Abstract: A device is proposed for the precision rotation of samples on a diffractometer, especially for X-ray or synchrotron radiation diffraction experiments, comprising: a centering element (26) which is held at one end of a motor-driven rotating shaft (22) and can be displaced in a plane orthogonal to the axis of rotation of the rotating shaft (22), a sample holder (30) which is fixed to the centering element (26) or integral with the latter for holding a sample (32) substantially centrally with respect to the axis of rotation in an X-ray or synchrotron radiation beam (S), at least one micrometer finger (36) which is arranged in the region of the centering element (26) and can be positioned orthogonally with respect to the axis of rotation of the rotating shaft (22) by means of a micrometer finger drive device.