Everything you wanted to know about diamond knives but did not know who to ask SPI Diamond Knives Everything you wanted to know about diamond knives but did not know who to ask. However we do know that the ultimate radius of curvature that can be given to any material is a function of its hardness, the greater the hardness, the smaller the theoretical limit on radius of curvature. And diamond being the hardest material known to man has the potential for being given the very smallest radius of curvature of any material. Therefore the attraction of diamond over all other materials including glass and even sapphire.
Nothing comes close to diamond in hardness.
Putting it another way, the sharper the knife the lower the force needed to amke a cut, and therefore also, the lower the distortion. The attention being paid to the very smallest possible radius of curvature means that an SPI Diamond Knife will cut with the very smallest possible force, resulting in the very lowest amount of specimen distortion. Without this very smallest of radius of curvatures, one could not cut sections we estimate to be down to the 25 nm range. All SPI Supplies diamond knives are given the ultimate quality inspection, that is, they are used to cut a plastic block which is then inspected by TEM to inspect for the presence of striations. Life science diamond knives are given the very highest level of inspection since no striations are tolerated.