Cut grade is the most important factor in determining the overall appearance of a diamond, because a poorly cut diamond will seem dull even with excellent clarity and color. Conversely, a well cut diamond can have a slightly lower color (G-H) or clarity (SI1-SI2) and still look quite beautiful, due to its superior ability to create sparkle and brilliance.
For superior brilliance, choose a diamond with a Cut grade of Very Good or Excellent for round diamonds, and Good or better in fancy shape diamonds. When choosing a diamond in this range, make sure its Symmetry and Polish are Very Good or Excellent, so that the impact of the above average Cut is not obscured.
For those on a budget, primarily concerned with size, a diamond of Fair - Good cut may be an acceptable choice, especially in fancy shapes. While the diamond will lack the scintillation and brilliance of a well cut diamond, it will allow a significant increase in size for the same price.
Avoid Poor cut diamonds, even if size is the primary concern. Most find these diamonds to be an unacceptable trade off, despite the lower price. Espeka does not offer Poor cut diamonds.