Princess Diamond - Cut

[Quattro33]

I'm going to try this question again since I think I was confused myself the last time I asked so it might have been unclear.

I'm shopping around for a princess diamond and I've been told by several jeweller's now that a "very good" cut is the best I'm going to see in this shape because they are not rated for cut in the same way that a round diamond is. I have, however, seen princess diamonds rated as "ideal" on various internet sites so I'm a bit confused.

I've been to a few independent jeweller's that have shown me only GIA certified stones at my request (i'm in toronto so a lot of jeweller's up here i've seen seem to favour gemscan stones and they don't seem to have a stellar reputation on these forums) and the certificates don't even comment on a cut grade so I don't even know where the "Very good" rating they keep telling me about is coming from!

Any help would be very much appreciated.

Thanks

 

[JohnQuixote]

Your confusion is very understandable.

1. The only major lab grading the cut of fancy shapes is the American Gem Society (AGS). Their top grade is AGS0, also known as AGS Ideal. What can be confusing is that some sellers will advertise a diamond as "ideal" in cut without an AGS report. This means the seller's interpretation of ideal is being used, not an official lab grade, and few interpretations will be as strict as the AGS standards.

2. The GIA currently does not grade cut for fancy shapes. A princess will not be EX, VG or any other grade in cut on a GIA report. There are jewelers who have long-maintained that finish grades (polish & symmetry) are equivalent to a cut grade but this is an outdated and inaccurate position: Finish can indicate the quality of care taken with the stone's faceting and polish, but it has nothing to do with optical performance.

The logical next-question is...how will I know how well a princess (or fancy shape) is cut?

It would be best to find some reliable top cuts to see with your own eyes. You may have a hard time finding AGS Ideal princess cuts in the mainstream though. This is because they require the manufacturer to spend extra time and effort to hit a rather narrow bullseye. As a result, only a tiny percentage of princess cuts are sent to the AGS - the vast majority go to other labs - and jewelers who don't carry AGS Ideal diamonds are not anxious to tell people about them. If possible, find an AGS0 princess and see what you think of the pedigree of that grade.

Become experienced at comparing stones to find the qualities you like - away from jewelers' lights (which make all diamonds look good). Of course, if you don't have a lot of experience and no top cuts to see as a benchmark you may just be comparing average cuts to other average cuts - which won't tell you a lot. In this case a trusted pro is always a good ally, whether it's a seller you have a relationship with or an independent appraiser.

If shopping online you should expect the seller to show proof of light performance via an ASET image, ideal-scope (tells a bit less) or other. These and actual magnified photos will demonstrate that the diamond is in the seller's hands and has the light performance pedigree claimed. Here, also, an intermediary like an appraiser can be relied-on, especially if dealing with a seller who provides limited info.

 

[Quattro33]

Thanks very much for your reply John. That information is by FAR the most useful i''ve found so far!

I''ll try asking the jewellers I meet for AGS stones from now on and see what kind of inventory they have.