Gd2Ti2O7 (GTO) single crystals having dimensions of 17 x 17 x 20 mm(3) were grown by the Czochralski method. These crystals displayed a strong growth habit with (1 1 1) facets. The colors of the as-grown crystals were sensitive to the oxygen concentration both during growth and post-growth annealing. The possible reason for the different colors is discussed and based on transmission, energy dispersive Xray spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) analyses. (C) 2014 Elsevier B.V. All rights reserved.