Ideal Cut Diamonds: The leading gemological laboratory that assigns a cut grade to round diamonds is the American Gem Society. They use three factors to determine this grade: polish, symmetry, and proportions. The AGS assigns an "Ideal 0" cut grade to those diamonds that have met the "Ideal" criteria for all three factors.

• Polish : The final finish must be perfectly void of any streaks or marks left over in the cutting process.
• Symmetry : Every facet must be of equal size and perfectly positioned opposite of its counterpart on the crown and pavilion of the diamond.
• Proportions : Ideal proportions are those strict angles and proportions that will provide the the perfect balance of brilliance and fire, maximizing the beauty of the diamond.

Why aren't all diamonds cut to AGS "Ideal 0"? The answer is time and money. It takes an experienced cutter years before he is able to cut to this level of perfection. In many cases, cutters do not want to cut these elite diamonds. Being paid by the piece, most diamond cutters would rather mass produce inferior cuts for which there is more demand. It takes a master cutter about twice as long to finish cutting an AGS "Ideal 0" than it does to complete an average diamond. He will use his magnifying loupe many hundreds of times, and will check his work by computer dozens of times. The cutter removes much more of the original rough diamond than he would in cutting the average diamond. This weight loss and the extra time it takes the master cutter to achieve this level of cutting perfection is why AGS "Ideal 0" cut diamonds command the premium prices they do today.