Diamonds are unique among gemstones in their ability to transmit light, giving them an intense sparkle. The cut grade is about how well a diamond’s facets interact with light. Cut is crucial to the stone’s overall beauty and value, and is the most complex of the 4C’s therefore, the most difficult to technically grade.
To determine the cut grade of any diamond, GIA calculates the proportions of those facets that influence the diamond’s face-up appearance. These proportions allow us to evaluate how successfully a diamond interacts with light to create the desirable effects such as brightness and fire.
Cut grade also takes into account the design and craftsmanship of the diamond. This includes weight relative to its diameter, girdle thickness, the symmetry of its facet and the polish quality on the facets.
The GIA Cut Scale is standard for all diamonds. contains 5 grades ranging from Excellent, Very Good, Good, Fair & Poor.