Abstract: A method generating a more accurate 3D model for at least two gemstones using external surface of the gemstones; storing, in memory, the more accurate 3D model of the first gemstone and the second gemstone; comparing the more accurate 3D model of the first gemstone and the more accurate 3D model of the second gemstone from the stored memory; calculating, based on the comparison, a matching score for the more accurate 3D model of the first gemstone and the more accurate 3D model of the second gemstone, the matching score being informative of a match between the first gemstone and the second gemstone; and identifying the first gemstone and the second gemstone as being the same gemstone when the matching score meets a predefined matching criterion.

Abstract: The invention relates to a device for dressing a grinding wheel, comprising a sleeve to hold a corundum rod laterally and to guide it along its longitudinal axis, a ram to apply constant thrust force onto the corundum rod held in place and guided in the sleeve, to bring it into contact with the grinding wheel, means of rigidly connecting the ram shaft to the end of the corundum rod, and linear guide means for the sleeve for translating the corundum rod parallel to the axis of the grinding wheel while keeping the rod pressed against the grinding wheel with a constant force. Application to a centerless grinder in which the grinding wheel is used to grind nuclear fuel pellets.