The Emerald-Cut Diamond is a very popular style known for its beauty and precision. While it lacks the brilliance of diamonds cut with triangular and kite-shaped facets, it more than makes up for it in extreme clarity. It is like looking into glacier-pure ice. The Emerald-Cut diamond is so named because this cut was, originally, used only on emeralds. It is called a step-cut, which is the cut most commonly used on square or rectangular diamonds.