The cut is one of the 4Cs of diamonds. The cut grade is determined by how well-proportioned the surfaces, or facets, of the diamond are.
Why is cut important?
The cut of the diamond directly affects how light enters and reflects back out of the diamond. An Ideal cut diamond will provide superior brilliance, while a diamond that is too shallow or too deep will allow more light to exit the stone before being reflected back out, giving the viewer less sparkle.
How many cut grades are there?
Technically, there are five cut grades, including Poor/Fair, Good, Very Good, Ideal, and Astor by Blue Nile™. However, you'll never find a Poor/Fair cut grade diamond sold at Blue Nile.
How is light performance tested?
Light reflection varies greatly from one stone to another. For this reason, every diamond we carry is tested for light performance by the GemEx BrillianceScope® Analyzer with spectrophotometer technology.