MINERALOGY AND GEMMOLOGY OF SHOUSHAN STONE

Shoushan Stone is a famous gemstone in Fujian and has more than 100 varieties. Over 50 samples of Shoushan Stone have been studied using XRD and IR. Shoushan Stone can be divided into three groups based upon the density. The first group has density of 2.57~2.67 g/cm³, consisting mainly of dickite; The second has density of 2. 71~2. 79 g/cm³, containing illite; The third has density of 2.81~2.87 g/cm³, with pyrophyllite as its major mineral. Therefore, it is possible to determine their mineral constituent on basis of their densities. There are differences in the mineral constituent between the varieties of Shoushan Stone. Gaoshan Stone, Duchengkeng Stone and Kengtou Stone are composed of dickite, Yuewei Stone and Furong Stone consist of pyrophyllite. Shanbodong and Qijiang Stones contain kaolinite. Tianhuang Stone, the best variety among Shoushan Stone, is complex in their mineral constituent, and dickite, nacrite or illite have been found as the major mineral. Most of samples of Tianhuang Stone have ilite as a minor mineral, which seems to be an important feature of Tianhuang Stone and is probably related to hydration during its formation.