Cut
Princess cut diamonds can have different facet patterns and do not receive an assigned cut grade from GIA on grading reports like a round diamond. Because of this, it can be hard to assess a princess cut diamond’s light performance purely by looking at the numbers and not seeing the diamond in person.
The variations are based on the way the pavilion and crown facets are cut with the pavilion having configurations of two, three, or four chevron patterned facets. This is important because the brilliance of a diamond increases with additional sets of facets, and light dispersion unfolds differently in each configuration. The two chevron pattern creates a very bright diamond with lots of sparkle and less scintillation. The three chevron pattern has a very desirable balance of brilliance and dispersion of light. The four chevron pattern creates an intense fire and scintillation, but the light dispersion is less defined giving a “crushed ice” effect like in a modern cushion cut.
The crown of the princess cut is cut between two styles: a bezel facet cut from the corner of the table to the stone corners, or a French corner where the facets on the table point to the corners. The differences between the crown faceting style is usually dependent on the cutter’s preference. The important thing to remember about the corners is that they are fragile regardless of the cut style, so need a setting to protect them.
The princess cut is known for its square shape, but there are length to width ratios to be found that extend into a slightly rectangular appearance. The preferred ratio is generally accepted as between 1.0 to 1.05. This range would make it fairly impossible to tell if the diamond was ever so slightly off-square. Moving above this range, you could likely find princess cuts with a ratio of 1.06-1.12 and these would have a more easily perceived rectangular look.
Color
Since the princess cut employs the brilliant cut faceting technique, it will succeed in chopping up light so the color of the diamond rough is harder to perceive. However, it has less superior light return than the round brilliant and typically more depth where color can hide, so there is more of a possibility that color can be noticed.
Typically, a well-cut princess cut diamond will exhibit fire and brilliance that will hide body color and help mask inclusions. Color is also highly subjective and should be left to personal preference. Where one person may prefer a cool, icy white in their diamond, another may be much more drawn to the warmth of some color being noticeable in the stone.
Clarity
All diamonds have slight imperfections and the most important thing to remember about clarity is to look for a diamond that is eye-clean to the naked eye. For a princess cut diamond, it’s also important to steer clear of imperfections located near the corners of the stone. Because of the angular nature of the corners, they are already more susceptible to chipping, and any inclusions located there will further hinder the stone’s integrity.
Since so much of the diamond rough is kept when cutting a princess cut, it’s not simply a case of cutting around imperfections and blemishes during the process. This isn’t to say that princess cut diamonds are more prone to exhibiting inclusions, but it may be harder to find an eye-clean one in better clarity grades because it would mean the diamond rough was of exceptionally high quality to begin with, and that’s rare.
Carat
Princess cut diamonds are available in a variety of carat weights. Similar to round brilliant diamonds, the princess cut diamond tends to have linear changes in carat size and dimensions. This means that increasing weight and size of a princess cut diamond will tend to move together in a linear pattern.
These diamonds also have the benefit of appearing larger for their carat weight and size. Their large diagonal measurements draw the eye outward to the corners, effectively stretching the look of the stone. However, because of their greater depth, more weight can be distributed deeper in the stone instead of towards the surface.
