In order to solve the problem of type assignment of the Qingtian stone from Zhejiang Province, the author made some experiments with such means as X-ray powder diffraction analysis, infrared absorption spectral analysis, scanning electron microscopy and differential thermal analysis. The results show that the main species of Qingtian stone is of pyrophyllite type; nevertheless, there also exist some other types, such as dickite_type, illite-type and sericite-type. This paper has discussed mineral composition, gem features and formation mechanism of the Qingtian stone.