, as determined by EPMA. Oxides (wt%).
The micro-XRF analysis results of the ten selected points of the sample (wt%).
Color Origin of Greyish-Purple Tremolite Jade from Sanchahe in Qinghai Province, NW China
  • Article
  • Full-text available

August 2023

·

64 Reads

·

4 Citations

Minerals

Nina Gong

·

Chaowen Wang

·

Shuai Xu

Greyish-purple tremolite jade has become well known in the past few years, and the origin of its color has attracted the attention of gemologists. In this study, FT-IR spectra, EPMA, EPR spectra, micro-XRF, UV–Vis–NIR spectra, and LA-ICP-MS in situ mapping were analyzed to investigate the chromophore elements. The study sample was chosen from the Sanchahe mine, Qinghai Province, NW China, which has the typical characteristics of a gradual color change. The FT-IR and EPMA results revealed that the mineral composition of the dark and light greyish-purple regions of the sample are primarily composed of tremolite. UV–Vis–NIR spectra demonstrated that the greyish-purple color is mainly due to strong absorptions at 560 nm and 700 nm and weak absorption at 745 nm in the visible range. The EPR spectra presented ~3400 G six hyperfine lines resulting from the hyperfine interactions of the unpaired electron with the Mn2+ nucleus in the octahedral site. The UV–Vis–NIR and EPR spectra analyses demonstrated that Mn2+ is the origin of the purple color. A comparison of the major elements in the light and dark regions indicated that the chromogenic elements have strong positive correlations with Mn, Cu, and Fe. LA-ICP-MS mapping used to analyze the first transition metals indicated possible positive correlations between the greyish-purple color and the trace chromogenic elements. This suggested that the Mn, Cu, and Fe contents are significantly high in the dark band region. Combining in situ LA-ICP-MS mapping of trace elements, UV–Vis spectra, and EPR analysis results, it was suggested that Mn, Cu, and Fe are the major contributors to the greyish-purple color. This study provides a reference for the specific experimental methods to determine chromophores and the origin of color in tremolite jades.

Download

Citations (1)


... The Hetian belt is adjacent to the nephrite-bearing Altyn Tagh region to the east (Gao et al., 2019a;Jiang et al, 2020;Liu et al., 2021Liu et al., , 2022Zhang et al., 2022b;Jiang et al, 2023). Further east, in Qinghai Province, there are the Golmud and other deposits (Yu et al., 2016a, b;Gong et al., 2023). There are several deposits in Northeast China: Tieli in Heilongjiang Province (Gao et al., 2019b;Xu et al., 2022;Xu and Bai, 2022), Panshi in Jilin Province , and Xiuyan and Sangpiyu in Liaoning Province Zheng et al., 2019). ...

Reference:

Voimakan deposit of dolomite type nephrite, Middle-vitim mountain country: formation conditions
Color Origin of Greyish-Purple Tremolite Jade from Sanchahe in Qinghai Province, NW China

Minerals