What the GIA Study Overlooked Your January issue deals with “Ideal” proportions of diamonds as researched by the Gemological Institute of America and others (“GIA to Ideal Cutters: Back to the 3-D Drawing Board,” p. 96). But that research has almost totally neglected the most obvious contribution to the beauty of a diamond – symmetry. In fact, that word appears only three times in your five-page report! For instance, each set of opposing bezel facets and corresponding pavilion mains of a round brilliant-cut 58-facet diamond must be perpendicular to an intersecting plane in order to return maximum light to the eye of the viewer. Not once, but eight times around! And most important, if the opposing pavilion facets fail to perfectly “mirror” each other, light is lost and brilliance is diminished. GIA’s computer modeling assumes perfect symmetry and quite correctly shows

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