When a diamond is cut, its facets are arranged in a manner that reflects light. The way a diamond is cut and polished determines the amount of light it reflects.A diamond that is brilliantly cut reflects more light and is brighter as compared to a poorly cut diamond. You can grade a diamond in terms of its cut, from Excellent(EX) to Fair(F). Be it mined diamonds or lab grown diamond jewelry in San Diego, CA, you can assess the brilliance of your diamond jewelry by observing the cut of the diamonds.