Deep Pavilions (5.19)
Even without the Table Reflection Method, very deep pavilions are easily spotted from a distance. Deep pavilions are noticeably dark due to loss of light and a very large table reflection. They are very common, because of the desire for maximum weight retention in many cutting shops. This is especially the case with lower quality goods, since these stones will not face the degree of scrutiny that finer qualities would.
In re-cutting diamonds, the general rule of thumb with deep pavilions, is to gauge finished weight by the starting diameter of the diamond. The only exceptions to this rule are if inclusion removal comes into play, or if the crown requires steeper angles or a smaller table. If that’s the case, more girdle will likely be necessary, thus reducing the diameter of the stone.
Along with the very small, or absence of, the table reflection, a flat pavilion displays a “fish-eye” (which will be discussed in more detail shortly). This is always considered a very negative characteristic and the stone should be devalued accordingly. Sometimes a diamond with proper pavilion angles, has a large culet that shrinks the pavilion depth below acceptable parameters. This reduces light containment and again has a negative effect on value.