Geologic Features of Placer Oriental Sapphire Deposits in Eastern Coastal China

As one of the important and precious non-metallic minerals, placer oriental sapphire within basalt of Cenozoic in the eastern coastal China is disscused on its mineralization, geology of deposits and its relationship with geotectonics, in order to provide some messages of exploration. Distribution and the chemical composition of basalt are studied, morever, some potential mineral belts are put out. Occunence, mineral assemblage and principles of mineralization are discussed, similarities and differences in different regions are pointed out. Oriental sapphire, acorite in Hainan and Fujian and ciannamon garnet are analysed. It is revealed by the author that the forming of placer oriental sapphire is controlled by tectonic-magma and weathering. It worth to pay attention to the aluminium hupersaturated basalt, especially for the developed region of washed and drifted deposits.