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Emerald Cut Depth Question


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Hi everyone,


I'm a newbie looking at an emerald cut diamond (E, IF) with dimensions (8.3x6.9x4.8) for an engagement ring. The cert reports the depth as 69% which is (length/depth) and table as 59% and symmetry and polish as excellent.


The ranges for the AGA cut grading for 1A-2A is 60-65%, but I've seen other charts (diamondreview.com) where they cite a 60-76% range as excellent. I presume the confusion arises from comparing length/depth vs width/depth since the question is less relevant for rounds? If so, which should be compared to the old AGA chart? Is 69% too deep? Does having a slightly larger table and lower l/w ratio compensate for it?


Lastly, I know E/IF is pretty indistinguishable from a F/VVS2 at plain sight but am leaning towards getting a higher spec diamond since it would probably hold value better. Is that just foolish? Would a larger diamond be "rarer" and a better investment all other things being equal.


Thanks in advance and have a great weekend!



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Ah, the AGA cut grading chart!


The best use for these charts is at the bottom of a bird cage.

If you have no bird, then let's just throw them away altogether...heheh


Seriously- trying to make a chart declaring what's right and wrong about a diamond's cut- especially a fancy shaped one- is rather silly.

I mean, some people want a square-ish emerald cut, and others want a longer one. Who is right?

Of course neither desire is "wrong".


My point is that you'll need to see the diamonds- at least good digital images to get an idea if the diamond appeals to you.

The next subject, buying diamonds for investment. Bad idea.

I mean, diamonds do hold value better than most things people buy, but thinking of a diamond as a financial investment is a mistake.

I think E/IF is an awesome grade. It will be near impossible to tell the difference from a D/IF, except you'll save a lot of money.


Nothing wrong with F/VVS either!



When looking at emerald cuts- as opposed to rounds, which are all pretty much the same shape- you'll need to consider more than just the grade- you'll need to pick the diamond whose visual attributes please you most.

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Notwithstanding what David said about diamonds for investment being a bad idea (which it is), I suspect that in terms of resale you are most likely to get an easier time if you have a "middle of the road" G-I VS/SI diamond rather than a super-clarity super-white one.


When you talk of "larger" diamonds as in 10ct and above, then the rules of the game change. But so does the money.

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I am kind of inclined to agree with Diamondsbylauren on this one...I have to say that over the years I have done hundreds of custom searches for customers looking for great fancy diamonds, and although I can usually weed out the real "losers" from the pack by using depth and table measurements, I have seen stones that have the "perfect" depth and table, yet have terrible light performance, while stones that have measurements that I am not 100% on, have beautiful sparkle and beauty.


It really is something that you are going to need critical scientific analysis on if you want to go after a great cut. An Ideal Scope image and an ASET Image or model (generated from a Sarin or Helium) that is what is going to tell you how well the stone's light return is. Simply going on depth or table...is going to be about as good as shooting in the dark. I wish it were not that difficult, but it is.


As for the E/IF grade...great choice...visually indistiguishable from a D/IF and big price difference. From an investment standpoint...not a good investment. For an established retailer, who can buy diamonds at wholesale and sell them for retail, investing in a diamond inventory makes perfect sense. As an individual, who is going to have to invest a lot of time and energy into a resale, and most likely won't get retail price...not such a good investment. Also, as pointed out...E/IF stones are not the easiest stones in the world to sell.


As for IF vs. VVS2...Totally indistiguishable...however...I heard a great quote..."It is easier to find an eye clean stone than a mind clean stone." Sometimes you just have to go with what you want, and what you are most comfortable with. This is a big purchase, and you want to sleep well at night knowing you went with what you are comfortable with. Both clarities are great...now it is up to what will make you happier with your purchase.


All the best!


Tim A.

Emma Parker & Co.


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Thanks everyone! This has been really helpful.


It sounds like I should take my time and look at a lot more diamonds (and try to avoid buying sight unseen.) Do most jewelers have an ideal-scope and ASET on premises for clients to use or be willing to submit a mounted diamond for testing? Alternatively, does anyone know a good appraiser in London?


Thanks for the comments on color and clarity. What you've all said makes a lot of sense. I'd hate to buy something that looks great on paper but doesn't quite have the cut to optimize it.

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Hi All,

Ah, the old Ideal Scope, and Aset- now these are excellent as doggie chew toys. They are totally useless in judging Emerald cut diamonds however.....

KPM, my advice is to use your eyes.

If you are dealing with someone local, make sure you feel comfortable and look at the stones, It's not brain surgery, you'll know what you love.

If you are considering an online purchase, again, find someone you are comfortable with, this is important.

Of course with an online purchase, photos are essential.


Here's a recent listing of ours....


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I actually find ASET, and to a lesser extent IS, to be useful in looking at and documenting stones. It’s the photographs that I have a problem with. They just aren’t standardized enough and without knowing under what conditions the picture was taken and how it’s been handled afterwards it’s all highly suspect data. This is true of plain faceup views as well. It’s relatively easy to produce a photograph that conceals as much as it reveals. If you’re comparing several photos of different stones taken by the same source where you can reasonably trust their methodology they can be helpful but taken out of context or presented in isolation they loose most of thier merit. Put another way, when comparing one stone to others being offered by the same dealer they can be useful but comparing two or more photos offered by multiple different dealers or, even worse, looking at a single picture in isolation they aren’t all that helpful.


And besides, they would break into sharp pieces of plastic and you might injure your dog. Stick with tennis balls for that use.



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You're 100 % correct- Please everyone- do NOT use the ideal scopes as doggie toys.


But I'll tell you this- take out the pink part, and it's a darn good shot glass!

All due respect, but the Ideal Scope has no use whatsoever with an emerald cut.

If you want to demonstrate hearts and arrow on a round diamond, then maybe it might work if the Bourbon didn't melt the plastic ( heheh)


ASET and Sarin are clearly a different story.

Sure, there's value in having precise measurements of a diamond. But I believe the value comes from being to document a diamond already in consumers hands- rather than as a tool by which to select a diamond.


I agree too that photos can be, and often are misleading.

ON the other hand, there are a lot of photos being used that are more representative. Many of the sites that have photos can show the imperfections in close ups, for example.

But when it comes to fancy shapes, there's some things a photo can also show - the actual shape.

I agree that the photos must be judged in context.



For reference: The diamond I posted has a GIA report - no sarin for this one- but there's some things the photos does seem to show ( of course I looked at the actual diamond, so I can correlate what I'm seeing)

WEIGHT: 2.76ct

SHAPE: Emerald Cut



MEASUREMENTS: 9.27 x 6.98 x 4.48 mm






GIA REPORT #: 16881977


I can see the Fluorescence in the photo.

I can see the shape.

I can see the facet pattern.

I likelarge corners on an emerald cut- I can see those.


I would never presume to grade a diamond using a photo, or series of photos- but they can be used for demonstration of impefection.

Here's another of the 2.76ct


This is an SI2 diamond that has a small imperfection possibly visible, and demonstratable in these photos- I can see it.

It's close to the center at about 4:00



KPM- As yo you look at stones, here's a few things I look at- and we look at a lot of large ( 1ct and up) emerald cuts for stock.

1) Corners: The largert hte corner, the larger the ytriangular facets- giving a lot of personality

2) Sparkle and Glitter. I love the "hall of mirrors" effect Nicer emerald cuts broadcast this while many of the bad ones I've seen are just dark in the center.

3) Shape- do you like square, broad rectangular, or a taller profile?

Edited by diamondsbylauren
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