Mohs scale of mineral hardness finding the hardest material that the given material can scratch, or the softest material that can scratch the given material. For example, if some material is scratched by apatite but not by fluorite, its hardness on the Mohs scale would fall between 4 and 5. "Scratching" a material for the purposes of the Mohs scale means creating non-elastic dislocations visible to the naked eye. Frequently, materials that are lower on the Mohs scale can create microscopic, non-elastic dislocations on materials that have a higher Mohs number. While these microscopic dislocations are permanent and sometimes detrimental to the harder material's structural
On the Rocks (play) there is nothing new in this, since the "extermination of what the exterminators call inferior races is as old as history." What is new is that modern politicians since the French revolution have created a social principle of extermination, whether it be of aristocrats as in the case of France, or Jews as in Germany. This is an outgrowth of class conflict, but in the future such decisions can be made scientifically. On the Rocks (play) On the Rocks: A political Comedy (1932) is a play by George Bernard Shaw which deals with the social crisis of the Great Depression.