Lower Girdle Facet Height (5.38)
The height of the lower girdle facets on the pavilion are especially critical. This is one quick way to identify an older cut from a modern round brilliant. The general rule is: The shorter the Lower Girdle Facets and the larger the culet, the older the cut . By not extending the Lower Girdle Facets to at least 75% and sometimes up to 88% (3/4 to 7/8), the center of the diamond is left lacking in brilliance. It’s like the picture frame that only goes part of the way around the painting. Some cutters use the rule of thumb that the smaller the table, the longer the Lower Girdle Facets, and the larger the table, the shorter the Lower Girdle Facets. This provides visual appeal as a more pleasing ratio in comparing the bottom kite-shape images to the size of the table, when looking through the table of the diamond. Many would say this is pure nonsense, but a cutter that gets into the nuances of 10x esthetics would strongly stand by this style.
