The little side at the bottom idea of a gemstone. The exceptional culet should be pointed or quite tiny (graded "compact" or "none"). The dearth of crystallized carbon is why CZ differs chemically, physically, and optically from an earth mined and lab created diamond. For round diamonds, the measurement http://waylonbmvcl.csublogs.com/3156216/helping-the-others-realize-the-advantages-of-lab-created-diamond