A diamond has a number of elements to describe the cut and the quality of the diamond. Cut doesn’t refer to a diamond’s shape (e.g. round, oval, pear, etc.) but instead to a diamond’s proportions, symmetry and polish. The beauty of a diamond depends more on cut than any other factor. When light strikes a diamond, approximately 20% immediately reflects off the surface. Of the 80% that enters, a portion will escape through the bottom of the diamond. A well-proportioned diamond will have each facet properly placed and angled so as to maximize the amount of light that reflects back out of the top of the diamond. This reflected light is often referred to as scintillation, fire and brilliance.
The cut grade wasn’t a standard measurement in the industry until only recently, and even that standard is generally only applied to round diamonds. Cut grades can be: Excellent, Very Good, Good, Fair, and Poor.