different benchmarks is given below: Crown height, pavilion depth, and table diameter are percentages of the total girdle diameter. Because the pavilion angle (and consequently pavilion depth) is so closely tied to total internal reflection, it varies the least between the different standards. Hearts and arrows phenomenon The term "hearts and arrows" is used to describe the visual effect achieved in a round brilliant cut diamond with perfect symmetry and angles that exhibit a crisp and complete pattern of hearts and arrows. When viewed under a special magnifying viewer, a complete and precise visual pattern of 8 hearts is seen while looking down through the pavilion, and 8 arrows can be seen when viewing the stone in the table up position. The Passion Cut Another modification of the round Ideal Cut that maintains the basic proportions of its angles is the Passion Cut. This cut's design can be considered the opposite of the Hearts and Arrows, as it eliminates the arrows in order to capture a different light return from the center of the diamond. The cut splits the eight pavilion mains and increases the specifically-placed total facets from 57 to 81. The cut was designed to enhance brilliance and mask inclusions. Fancy cuts Even with modern techniques, the cutting and polishing of a diamond crystal always results in a dramatic loss of weight; rarely is it less than 50%. The round brilliant cut is preferred when the crystal is an octahedron, as often two stones may be cut from one such crystal. Oddly-shaped crystals such as macles are more likely to be cut in a fancy cut (that is, a cut other than the round brilliant), which the particular crystal shape lends itself to. The prevalence and choice of a particular fancy cut is also influenced by fashion; generally speaking, these cuts are not held to the same strict standards as Tolkowsky-derived round brilliants. Most fancy cuts can be grouped into four categories: modified brilliants, step cuts, mixed cuts, and rose cuts. Modified brilliants This is the most populous category of fancy cut, because the standard round brilliant can be effectively modified into a wide range of shapes. Because their facet counts and facet arrangements are the same, modified brilliants also look (in terms of brilliance and fire interplay) the most like round brilliants. Modified brilliants include the marquise (a prolate lemon-shape, also called navette, which is French for