Abstract <p>The floatation separation of diamond powders, where some grains of synthetic diamond grinding powder were carried to the surface layer (“foam” product) with air bubbles, and the others diamond grains remained in the chamber of the floatation machine to be better wetted with water (“chamber” product), has been studied. It has been shown that the “foam” product diamonds, in contrast to the original and “chamber” powders, have a higher strength of grains and are more homogeneous in strength at the lowest mass content of impurities and minimum specific magnetic susceptibility. To increase the wear resistance of a diamond wheel, the most efficient is to use just the “foam” product and, notably, such efficiency grows with an increase in the machining rate. It has been revealed that the application of a tool with diamond powders after floatation separation (“foam” and “chamber” products) makes it possible to attain a lower value for the roughness parameter <i>R</i>_a as compared to the tools with original diamond powders. At the same time, the fullness of the ground rough surface according to such a bearing surface profile parameter as <i>t</i>₅₀ indicates that this parameter for different variants of applying the tools with diamond powders after floatation sorting is higher than for the tools with powders in the initial state.</p>