Articles / What You Need to Know About The 'Ideal' Cut

Difference Between Cut and Shape

Ideal cutting is not to be confused with the shape of a diamond. "Cut" refers to the arrangement of a diamond's facets. A diamond that's "ideal cut" is one that has been cut according to a mathematical formula that many experts believe results in the best possible reflection and refraction of light.

Cut Is the Most Important 'C'

Many experts feel that of the famous "Four Cs" (cut, color, clarity and carat-weight), cut is the most critical. Indeed, two diamonds of the same color, carat and clarity can differ in price by as much as 50% due to the quality of the cut. Only a small percentage of diamonds on the market today are ideal cut, however. This is because more of the original rough diamond must be sacrificed to achieve an ideal cut. Traditionally, diamonds are cut so as to retain the maximum carat weight, but sometimes at the expense of the sparkle. Ideal cutting takes the opposite approach.

Why Ideal Stones Are Brilliant In general, an ideal-cut diamond produces maximum sparkle because any light rays that hit it will bend toward the exact center of the stone, and then will reflect through the top of the stone instead of leaking out of the sides and bottom. The American Gem Society recognizes an ideal grade based on a set of proportions established 80 years ago to provide the optimum combination of brilliance and dispersion of light ("fire"). There is some debate in the industry on the exact mathematical formula that is best. An ideal cut is not always going to be your best option when purchasing a diamond, but it's a subject worth discussing with us.

David WeissDavid Weiss

Graduate Gemologist, GIA
Certified Appraiser