Nephrite is used to be considered as aphanitic mineral aggregate which belongs to Fe-poor and Mg-rich member of actinolite-tremolite series. Usually, the mineral names (tremolite and actinolite) are distinguished on the basis of Mg/(Mg+Fe2+) ratio( 0.9 to be considered as the boundary). 17 samples of Hetian jade, Manasi green jade and Xiuyan old jade which come from Xinjiang, Liaoning and Qinghai have been investigated by means of XRD. The results show that all the samples are almost totally composed of tremolite, very few impurity can be found. No distinct relationship between peak positions and FeO contents can be determined. The diffusion of the peak shape probably indicates the variaton of crystallinity and grain size of the mineral composition.