BGSO polycrystalline powder was synthesized as starting material by sintering of 4 N Ge2O3, SiO2 and Bi2O3 using solid state reaction method. Using < 0 1 0 >-oriented Bi4Si3O12 crystals as seeds, the mixed crystals of (Bi-4(GexSi1-x)(3)O-12, x=0.05, 0.1, 0.15, BGSO) have been grown by the vertical Bridgman method. Transparent BGSO crystals with a size up to 10 x 15 x 30 mm(3) have been obtained. The lattice parameters increase monotonically with increasing Ge3+ content. The transmittance spectra of BGSO single crystals were achieved in the UV and visible light regions and the absorption edge of BGSO crystal is about 285 nm. (C) 2012 Elsevier B.V. All rights reserved.