A method is disclosed for marking and visualizing an implant by use of an x-ray phase-contrast tomography examination. Further, an implant is also disclosed. In at least one embodiment, implants are used with specific characteristics which are as unambiguous as possible with regard to the phase shift generated by the implants in a phase-contrast tomography examination. In at least one embodiment, these specific characteristics can include the typical self-generated specific phase shift, typical differences in the specific phase-shift values, or typical spatial structures of materials with well-defined phase-shift values.