Princess Cut Diamond Guide

Last updated on December 16, 2021

Princess is one of the most popular fancy diamond cuts, favoured for its flexibility in working and sophisticated appearance. If you are interested in purchasing a diamond that offers excellent fire and brilliance, this princess cut diamond guide is a must-read.

History of Princess Cut Diamonds

The history of the princess cut traces back to the early 1960s when Arpad Nagy, a London based diamond cutter, designed the profile cut, which was often referred to as the princess cut at the time.  However, many believe that the true princess cut traces its roots from 1971 when Basil Watermeyer patented a new diamond shape and called it Barion cut. As a very complex cut, Barion proved to be extremely difficult to create. Incredibly symmetrical lines were a challenge even for the expert diamond cutters.

Nearly ten years later, another cut similar to the Barion was patented and named Quadrillion. The Quadrillion cut gained some popularity as it was easier to create due to its use of 49 facets compared to the 80 facets of the Barion.

The modern princess cut is a relative newcomer to the diamond world. It was created in 1981 by Betzalel Ambar, Ygal Perelman and Israel Itskowitz. A princess cut diamond can have as few as 50 facets, but the number of the facets is often modified up to 144 to maximize brilliance and sparkle. However, the “gold standard” princess cut features 58 facets.

Although the princess cut is traditionally a square shape with distinctive sharp corners, the shape of the cut is closer to an inverted pyramid with four bevelled sides; however, it can also come in tapered and rectangular shapes. The princess cut is the second angular cut, the first being the radiant cut, which has a complete brilliant-cut facet pattern both on the crown and pavilion. It is also worth mentioning that the grading reports describe the shape and the cutting style of the princess cut as a square modified brilliant or rectangular modified brilliant.

Princess Cut Diamond Cut Quality

The quality of the cut is the most important factor in maximizing the brilliance and fire, meaning it greatly affects the appearance of a diamond.

While the Gemological Institute of America (GIA) and other lab entities provide cut grading for the round brilliant cut, they do not give a cut quality grade for fancy shaped diamonds, including the princess cut. This is because fancy shapes have many non-standardised facet structures, meaning they can be cut to a wide range of proportions. However, grading laboratories list information on polish and symmetry which are some of the key features to choose a brilliant and sparkly stone.

When choosing a princess cut diamond, make sure to pay attention to the facets of the stone and their symmetry. The facets on the right and left halves should have the same shape. All the points of the facets should meet and there should not be missing or extra ones. Symmetry is the key to maintaining the overall beauty of the stone.

Since there is no industry-wide consent on what cut parameters make an ideal princess cut diamond, it is recommended to use the table below as a general guideline for evaluating the cut quality of princess cut diamonds.

Princess Cut Diamond Colour

The colour of princess cut diamonds is graded on a scale from D to Z, where D signifies a completely colourless stone and Z means an easily noticeable yellow or brown tint.

Since the princess cut is close to the round brilliant cut in terms of brilliance and sparkle, it tends to hide colour imperfections in the diamond rough, meaning it is harder to evaluate the true colour of the stone. This gives you the advantage to opt for a diamond in a near colourless range and still have a gemstone that looks colourless to an untrained eye.

As a general rule, smaller princess cut diamonds, those weighing 0.50 carats and less, hide colour better than the larger ones.  For this reason, depending on the size of a diamond you are about to buy, it is safe to choose a G, H, I or even J colour stone to have a colourless appearance.

The colour chart below provides a general guideline for evaluating colour in princess cut diamonds based on carat weight.

Princess Cut Diamond Clarity

The GIA grades clarity of princess cut diamonds on a scale from FL to I3, where FL means a flawless stone and I3 indicates a heavily included diamond.

In terms of clarity, the princess cut is similar to the round brilliant cut, meaning due to the arrangement of its facets and the excellent light performance, the princess cut tends to hide inclusions and blemishes fairly well, especially in comparison to step cut diamonds. As a general rule, it is harder to see imperfections in smaller princess cut diamonds than in larger ones, which is why you may opt for a lower clarity grade such as SI1 and SI2 if the stone is small enough to maintain an eye-clean appearance.

The clarity chart below provides a general guideline for evaluating clarity in princess cut diamonds.

Princess Cut Diamond Length to Width Ratio

The length to width ratio expresses how relatively long or wide a diamond appears. It is calculated by dividing the length of the diamond by its width. For example, if the length of a princess cut diamond is 4.3mm, and the width is 4.3mm, its length to width ratio is 1.00.

Each fancy diamond shape has a certain length to width ratio that is considered most appealing for that shape. Princess cut diamonds come in various ratios, from perfectly square (any ratio of 1.05 or less will appear square to the naked eye) to the more tapered shape. The ideal ratio for the square princess cut diamonds is 1.00, while the optimal ratio for rectangular shapes is between 1.07 – 1.15.

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