What is a diamond’s “cut”?

The term diamond cut has two meanings in relation to diamonds. The first one is used to label a shape, such as the “Cushion Cut”, “Emerald Cut”, and “Princess Cut.” The second one relates to the quality of the cut within the shape and not the shape itself. This includes the symmetry, polish, and proportion created to shape a diamond. It is also this sense of the word cut that is graded and scored on diamond certificates and is considered by gemologists as one of the most important determinants of a diamond’s value. So when you look to purchase diamonds, be sure to pay attention to its cut.

What does an uncut diamond look like?

A raw, uncut diamond can almost be mistaken for a plain-looking, unpolished quartz crystal--or even lumps of washing soda or coarse salt. What brings out a stone's beauty and sparkle is its cut. Ideally, a "good cut" gives a diamond brightness and “fire” that reflect from the very core of the diamond.

 

What makes a well cut diamond?

When designing a cut for a diamond, it is important to consider three factors. The first one is the diamond’s brilliance, or the amount of light that's reflected back to the viewer. The second is its "fire," which refers to the flashes of spectral colors you see when viewing a diamond from different angles. And lastly, there is scintillation, which refers to the pattern of light and dark areas and the sparkle that is generated when a diamond is moved.

What about cutting fancy colored diamonds?

While brilliance, fire, and scintillation are of supreme importance when cutting white diamonds, they are only of secondary importance for grading colored diamonds. The goal of cutting white diamonds is to get them to be as colorless as possible. Obviously, for colored diamonds, we want to do everything we can to bring out the intensity of the color.

Therefore the goal of any good cutter is to make a colored diamond's color stand out. There are many ways they do this. Often, cutters create more elongated asymmetric facets on fancy colored diamonds to help restrict the light and retain much of its color. Many cutters also use lesser facets to capture the color inside. This runs against the traditional way of faceting a white diamond.

Certain shapes also make the color of a diamond more intense. Cutters often cut fancy colored diamonds to Radiant, Cushion, Oval and Pear shapes since they concentrate more color in the stone. On the other hand, shapes such as Round and Emerald cuts are rarely used because the stone’s natural color tends to lose its intensity after it's shaped and faceted by the cutter.