Abstract:Phurcalite found in the Zhutongjian deposit of the Xiazhuang uranium ore field in northern Guangdong Province is associated with microcrystal quartz and meta-autunite in space. The mineral occurs as fibrous, fascicular and radiating aggregates and is bright yellow and transparent with vitreous luster. Its streaks are light yellow in color. The Mohs' hardness is about 3. Phurcalite has a perfect cleavage on {010}, good cleavages on {100} and {001}, and greasy luster conchoidal fracture. Under plainlight, phurcalite is light yellow, and it assumes high order bright interference color under crossed nicols. Phurcalite is a symmetrical extinction, biaxial negative, and positive elongation mineral. The chemical composition of phurcalite (EPMA, average of 15 points) is UO3 68.64%, P2O5 11.70%, CaO 9.21% and impurity 0.28%, with H2O 9.25%, totaling 99.26%. According to the data O=16, the empirical formula should be (Ca2.02, K0.05, Mg0.01)2.08(UO2, TiO2, PbO)2.97O1.97(PO4)2.03· 6.32 H2O. On the basis of the analyses of XRD, the system of phurcalite is orthorhombic, the space group is Pbca, and the unit cell parameters are a=1.742 3(5) nm, b=1.603 2(4) nm,c=1.359 9(2) nm; α=β=γ=90°, and V=3.798 64 nm3. Furthermore, the maxima (in cm-1) of the obtained infrared-absorption spectrum were observed: 3 427.10, 1 622.05,1 062.62, 973.26 and 890.91. These features are very similar to those of the known phurcalite.