Abstract: A method of bruting two precious or semi-precious stones which includes mounting the stones on respective first and second rotating shafts whose axes lie in substantially parallel planes but which intersect in the region of the stones when viewed in projection perpendicular to said planes, the girdle surfaces of the stones making grinding contact, one of the shafts being substantially translated relative to the other in its plane such that the reference point of its stone travels along a path in the plane which reaches substantially all points within a parallelogram defined by pairs of lines parallel to the respective shafts, the length of the respective sides of the parallelogram being equal to the height of the girdles of the respective stones and the center of the parallelogram lying over the reference point of the other stone when viewed in such projection.