Lattice parameters and crystal composition of langasite grown by the Czochralski method have been characterized in detail by X-ray diffraction (XRD) analysis. The crystal length-frequency coefficient dependence has been obtained. The frequency and elastic coefficients of langasite have been shown for the first time to be determined by the blocks disorientation in the crystal. The polarity reversal observed along the crystal was proved to be due to the stresses originating from the melt composition changes during crystal growth. (C) 2007 Elsevier B.V. All rights reserved.