帮人帮到底, 送佛送到西! When you shop for a diamond you would like a beautiful diamond that gets noticed in a crowd and that you can be proud of. What makes a diamond beautiful and gets noticed is the way it plays with light, or the Light Performance. To evaluate a diamond’s beauty, it is typically rocked back and forth in a well-lit room or under a diamond light. Tilting the stone changes the angle that light enters its facets. It’s wise to choose a retailer fully trained and equipped to sell diamonds based on Light Performance standards.