Summary: Vincentite, a new palladium mineral containing As, Sb, and Te, has been discovered in platinum-gold concentrates from the Riam Kanan River, SE. Borneo. It occurs as small grains (up to 40 µm) in iron-bearing platinum. In reflected light, vincentite is light brownish-grey and in some sections weakly anisotropic. Reflectance at 470, 546, 589, and 650 nm is 46·3–47·5, 49·2–52·8, 51·7–53·9, and 54·9–56·0, respectively. VHN15 = 494. Electron probe analysis has been performed on two grains, the compositions of which are (Pd5·32Pt0·68) (As0·90Sb0·48Te0·65) and (Pd5·17Pt0·83) (As0·89Sb0·70Te0·45) or, simplified, (Pd,Pt)3(As,Sb,Te). This is distinctly different from both arsenopalladinite, Pd5(As,Sb)2 with As > Sb as defined by Clark (1974), and mertieite, Pd5(Sb,As)2.
The following lines have been observed in the powder pattern: 4·180, 3·950, 3·240, 2·750, 1·997, 1·749, 0·944. This cannot be matched by the patterns of arsenopalladinite, mertieite, isomertieite, stibiopalladinite, atheneïte, or synthetic Pd3As.
The name is in honour of Prof. E. A. Vincent, of Oxford.