Jump to content

Opinion on "RARE" Square cushion cut modified (ASET attached)


Recommended Posts

Background story is that I went into Tiffany's as a suggestion from a friend to try on every cut available to understand what I like.

I ended up loving their new Tiffany True, which is an "exclusive" cut but I've since found out it's known as the Aquila or square cushion cut modified. I had someone offer me this stone for about 7800 CAD total but don't know if it's worth it, what issues I may have, if the cut is excellent, why it's so low priced?

Using metrics from a general table I found online, some of the depth and table size % are larger than their proposed range... and it seems uneven on both sides (?)... any objective help would be appreciated!

Screen Shot 2019-06-20 at 19.01.06.png

Screen Shot 2019-06-20 at 23.34.40.png

Edited by cee92
Link to comment
Share on other sites

1. Using a set of geometrical proportions meant for round brilliants on a square/rectangular diamond cut to a "modified brilliant" pattern is not going to work. It's a bit like assessing a motorbike on a set of parameters meant to assess a car.

2. You are missing some of the most critical parameters anyway (i.e. pavilion and crown angles - which in a non-round need a different way of assessing in any case).

3. The GCAL "scales" for what they call "brilliance" and "optical symmetry" are ill-defined: GCAL has never published (to my knowledge) a definition of their scales beyond listing the 4-5 grades or of the parameters used to define the various grade boundaries, never mind the reason for choosing "those" boundaries and parameters.

4. Assuming the ASET-type image on the report is taken using a more-or-less standard ASET colour scheme and proportions, yes, it shows some unevenness left-to-right. Is it a deal killer? I don't think you'd notice it in reality vs. in a 5-10 x magnified and coloured representation.

5. The real problem with the "ASET" is that you have nothing to compare it against; you would need more diamonds with an identical cutting pattern and different proportions, and an understanding of how they look in reality vs. their ASET patterns.

Then you can apply your preferences for (e.g.) more contrast vs. more brightness and decide that ASET X with eight blue areas in the middle of a swathe of red is preferable to ASET Y with a fairly uniform mostly-green-with-some-red image. Sounds complicated? It isn't, really, but it is the process anybody needs to go through to establish a meaningful cut assessment system, and it's what a diamond trader goes through (plus or minus tools like an ASET lens) for every stone.

6. Final zinger. Have you noticed the little paragraph at the top of the middle section of the report, saying "lab grown diamond"? Followed by the longer paragraph under "Comments":


This is probably the main reason the price is out of line from others you may have seen. Synthetics go for significant (but not earth-shattering) discounts vs. mined stones.

Does all this make it a bad deal? Not necessarily, but make sure that it is what you want.

Link to comment
Share on other sites

@davidelevi first off, thank you so much for the clarification and help - it’s truly appreciated as I’ll be making a long commute Tuesday to see this diamond.


quick question would be whether the jewelry would be able to provide me those angles that are missing/critical? 

Secondly, would the jeweller also have access to ASET images of similar stones so that I can compare them? I imagine it will be difficult for me to find them online on my own because it’s such an odd cut. 


Thank you again! 

Link to comment
Share on other sites

You are very welcome!

14 minutes ago, cee92 said:

whether the jewelry would be able to provide me those angles that are missing/critical?

Unlikely, unless they are a very "tech-oriented" jeweller with a 3D scanner in the back office. 1 in a million... and in any case, if you are there and seeing the diamond, that trumps any theoretical considerations around a 40-to-41 degrees pavilion angle. Trust your eyes! Which leads us to the other issue:

22 minutes ago, cee92 said:

would the jeweller also have access to ASET images of similar stones so that I can compare them?

Unlikely - it's not a very widespread tool (though much cheaper than a 3D scanner, and you can buy one for yourself for $20 or so). But they should have something better: other comparable diamonds to look at. In fact, if I were you, I would make this a requirement for making the trip: if they arrange to have at least 3 similar diamonds to see, you'll go...

Link to comment
Share on other sites

GCAL images are decidedly different from the AGS-ASET ones. Aside from the color scheme, they have different angles coded into it so they highlight different things. As far as I know, only GCAL uses this scheme and they keep the details secret. That's sort of a feature. The problem with that is obvious but the benefit is that every GCAL image ever taken is by the same people, using the same equipment (more or less), with the same methods and rules.  Comparing one GCAL to another is much more standardized than it is with ASET, even with stones from different suppliers and even with images that were taken years apart.  As mentioned above, stores can't do it, not even techy stores.  

To a large degree, Tiffany costs more because they're Tiffany.  Their value-add comes from their history, their reputation, their quality control, etc. You may or may not value these things, but it's not a reasonable comparison to put them up against an online synthetic seller.  It's like comparing a new Ferrari with a used Hyundai and noting that the Hyundai is cheaper.  Yeah, it is.  So?

Edited by denverappraiser
  • Like 1
Link to comment
Share on other sites

@denverappraiser thank you for your help! I’ll also try to see if I can get comparable diamond shapes and their GCAL to compare to. 


I wasnt exactly trying to compare this diamond to Tiffany’s though, I was moreso trying to provide some background information on where this particular cut may have originated from... THEN ask if this particular synthetic diamond was a fair diamond to purchase at that price point/if there were any major issues you could find with the specs. 


Thank you again!! 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...