The table percentage demonstrates how much of the cross-sectional area is table and how much is crown angle. The ideal table is 53% and is infrequently encountered. A “trade ideal” of 60% table is frequently seen and acceptable in most fine jewelry circles. The smaller table diamonds are more expensive to produce but are sought after by diamond fanciers because of the larger prism (greater area of crown angle) capable of dividing light into its spectral colors created by the smaller table.
Many students are curious as to how the table is measured since it is an octagon. A microscopic millimeter “ruler” is placed over the table and the measurement taken point to opposite point of the octagon. A method of visual inspection of the two squares that make up the octagon. Visual estimates of table size can be made (with practice) depending upon the degree to which the sides of these squares bow in or bulge out.