The diamond's table (top facet) is the larger window on top of the diamond that allows you to peek inside. It's the most significant facet of a round diamond. The round diamond's depth is the stone's height (in millimeters) measured from the culet (bottom tip) to the table (flat, top surface). The ideal table percentage for round diamonds is generally between 63 and 56 percent, and the perfect depth for round diamonds is typically between 62.9 and 59.5 percent.