The princess cut is one of the most popular diamond cuts. It is considered an alternative to the round cut, and for good reason: Just like it, the princess cut is a brilliant cut, only with a different shape. But what are the characteristics you should focus on when assessing this type of cut?
Princess Cut Characteristics
Princess-cut diamonds are rectangular in shape. Usually, they have a square profile.
The most important specifications on which a princess cut is evaluated are its girdle, length-to-width ratio, depth and table percentages, and the presence of a culet, as well as its size, if there is one.
Let’s take a more detailed look at these quality characteristics:
The girdle of a diamond is its widest part.
This outer edge can have a thickness grade that ranges from Extremely Thin to Extremely Thick.
For princess-cut diamonds, the optimum girdle thickness ranges from Very Thin to Thick.
Diamonds with Very Thick girdles are undesirable because their other proportions are distorted due to the overly large girdle.
Extremely Thin girdles are also to be avoided because they are vulnerable to chipping.
Length-to-Width Ratio for Princess Cut
The length-to-width ratio of a princess-cut diamond tells you how close its shape is to square. The length and width of a princess cut are measured along the girdle.
Usually, the length-to-width ratio in princess cuts is around 1-1.1. Values closer to 1 are more desirable for this type of cut, whereas ratios above 1.1 are less sought after.
Depth Percentage for Princess Cut
The depth percentage of a princess-cut diamond is calculated by dividing the depth of the stone by its width.
It is best if this value is between 65% and 75%. Values in the 58%-64% and 75%-80% ranges are also considered good.
Princess cuts with depth percentage values below 58% and above 80% are considered fair or poor quality.
Table Percentage for Princess Cut
The table percentage is calculated by dividing the width of the topmost facet (the table) by the width of the stone as measured along the girdle.
A table percentage of 60%-75% is considered best for a princess cut. Diamonds with tables in the 75-80% or 56%-60% range are also considered well cut.
In general, avoid princess cuts whose table percentage is higher than 85% or lower than 55%.
The culet is the small flat facet on the bottom of a diamond. Often, the culet is missing, and the bottom is simply a pointed end.
It is best if the culet is small or if there is no culet at all. (Some people prefer to have a culet because they think sharp diamond bottoms are more likely to chip.)
Medium to large culets are undesirable because they are too visible when the stone is looked at from the top and spoil the appearance of the table’s light pattern.