The undoped rubidium gadolinium bis(tungstate) crystals, RbGd(WO4)(2) (RGW), have been grown by the spontaneous nucleation from high-temperature solutions. The crystal structure has been refined at room temperature by using single-crystal X-ray diffraction data. The unit-cell parameters are a = 10.6953(12) angstrom, b = 10.5017(11) angstrom, c = 7.6064(11) angstrom, beta = 130.504(7)degrees, with Z = 4 in space group C2/c, which is a little difference with KGd(WO4)(2). Crystal habits were predicted by the attachment energy model of Hartman and Perdok and we compared predictions to experimentally grown crystal shapes. (c) 2005 Elsevier B.V. All rights reserved.