For Brilliance, Not Carat Weight
The beauty of a diamond depends on how well it has been cut more than anything else. Understanding the cut of a diamond begins with the stone's shape. However cut as a value factor that determines the beauty of a stone refers to a stone's proportion, symmetry and polish. Although nature determines a rough diamond's clarity, carat weight and color, the hands of master craftsmen release its fire, brilliance and scintillation. When a diamond is cut to exacting proportions - neither too deep nor too shallow - light will reflect inside the stone from one mirror - like facet to another and reappear through the top of the stone, making it seem to radiate from within.
Only D, E, and F
Diamonds are transparent, most display barely perceptible hints of color. The less color in a diamond, the rarer it is.
Diamonds are graded on a color scale from D through Z, based on their degree of colorlessness.
Fancy colored diamonds are an exception and are also much sought after due to their extreme rarity - particularly yellows, pinks and blues. Their quality is judged by the intensity of their hue, and unlike white diamonds, the more color, the rarer.
Clean to the Naked Eye
Virtually all diamonds contain identifying characteristics, most of them too small to be seen with the unaided eye. These "inclusions" are nature's birthmarks; when viewed using magnification they look like tiny crystals, clouds or feathers.
To determine a diamond's clarity grade, a gemologist will consider the size, number, position, color and general nature of any inclusions.
Diamonds exhibiting no such inclusions are categorized as flawless (FL) or internally flawless (IF). In general, the greater the number and size of inclusions within a diamond, the lower its clarity grade. Heart of Gold diamonds are selected from the top clarity grades; any inclusions only become visible under 10x power magnification.
Not all Diamonds are Equal
A diamond's size is measured in carat weight. Carat weight is commonly expressed in points. Each carat equals 100 points or 1/5 of a gram.
Larger diamonds are valued because they are found less frequently in nature. But diamonds of equal carat weight may vary greatly in brilliance depending on their proportion and cut. Therefore, carat weight alone is a poor guide for value. It is the complex combination of cut, color, clarity and carat weight that determines a diamond's quality and brilliance.