CUT Cut has the greatest influence on a diamonds fire and brilliance. A round, brilliant-cut diamond has 58 facets. When well-proportioned, this shape best shows the stones brilliance because it allows the most light to be reflected back to the eye of the observer. Stones that appear lifeless or seem dark in the center are probably poorly cut. When the angle relationship between the crown and pavilion facets is correct, rays of light entering the diamond strike the rear facets at an angle greater than the critical angle (24.5 degrees for a diamond) and reflect back to the eye of the observer. If the stone is cut too deeply, the light strikes the rear facets at an angle less the critical angle and the light is lost through the sides of the diamond. If the stone cut is too shallow, the light passes through the diamond without being reflected back. |
