Among precious stones, diamond has the highest luster-diamond luster, with high refractive index (2.4 17) and high dispersion (0.044), which determines that diamond can shine brilliantly. The cutting process is to better reflect the characteristics of the diamond itself. In addition, only direct light (sunlight, light) can fully show the dazzling fire color of diamonds. Diamonds are bright white in white and gray light. So lights, especially spotlights, will make diamonds shine brilliantly.