Hard x-ray beams with non-zero angular momentum are generated by diffraction on a specially designed spiral-like zone plate. In the talk the simulations of the wavefield behind the zone plate will be presented based on a rigorous evaluation of the exact Huygens-Fresnel diffraction integral beyond the paraxial approximation. Unlike conventional vortex light in visible or IR range, vortex x-rays diffract in a crystal lattice showing peculiar diffraction effects demonstrated both theoretically and experimentally. Possible effect of an x-ray vortex beam on static poling of ferroelectric GeTe will be discussed.