Bismuth germanate (Bi4Ge3O12; BGO) single crystal has been grown by the Czochralski technique. High resolution X-ray rocking curves and transmission spectra were obtained for samples cut from shoulder, middle and bottom portions of the ampoule. The surface emission and excitation-emission spectrum were taken and the emission was found to have a peak at 480 urn. Energy resolution spectrum has been taken for a polished BGO sample with Cs-137 and Na-22 gamma sources. The reason for the formation of voids in the crystal and reduction of energy resolution is presented. (C) 2002 Elsevier Science B.V. All rights reserved.