Light entering the diamond reflects internally from facet to facet and is reflected back through the top only, creating maximum brilliance, scintillation and dispersion. The arrows on the diagrams indicate the flow of light in the diamond.
Most diamonds are “spread” in their cutting to retain maximum weight from the original rough. A heavier diamond will result, but with the sacrifice of fire and brilliance.
When a diamond is cut too deep, light* leaks out of the bottom, brilliance is lost, and the center of the diamond will appear to be dark. This is called “Nailhead.”
When a diamond is cut too shallow, light* leaks out of the bottom, brilliance is lost, and the diamond appears watery, glassy and dark. This is called “Fisheye”.
The quality factors of Cut, Color, and Clarity can dramatically affect the beauty and value of a diamond. Because of cutting, diamonds with the same color and clarity grades can vary in value by as much as 50% or more. Therefore, it is advisable to consult a credentialed gemologist before purchasing any diamond.
The cut or proportions of a diamond dramatically affects both how much the diamond weighs and how well it reflects light. When a round brilliant diamond has been cut to “Ideal” proportions by a master cutter, it is a splendor to behold.
The Ideal Cut Diamond describes a round brilliant diamond that has been cut to exact and mathematically proven proportions. Its symmetry, with 58 exactly placed facets, produces the ultimate in luster and beauty.
When a diamond is cut to ideal proportion, all of the light entering from any direction is totally reflected through the top and is dispersed into a display of sparkling flashes and rainbow colors.
Diamonds are sold by weight in carats. The heavier the diamond, the more valuable it is. But bigger doesn’t necessarily mean better. Quality is found in diamonds of all sizes.
The carat weight sacrificed for the purpose of good to ideal proportions also factors into the price. In the illustration to the right, the shaded portion represents wasted crystal. All three are one carat diamonds; however, the two on the right are poorly proportioned and thus much less expensive.
Most diamonds, although appearing colorless, actually have a slight tone of yellow or brown. As these tones become more apparent, the rarity and cost decrease. A diamonds color grade is defined by a letter ranging from "D - Z" -- "D" being colorless and "Z" being fancy yellow.
Practically all diamonds contain naturally occurring internal characteristics called inclusions. The size, nature, location and amount of inclusions determine a diamond’s clarity grade and thus its cost. One unique advantage of the Ideal Cut is that its sparkle can mask otherwise noticeable inclusions.