Study on Gemmology of Non-Pyrophyllite-Type Qingtian Stone from Zhejiang Province

It is a controversial problem that the type assignment of the Qingtian Stone from Zhejiang Province belongs to the pyrophyllite-type or not.In order to solve this problem，some measurements such as X-ray powder diffraction analysis，infrared absorption spectrum ，scan electron microscope and differential thermal analysis are adopted.The results show that the main species of Qingtian Stone are pyrophyllite-type，but there also exist some species which are not pyrophyllite-type，such as dickite-type，illite-type，sericite-type and so on.In this paper，the gem features and mechanism of the Qingtian Stone are discussed．