Abstract: A new kind of green jade was found recently in Kuandian，Liaoning Province.In order to find out the gemmological characteristics and colour causes of the green jade，this paper investigates the gemmological characteristics，mineralogical characteristics，spectrographic characteristics，chemical compositions and trace elements of the sample by using the conventional gemmological identification methods，polarizing microscope，infrared spectrometer （FTIR），laser Raman microspectrometer，X－ray powder diffraction spectrometer（XRD），X－ray fluorescence spectrometer（XRF）and fiber optic spectrometer.The results show that the main mineral component of the sample is muscovite，with minor auxiliary mineral of rutile.The cause of its green colour is the isomorphic replacement of Cr^3＋to Al ^3＋.According to the national standard，the sample is named as muscovite jade.