Princess cut diamonds are an example of a fancy cut diamond, offering a beautiful square shape that is both elegant and unique among the other diamond cuts. While princess cuts make up only about 5.3% of all diamonds on the market (based on current inventory figures), they are actually the second most popular diamond shape - beating out cushion (5.2%) and oval (3.8%). One of the major advantages of choosing a princess cut, beyond it's aesthetic, is the princes cuts slightly lower price point. Princess cut diamonds are considerably less expensive than their more popular sister the round cut (which makes up 75% of diamond inventory).
The main focus when choosing a princess is typically the length to width ratio, which should be as close to 1 as possible and no more than 1.05, if you are searching for a square cut princess. Rectangular princess cuts also exist but are not as typical as the square cut. This is a measure of how perfectly square the princess cut is - a 1.00 being perfectly square and a 1.05 being a slightly elongated rectangle whose longer length is 5% bigger than it's shorter side - thus becoming a slight rectangle (though unnoticeable to most people). Generally, most jewelers recommend you focus on finding a table between 65% - 75%, depth between 66% - 75%, with very good polish/symmetry. Unlike round cut diamonds, princess cuts do not have a GIA grading for cut quality. However, the AGS does analyze and grade cut quality for princess cuts and some jewelers like Brian Gavin and Whiteflash have a significant number of AGS graded princess cuts. Regardless, the most important factor in evaluating princess cut diamonds is to see them for yourself using high definition videos and images.
Princess is among the most popular diamond shapes, but still commands a significantly lower price point than round diamonds. Below is a chart depicting the price (y-axis) trend for a large population of H VS2 princess cut diamonds (GIA certified very good or better polish & symmetry). The price trend was solved using a simple regression on a the data set – our pricing algorithms use a more sophisticated machine learning algorithm than this model and incorporates several additional factors including each diamond’s specific dimensions. However, for studying simple price trend the below will paint a simpler picture. As you can see, a 1 carat H VS2 princess diamond costs approximately $4,300 while a 2 carat costs approximately $15,500. This exponential growth in price (the price more than doubled when the size doubled) is due to the diamond pricing metric that most jewelers cite when discussing value: price per carat. Every diamond shape exhibits a similar exponential price trend as carat size grows larger. This is summed up by saying, “the price per carat increases as the carat size increases”.
StoneAlgo always recommends you consider GIA Very Good or Excellent polish & symmetry grades for princess cut diamonds to ensure your diamond looks its best - but what about cut? The GIA does not currently grade the cut quality of fancy shapes like they do for round cut diamonds. Instead, as buyers we have to focus on some rules of thumb and, most importantly, visual appearance. Beyond simply recommending very good/excellent symmetry & polish, we conduct an algorithmic study of diamond dimensions to make sure that every diamond you see on our site is within the ideal table/depth dimensions. A general rule of thumb is that you don't want the table or depth to be above 75%, but many jewelers recommend a slightly more stringent categorization. When it comes to depth percentage in a fancy shape like princess, the percentage is calculated by dividing the depth by the smaller of the two width calculations, which can lead to an "overstatement" of the depth percentage for diamonds with higher length to width ratios. Regardless, the general consensus is that an ideal depth is between 66% and 75% with a preference toward lower depth percentages in this range. Some jewelers recommend you don't go over 75% for the table percentage and we've aggregated their advice to recommend a depth percentage from 65% - 72%. We would also like to recommend that you avoid diamonds with pavilion bulges like the one seen on the right side of the below diamond (source: GIA).
Princess cut diamonds aren't graded on cut by the GIA like round diamonds are, but the AGS does score the light performance of princess cuts and we recommend you check out some of Brian Gavin's amazing princess cuts if you want to see examples of high cut quality in a princess. Below are some general ranges StoneAlgo recommends for Princess.
When it comes to princess cut diamonds, we generally recommend that you begin by looking for an I or better color grade if you're choosing a platinum setting and a K or better color grade if you're choosing a yellow or rose gold setting. If you are going for a very larger carat size (say 2 carat or more) you may also want to consider better color grades. However, there are a lot of great examples of larger princess cut diamonds where an I color looks nice and white in a platinum setting.
Clarity is the toughest aspect of a diamond to judge simply based on a diamond’s grading certificate alone. Two diamonds of the exact same size and clarity grade can look totally different depending on the types of inclusions in the diamond and where they are located. Generally speaking, these differences in appearance are not relevant in the better clarity grades like FL, IF, VVS1, VVS2, VS1, and even VS2 clarity – though occasionally a VS2 clarity will not be as eye clean as you may expect it to be. On the flip side, SI1 diamonds can appear totally eye clean when they have inclusions in a certain location where it is less visible. Eye clean means that a diamond looks flawless without the aid of magnification from a jewelers loupe or microscopic lens. Here’s an example of a 0.71 carat I color SI2 clarity diamond that doesn’t appear to be eye clean (click to see a 360 degree video that shows the black speckled inclusion even more).
Diamond fluorescence produces a glowing property in some diamonds when they are exposed to ultraviolet light. To give an example of how prevalent fluorescence is in the diamond market, this affect is present in about 35% of the diamond inventory available at Blue Nile currently. Fluorescence is not necessarily a good thing or a bad thing, but like most things in life it’s good in moderation or in certain situations. For example, if you are buying a colorless diamond (D – E), then fluorescence may not be a good thing. But for diamonds grade I – K and lower, faint or even medium fluorescence can actually help the diamond appear whiter. Strong fluorescence is typically not recommended as it can make the diamond look hazy – so we’d recommend you stick with faint or none to be safe. You may have seen the designation negligible fluorescence which is the AGS grading equivalent to the GIA’s “none” qualification – representing diamonds that do not exhibit fluorescent properties.
One of the defining features of a princess cut diamond is its beautiful, square-cut corners. However, these delicate corners are both a blessing and a curse as they make the princess cut diamond more fragile than most other cuts. While you may be familiar with the diamond’s legendary status as “the hardest element on earth”, this is only true to a point. It really means that a diamond cannot be scratched by another element – it doesn’t mean that if you smash a diamond with a hammer it won’t shatter or break (it can and will). Placing protective prongs on each corner will help mitigate this risk and protect a princess cut diamond’s corners from harm.
That concludes our general recommendations for cushion cut diamonds. There are a lot of moving parts but generally speaking we try to maximize carat size for our given budget by sticking to the lower end of the color ranges we specified and searching for VS2 or better diamonds. SI1 diamonds are great if they’re eye clean, but they are a pain to find and often end up costing just as much as a VS2 diamond would. If you need one-on-one advice, we offer free support to all our users – simply drop us a line at firstname.lastname@example.org