Diamonds are renowned for their ability to transmit light and sparkle so intensely. We often think of a diamond’s cut as shape (round, heart, oval, marquise, pear), but what diamond cut actually does mean how well a diamond’s facets interact with light. Precise artistry and workmanship are required to fashion a stone so its proportions, symmetry and polish deliver the magnificent return of light only possible in a diamond.

Achieving the best cut for a diamond reflects in the stone’s final beauty and value. And of all the diamond 4Cs, it is the most complex and technically difficult to analyze. To determine the cut grade of the standard round brilliant diamond – the shape that dominates the majority of diamond jewelry – GIA calculates the proportions of those facets that influence the diamond’s face-up appearance. These proportions allow GIA to evaluate what the best cut for a diamond is, by studying how successfully a diamond interacts with light to create desirable visual effects, such as:

  • Brightness: Internal and external white light reflected from a diamond
  • Fire: The scattering of white light into all the colors of the rainbow
  • Scintillation: The amount of sparkle a diamond produces, and the pattern of light and dark areas caused by reflections within the diamond

GIA’s diamond cut grade also takes into account the design and craftsmanship of the diamond, including its weight relative to its diameter, its girdle thickness (which affects its durability), the symmetry of its facet arrangement, and the quality of polish on those facets.

How does pavilion depth affect a diamond’s cut?

The distance from the bottom of the girdle to the culet is the pavilion depth. A pavilion depth that’s too shallow or too deep will allow light to escape from the side of the stone or leak out of the bottom. A well-cut diamond will direct more light through the crown.

The GIA Diamond Cut Scale for standard round brilliant diamonds in the D-to-Z diamond color range contains 5 grades ranging from Excellent to Poor and is the definitive scale for classifying diamond cuts.

Marlene L.
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Stephanie S.
David was extremely kind and knowledgeable. I went in because the diamond on my ring was loose and I was scared to continue wearing it but he had it fixed right on the spot. He also has some... beautiful and unique jewelry pieces! Definitely recommend himread more
e D.
Five stars is not enough for David Stern. He is an amazing artist who designs and creates the most unique and fabulous jewelry. If you have a stone(s), he will create a work of art for you,... suggesting and enhancing your idea, He also has access to the highest quality stones from all over the world . He has been in the jewelry business for years and really knows the ins and outs. If you have jewelry to sell, he will give you a fair price after explaining how he calculated it considering the style, the weight and the quality of the stone(s) He is extremely personable and very pleasant to work with. I am very confident in saying he would never take advantage of you..read more