Acta Petrologica et Mineralogica

Henan Miyu jade is an important variety of jade in China, which belongs to the phanerocrystalline quartzite. A systematic geological study of the Miyu jade deposit in Xinmi City, Henan Province, has been carried out, but its gemmological characteristics and color genesis remain controversial. This paper synthesizes the research results of the previous researchers, and obtains the gemological characteristics, spectroscopic research characteristics and chemical composition characteristics of the green series of Henan Miyu jade samples by routine gemological testing, FTIR spectroscopy, UV-VIs spectroscopy, Raman testing and electron microprobe testing. The results show that Miyu jade is a quartzite with good crystallinity. The main mineral component is α-quartz, and minor minerals include muscovite, hematite, carbonaceous minerals, rutile, tourmaline, etc. It has a granular metamorphic structure and a microscopic fine-grained metamorphic structure. Significant characteristic absorption peaks of Cr³⁺ were seen in the UV-visible spectrum. The green color of Miyu jade is related to chromium-containing white mica, and the green color of chromium-containing white mica is caused by the trace elements it contains, such as Cr, V, Ni and other color-causing elements. The darker the green color, the higher the content of Cr, Ni and V. With the increase of Fe³⁺ content, the yellow tone of the sample is more obvious.

green Miyu jade; quartzartzite jade; gemological characteristics; color genesis; Henan