Why is an oblong diamond called an “emerald cut?”
Don’t worry—your diamond isn’t turning green with envy. In this case, “emerald” refers to one of the classic styles of diamond cut.
While the different styles of diamond commonly are called “cuts,” names like emerald, princess, pear, and marquise, oval, or round actually refer to the shape of a diamond, while the word cut technically refers to the arrangement of facets within the diamond to maximize light return. The way the individual facets are cut—their angles and proportions in relation to each other—is what gives a diamond its magnificent sparkle. That said, however, each of the traditional shapes also has a basic arrangement of facets, so using the word cut really is just fine.
An emerald-cut diamond got its name because it mimics the way emeralds are traditionally cut. Emeralds belong to the beryl family of minerals, while diamonds are pure carbon. The crystalline structure of a beryl grows in a vertical pattern, which lends itself best to the familiar oblong we often see in emeralds, especially for larger stones.
Because an emerald-cut diamond has such a large table (the top of the stone) in proportion to the rest of the stone, inclusions are especially noticeable with this cut. Equally noticeable is an off-color stone. For this reason, emerald-cut diamonds tend to be exceptionally high color and clarity, and therefore typically are more expensive than other cuts of the same weight.
Because of its facet arrangement, an emerald-cut diamond may not have the same degree of fire as other cuts. A brilliant cut, such as the popular round, has kite-like facets radiating from the center. A step-cut like the emerald has elongated parallel facets, and a mixed cut employs both types of facets.
At left, a face-up drawing of an emerald-cut diamond shows the large table and step-cut facet arrangement. At right, the stone is flipped over for a view of the facets underneath.
Think of an emerald cut diamond as a crystal clear pool of water reflecting sunlight, whereas a round brilliant is more like a twinkling star or a camera’s flash. For those who want the best of both worlds, diamond cutters have developed a newer version of the emerald cut, called a radiant cut, which is a mixed cut combining the shape of an emerald cut with the addition of some brilliant kite-like facets to reflect more light. While a radiant is a beautiful option, the elegance and quality of a classic, understated emerald cut remains unparalleled.