Abstract:There are numerous granitic pegmatites with rare- metal mineralization in the Shangnan- Danfeng area of East Qinling. We report the presence of fergusonite and yttrium niobate in Rb- rich granitic pegmatites in this area for the first time. This mineral mainly occurs as a late- stage phase in garnet- rich microcline granitic pegmatites and is commonly associated with garnet, zircon, xenotime, columbite, and other accessory minerals. Electron probe micro- analysis (EPMA) shows that in addition to major elements including Y, Nb, REE, Ta and Ti, the fergusonite also contains high contents of radioactive elements: UO2 (>5%) and ThO2 (>1%). The contents of elements including Pb, Ca and Si are all<1%, suggesting that these elements are minor or trace elements. The analyzed fergusonite belongs to the fergusonite- formanite series whose Nb/(Nb+Ta) value is close to 1. The fergusonite shows strongly enrichment in heavy rare elements (HREE). Due to the high contents of U and Th in fergusonite, the fergusonite may occur in metamict form. This paper attempts to use Laser Raman to analyze the crystal structure of fergusonite and explore the effect of high contents of radioactive elements of fergusonite on its crystal structure.