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Copyright of Journal of Guilin University of Technology is the property of Journal of Guilin University of Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Guilin University of Technology is the property of Journal of Guilin University of Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Guilin University of Technology is the property of Journal of Guilin University of Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Guilin University of Technology is the property of Journal of Guilin University of Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: Color is the important manifestation of nephrite value. Qinghai nephrite has different colors, but there is a lack of research on coloration. In recent years, the study on the coloration of nephrite in Qinghai mainly focused on azure-green and blue-violet, and it was considered that Cr3+ and Mn2+ were respective coloration elements of azure-green and blue-violet. The color of Qinghai nephrite is not a simple color, such as white-green, azure-green, and blue-violet. Therefore, Qinghai nephrite should contain a variety of color-causing elements. OBJECTIVES:To reveal the color-causing elements of eight colors of nephrite from Qinghai based on the relationship between analysis data and hue changes. METHODS: X-ray Fluorescence Spectrometry (XRF), Chemical Titration, Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and Electron Paramagnetic Resonance Spectroscopy (EPR) were used to study the color-causing elements of nephrite. RESULTS: The color-causing element of white Qinghai nephrite was Fe3+. The color-causing elements of white-green and azure-green Qinghai nephrite were Fe2+ and Fe3+, respectively. The chromogenic elements of green Qinghai nephrite were Fe2+, Fe3+ and Mn in high valence. The color-causing elements of azure-green Qinghai nephrite were Fe2+, Fe3+ and Cr3+. The chromogenic elements of yellow and brown Qinghai nephrite were Fe3+ and high-valence Mn. Fe3+ and Ti4+ were the color-causing elements of blue-purple Qinghai nephrite. CONCLUSIONS: This study determined the color-causing elements of different colors of Qinghai nephrite, which provided a theoretical basis for the study of the coloration mechanism of Qinghai nephrite. [ABSTRACT FROM AUTHOR]

BACKGROUND: Qinghai nephrites show different colors. In recent years, there have been a lot of studies on Qinghai nephrite mineralogy, but the studies on the mineral characteristics of Qinghai nephrite with different colors are lacking. OBJECTIVES: To study the relationship) between color and mineralogical features of Qinghai nepjhrites. METHODS: Polarizing Microscopy, Scanning Electron Microscopy, Electron Probe Microanslyzer and X-ray Powder Diffraction were used to analyze the microtopography, microstructure, mineral composition and crystallinity of tremolite. RESULTS; Tremolite in white, blue-violet and brown Qinghai nephrite are mainly fibrous and have micro-fiber blastic texture with crystallinity of 96. 12% -96. 88%. Tremolite in green-white and viridis Qinghai nephrite are mainly foliated, and has micro-foliated blastic texture with crystallinity of 97.32% and 97. 35% , respectively. Tremolite in green and azure-green Qinghai nephrite are mainly foliated, and have microscopic blade -cryptocrystalline blastic texture with crystallinity of 95. 29% and 95. 48% , respectively. Tremolite in yellow' Qinghai nephrite is mainly columnar, and has micro-columnar blastic texture and crystallinity of 97. 84%. The main mineral different color Qinghai nephrite is tremolite, with content of more than 95%. Some minor minerals only appear in the specific color Qinghai nephrite, such as titanite in viridis Qinghai nephrite, anorthite in yellow Qinghai nephrite, magnesite in green Qinghai nephrite, chromite in azure-green Qinghai nephrite, and clinozoisite in brown Qinghai nephrite. CONCLUSIONS: There are differences in mineral features of Qinghai nephrite in different colors, which provide scientific basis for the study of ore-forming environments and conditions of Qinghai nephrites in different colors. [ABSTRACT FROM AUTHOR]