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The Princess Cut Diaries (How to select the most beautiful Princess Cuts)
For those of you who have spent time browsing the diamonds we feature you'll know that we just don't post or purchase for inventory the common types of stones that are sold in most stores or websites. Our aim is to select the most aesthetically beautiful stones utilizing the latest and best technologies for the task as we can ascertain and separate the most brilliant princess cuts from the least. The #1 question we get asked most frequently is ... "What proportions constitute an "Ideal" princess cut? Thankfully AGS has undertaken the task and very recently (as of May 1st 2005) starting issuing lab reports on princess cuts and have designated an "ideal" grade which is very hard to attain. Most factories cutting princess cuts do not send their goods to AGS for the most part so those that have the gumption to do so must be very confident in what they are cutting. We'll see how this plays out. While the expression "Ideal" just started being applied to certain princess cuts (only from AGS) this tutorial is being written during a major transition that is taking place within our trade. Both GIA and AGS Labs are completely revamping their cut grading systems and AGS' first implementation with this new cut grading system will, of all shapes, be applied firstly to princess cuts (effective May 1st 2005). When this system is released we will be updating this tutorial as necessary and comparing the results of their studies with that of our own. So far, the limited information that has been given to us from AGS shows a nice correlation between what we have found and what they have found. At this point it appears that we are very much on the same page. We'll be breaking down this tutorial into a number of chapters. The first 2 which are included on this page. In the upcoming weeks we'll be adding the others.
Where to begin? Well ... lets start with the current market situation. Since there is currently no standard definition for what constitutes "ideal" for princess cuts, cutting houses are generally guided by one philosophy which dominates throughout most cutting houses. Get the most yielded weight from the rough as possible with little or minimum regards for proportions that will produce high brilliance. The result? Generally stones with total depths or tables that are in the high 70's to low 80% range resulting in either bottom heavy or top heavy stones with shallow crowns. Either of which produce brilliance and light return that 99% of the time is less than ideal. :( A current search from one of our wholesale databases produces the following results...
Heh... if this all looks Chinese to you American's... don't feel bad. When it comes to selecting princess cuts with the best light performance it's all foreign to us too based on this limited data! Things to take note of on this list.
With the current cut philosophies/practices of most cutting factories, finding the best princess cuts then becomes quite a daunting task. Finding the needles in the haystack so to speak. So ... how do we begin to sift through the batch to find the most excellent goodies? Step 1: Choosing princess cuts from a conservative lab whose tables are less than their total depths. Being that the information is very limited on GIA Reports for princess cuts the only metrics we have to go by on the lab reports is
While all the info is relevant the 2 metrics that primarily concern us in step 1 are the table and total depth measurements. In the realm of ideal cut rounds (according to the new GIA/AGS standards, few ideal cut rounds according to the current grading standards have tables that are equal to or greater than their total depths. While total depth % used to not be taken into account to determine an ideal cut round the best ideal cut rounds have depths ranging from 60.5% up to around 62% with tables always being smaller (52.4-57.5%). Likewise in princess cuts our findings show we stand a much better chance of finding a high performing princess cut when the table is less than it's total depth measurement. We'll generally start by looking for princess cuts whose depths are no greater than 76% (preferably lower if possible) with smaller tables. So if the girdle, culet, polish & symmetry are acceptable and the stone is graded by GIA or AGS and lets say it has a 72% depth with a 67% table ... we're off to a good start! :) IMPORTANT NOTES ON THIS STEP: This is not a hard fast rule. There are beautifully performing princess cuts whose tables are equal to or greater than their total depth, however we greatly reduce of chances of finding the *cherries* amongst stones with those parameters. Some people have taken this rule of mine on the net and have disqualified stones based on this rule alone or have quoted me out of context. If the company you're doing business with is offering a diamond whose table is => the total depth measurement and can demonstrate why the stone has superior light performance (we'll be getting into analysis in a second to learn how to determine this), then by all means you should consider such a stone. The most recent information we've received from AGS (1st quarter 2005) confirms our own findings. Ie. The more the table becomes => the total depth, the less your chances are of finding a princess cut with the best light performance. Step 2: Call in the rock! NEVER ... I repeat ... NEVER purchase a princess cut based on step one alone. I've witnessed people do that and toss thousands of their hard earned dollars out the window. If you're not going to follow through with the rest of the steps outlined here then you're defeating the purpose. Why call the rock in for exam with a pro? Many obvious reasons. Our primary reasons are for optical testing. We encourage you to do business with firms featuring optical analysis (especially for non AGS diamonds). The more exams the better. Here at "The Ultimate Diamond Information Site" we utilize 4 primary tools for the task which we consult on each and every purchasing decision. Let's take a look at each of these with some detail and then we'll begin to examine the results of various proportions in princess cuts. The Right Tools for the Job
Now lets begin to look at some examples and I'll be giving you step by step commentary on each piece of information as we get it. The Case of the Table being Less than the DepthExample #1: 1.02ct E VS1 Square Princess Cut Upon first inquiry we were able to get the basic GIA information. Notes to point out on the report:
So far ... no red flags and we're off to a good start.
Sarin data: When examining Sarin data on a princess cut, knowledge of two sets of crown and pavilion angles must be attained if the rest of the optical exams can't be performed. Most companies can not provide those two sets of angles which is why posting Sarin results on a princess cut is not effective for ascertaining optical performance at this point in time. The Sarin DiaMension hardware coupled with Sarin DiaVision software produces the following results for this stone Crown height of 11.5% (green flag) When examining basic Sarin data we generally like to see crown heights of at least 10% and pavilion depths in the mid 50's to low 60% range. Once again, this isn't a hard fast rule but a good indicator. If I see these further green flags from basic Sarin data, all the more reason to call in the stone. Not all suppliers have Sarin or OGI machines to give proportion information so many times we don't even get this from a supplier. We usually gotta call it in.
For your own information, in AGS' upcoming grading system for princess cuts the total model of the diamond will be assessed. AGS has released "cutting guidelines" for princess cuts and once table size has been determined here are the 2 sets of angles needed to help ascertain performance which we have outlined in red (set 1) and blue (set 2). In the upcoming months having this data will be handy for non AGS stones but until then ... let's proceed with our exam.
In short, when I'm looking at Sarin data I like to see a nice crown height (preferably over 10%) coupled with a pavilion depth in the neighborhood of 60%. This stone was close so I decided to call it in for an optical exam. LightScope Exam: reveals a nice amount of dark reds and blacks (for a princess cut). In brief ...
There are some areas of leakage within this diamond however it is predominantly saturated with dark reds and black. Is the light being reflected back at a high enough intensity for us to consider purchasing for inventory? BrillianceScope results: HECK YEA! :) While we do look at the bar graph (2/3 Very Highs) there is much to be learned from the images the BrillianceScope produces on the diamonds it tests. Each light view (1-5) shows excellent activity in each position. This is enough information to know this ones a keeper. Examining this with the eyes confirms one of the most beautiful and rare princess cuts on the market. 
Finally here is it's MSU results. At the time of this publishing we do not yet have a tutorial on this technology but will be featuring one (as soon as I get this princess cut tutorial completed). :) Note the scores for light return. .84 (mono) & .85 (stereo). This has been a consistent reading from the MSU scores regarding excellent performing princess cuts. Further investigation also reveals that this is diamond qualifies as a princess cut with AGS ideal proportions.
Let's proceed with another princess cut whose preliminary information was similar to the stone above. Example #2: 1.04ct D IF Square Princess Cut When we inquired about the GIA information on this stone it had a table/total depth combo of 71.3% total depth with a 67% table. The diamond in the first example had a 71.2 depth with a 67% table. So ... as you can see I was feeling pretty good about this stone. :) We did not save the GIA Report on this stone so we don't have the scan on it but here is a screen shot of the Sarin.
As you can see this also has many similarities to the first example. 11.7% crown height (green flag) LightScope results
Not a bad image at all. There is more leakage taking place within this diamond (not that much though) PLUS there aren't as many blacks as observed in the first example. A little tricky, however the BrillianceScope reveals these results. 
Now ... this isn't an example of a crapper. This stone happens to be a decent stone, just not the best. Within BrillianceScope results, we're looking at least for very high colored light return with the other metrics getting highs. We wound up turning this one down. Here is this stones MSU results.
A side by side comparison of these results shows that only when we get down to the brass tacks of the optical tests do we see what separates the ideals from the non ideals.
Final note on the ASET views. The 1.02ct E VS1 displays a superior amount of reds and blues (light entry/exit at high angles) and better optical symmetry. As of this writing another interesting thing to point out (which is going to change in the next release) is that the MSU software rewards a diamond with a higher contrast score when more leakage exists. Yes, this doesn't exactly make sense but take note of the higher contrast score on the 1.04ct D IF. This is because it is leaking more light and is the inferior of the 2 cuts in this example. Next chapter ... How to identify an "Ideal Princess Cut" according to the AGS charts.
Not finding what you are looking for? We have many diamonds available to us through our suppliers. Our staff would be happy to assist you in your search for the perfect diamond. You can tell us exactly what you are looking by contacting us at the link below. We look forward to serving you!
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