gems, jade, jadeite, fei cui, Myanmar, causes of color, red jade, red jadeite, fei cui, heated jade, heated jadeite, fei cui, goethite, hematite, limonite

In this paper, the color-causing elements and mineral composition of the Fei-color (red color) jadeite jade were analyzed using X-ray fluorescence spectroscopy and X-ray diffraction techniques to systematically study Fei-color jade; during epigenetic oxidation, iron oxide minerals fill and disseminate in gravel fissures and mineral gaps, resulting in Fei-color—which includes yellow and red—and the results show that the concentration of Fei-color is proportional to the iron content, with manganese being the main cause of the sepia tone in Fei-color jade, yellow coloration resulting from limonite, and red hue appearing when limonite partially transforms into hematite due to dehydration, while the upper limit temperature for heat-treated Fei-color jade is about 580 °C.