There is only one factor that contributes to the twinkle of a gem: diamond cut. This refers to the polish, proportions, and symmetry of a diamond—not the stone's shape. The quality of a diamond ...

High-quality ... Brilliant Cut 6.47×6.47mm, Princess Cut 5.51×5.51mm, Cushion Cut 5.83×5.83mm, Asscher Cut 5.61×5.61mm, Oval Cut 8.12×5.41mm will prove the best. 1 carat diamond rings ...