The easiest mistake to make when purchasing a diamond is to not account for the quality of the cut. Why is this? Whenever people discuss the traits of a diamond, they mention the Four C’s: Color, Clarity, Cut, and Carat. The “Cut,” however, mostly refers to the shape of the diamond, such as pear, princess, or round.
The diamond prices world-wide are based on the Rappaport report, which uses the Four C’s to determine the price. Though the Rappaport report uses the diamond cut to value the stone, it only directly refers to the shape of the stone, and not the cut quality. It is therefore easy to overlook the actual quality of the cut.
How does the cut quality affect the diamond’s appearance? The major thing affected is how the light is reflected out of the stone. A perfectly cut stone will reflect almost all light that goes into the stone, back to your eye. This makes for a very brilliant, or firey stone. A poorly cut stone will reflect a lot of the light out the sides of the stone, giving the stone a duller or lifeless appearance.
The other way the cut quality will affect the stone is how large it appears to be. A dealer will often refer to how the stone “faces up.” Some stones are cut very “heavy” or “deep,” which means that a lot of the stone weight is in the bottom of the stone. A deep stone also reflects light poorly, losing much light out the sides of the stone.
A diamond can also be cut very shallow, which makes it look larger from the top. A shallow 2.5 Carat stone may look like 3 Carats from the top, while a deep 2.5 Carat stone could look like 2 Carats from the top. Don’t be fooled though, because you don’t want to buy a shallow stone just because it looks larger. You may have a larger looking stone, but it will not have nearly as much brilliance as a well cut stone.