Abstract: Two types of "Mo Yu" samples with similar appearance but different gemmological characteristics were collected from Nanyang jade market, and the samples are reportedly deposited from Guangxi Province and other southwest regions in China. Through conventional gemmological tests, as well as other tests using Infrared spectrometer, X-ray fluorescence spectrometer, X-ray powder diffractometer, Raman spectrometer etc. It is found that both types of samples are mainly composed of tremolite, one type of which contains graphite minerals, and the samples' textures are relatively fine. One of the reasons for the black appearance is natural formation, and the base colour is white or grayish white when the samples are viewed under microscope, as tiny graphite minerals can be seen scattering in the samples. According to the national standards, it should be named Nephrite or Hetian Jade, and belongs to the category of Mo Yu. The other type is caused by artificial treatment, and the specific method is unknown. Although by naked eye, the treated samples also have black appearance, but when magnified, it shows brown base colour. The fluorescence phenomenon of treated samples is weak, and the peak of tremolite cannot be observed in Raman spectrum. Different from the natural samples, it can be named nephrite (treated) or Hetian Jade (treated) according to the national standards, but can not be named as Mo Yu.