HOW WOULD YOU PERFORM A HARDNESS TEST ON CERAMIC WITHOUT IT CRACKING? I HAVE TWO CERAMICS THAT I NEED TO COMPARE THE HARDNESS OF. AT PRESENT WE ARE BORING THEM WITH AN I.D. TOLERANCE OF 0.001MM AND FOUND THAT ONE OF THE CERAMICS WILL HOLD SIZE AND SURFACE FINISH BETTER THAN THE OTHER. ANY COMMENTS WOULD BE APPRECIATED