Got Diamond Questions?
Our community of diamond experts are here to provide answers
npana

Emerald proportions

Recommended Posts

Hello all,

Have been looking for an emerald cut, F colour, VS1, 1.40 - 1.50ct stone with 1.4 - 1.5 ratio... 

The ideal proportions seem to be the table length at 61 - 69 and stone depth at 61 - 67. The GIA report also states the girdle thickness, symmetry and polish.

Wondering if there is any other criteria with the emerald cut such as, angles or pavilions to help narrow my search ?

Thanks,

NP

Edited by npana

Share this post


Link to post
Share on other sites

There is no such thing as "ideal proportions" for an emerald cut, not least because the cut itself is not standardised enough; the numbers you have above are unlikely to be much help: they will generate a lot of false positives (duds that have the "right" numbers) and a few false negatives (nice looking stones that have the "wrong" numbers). AGS has developed models of cut assessment for non-round shapes, but lab reports from AGS on emerald cuts including cut grade are way rarer than hen's teeth.

The only valid criterion for assessing cut is looking at the stone(s); if you can do that in person, even better, but good quality photographs (many, not one), video and reflector images can help. If you are considering multiple stones, comparative video (all stones in one video shot in different lighting condition) is definitely a good resource; more than ever, pick the vendor before you start picking stones: not everybody is/can be equally helpful.


Davide - Specialised Consumer Information and Assistance,
Diamonds by Lauren (http://www.diamondsbylauren.com)
davide@diamondsbylauren.com

Share this post


Link to post
Share on other sites

Just been reading on internet sites about depth and table lengths and these seem to be the preferred. I agree visual is the ideal

Thanks again

 

Share this post


Link to post
Share on other sites

Visual inspection, as stated above, is key.  In the process you should make a not of the proportions that appeal to you the most.  You may like fat rectangular stones in the 1.1:1 ration range or longer stones in the 1.5:1 range.  There is no right or wrong except that you should choose something you like rather than be convinced by a sales pitch. 


Laurent George
Diamond Ideals
New York City

www.diamondideals.com
212-207-4845
laurent@diamondideals.com

 

 

Share this post


Link to post
Share on other sites
9 hours ago, npana said:

Just been reading on internet sites about depth and table lengths and these seem to be the preferred. I agree visual is the ideal

Thanks again

And now you are reading on another internet site that depth and table are largely irrelevant. Who may be right?


Davide - Specialised Consumer Information and Assistance,
Diamonds by Lauren (http://www.diamondsbylauren.com)
davide@diamondsbylauren.com

Share this post


Link to post
Share on other sites

I am starting to have a little more faith in my own visual judgement and not focus too much on the numbers.

  • Like 2

Share this post


Link to post
Share on other sites

The numbers are guides to be used to give you a general idea of what the stone is going to look like.  As there are no agreed upon set of numbers that qualify as ideal for emerald cuts, the best you can do is use the numbers to rule out known duds.  a stone with a 2:1 length to width ratio for example will look like a baguette and is generally considered too long to be a pretty emerald cut.  But you may happen to like that shape.  The same can be said for table and depth percentages.  I will tell you that a wide open table (>65%) and a shallow depth (<59%) is going to give you a glassy looking stone with little to no life. And a super deep stone (>70%) with a tiny table (<55%) is going to look substantially smaller than a stone should because all the weight is in the depth.  It's the combination of these that becomes very personal and virtually impossible to quantify consistently.  I personally like emeralds in the 1.35 to 1.5:1 ratio with a mid 60s depth and a table in the low 60s to mid 50s.  But that's me.


Laurent George
Diamond Ideals
New York City

www.diamondideals.com
212-207-4845
laurent@diamondideals.com

 

 

Share this post


Link to post
Share on other sites

D is completely colorless.  As you start adding incremental color, although still considered colorless, E and F start having hints of color.  If they didn't then they would be Ds.  The most common shade stones tend to is yellow but sometimes they can be brown.  I doubt the information on this link comes entirely from a GIA report.  Some of it may be in-house grading and some of it may be leftover fields from a different stone.  I noticed the stone has Hearts and Arrows according to this link, which is quite a difficult thing to achieve in an emerald cut.


Laurent George
Diamond Ideals
New York City

www.diamondideals.com
212-207-4845
laurent@diamondideals.com

 

 

Share this post


Link to post
Share on other sites

Never seen FBR on a F graded stone but you may be right. ill confirm with the supplier if its an error

Thanks

 

Edited by npana

Share this post


Link to post
Share on other sites

As you said, this is not mentioned on the GIA report, so the only source would be internal and not necessarily as reliable.


Laurent George
Diamond Ideals
New York City

www.diamondideals.com
212-207-4845
laurent@diamondideals.com

 

 

Share this post


Link to post
Share on other sites

Just find it strange that a supplier would "lower" the stones colour when GIA have graded it and F. Unless of course its an error.

Share this post


Link to post
Share on other sites

GIA would not grade a stone "faint brown" until the brown tint reaches at least K. Any colour other than yellow, brown or grey would be reported using the fancy colour scale, not the D-Z scale.

I too think it's an error, but it's also possible that the vendor thinks it can detect a brown (rather than the more common yellow) tinge - I wouldn't see this as a "lowering of the colour grade".


Davide - Specialised Consumer Information and Assistance,
Diamonds by Lauren (http://www.diamondsbylauren.com)
davide@diamondsbylauren.com

Share this post


Link to post
Share on other sites

It sounds like an error but dealers are welcome to use additional scales if they want. This is not the only thing on the ad that isn't from GIA. Nearly half of what they show comes from elsewhere. There are also areas where they disagree (look at the girdle for example) 

If they don't provide a scale and an explanation of their grading terms, what they mean and where the got the data, don't just ignore them, hold it against them. 


Neil Beaty

GG(GIA) ICGA(AGS) NAJA

 

There's never a crowd when you go that extra mile.

Professional Appraisals in Denver

Share this post


Link to post
Share on other sites

While GIA may report browns at K, the suppliers may do that for all stones. A D can also be brown. Essentially anything better than an E is a D. It's rare but it's possible. This is done to ease the buying for the buyer and possible any future dispute. Brown stones are discounted compared to their normal yellow counterparts. The brown-ness is easily visible at H color and below. 

The hearts and arrows field is empty. Normally for round stones it would have something like EX, VG, N, Y or something like this to describe the symmetry. But no way does it mean that the stone is hearts and arrows according to our modern standards. 

The cut grade is probably just some arbitrary standard - could be in house or could be any lab other than GIA. You will see it describes the cut as Excellent plus :D


Swanstar Diamonds.
http://www.swanstar.com.au
Melbourne, Australia.

Share this post


Link to post
Share on other sites

Hence why this stone is offered at a good price. Thanks for all the feedback. I Will say no to his stone if the faint brown is evident 

 

Share this post


Link to post
Share on other sites

Hello again,

Firstly, thank you again for everyones feedback and I realise now with emeralds there is no cut that defines a beautiful stones...beauty is in the eye if the beholder.

I have found a stone that looks great and would like to order it but not too sure how to read the asset and hope to avoid the hassle with returning if it is dull .

Also, would medium blue fluorescence be an issue with D colour ?

Thanks

NP

526957962Real.jpg

526957962AssetScope (1).jpg

Screenshot_20180910-083801_Drive.jpg

Share this post


Link to post
Share on other sites

Assuming the ASET has been taken properly (and I have my doubts it has), it's OK but not great: it seems to have insufficient contrast in the middle (for my taste, at least). Can you get a video of the stone?

Re: fluorescence - it will cause no issues other than making it significantly more difficult to resell, which is why it's going at a discount now.


Davide - Specialised Consumer Information and Assistance,
Diamonds by Lauren (http://www.diamondsbylauren.com)
davide@diamondsbylauren.com

Share this post


Link to post
Share on other sites

FWIW, and this is my personal opinion only, it is a bit "flat" - while it's a bright stone, it doesn't give the nice alternance of bright and dark that I find so attractive.

Here is one that does - not a recommendation (and not within your search space anyway), but just to demonstrate the difference

https://www.jamesallen.com/loose-diamonds/emerald-cut/1.68-carat-g-color-vs1-clarity-sku-5629206


Davide - Specialised Consumer Information and Assistance,
Diamonds by Lauren (http://www.diamondsbylauren.com)
davide@diamondsbylauren.com

Share this post


Link to post
Share on other sites

Same observation; nice and bright, but a bit flat.

Side note on video technique:

It would have been good if they took the video with more than one complete 360 degree turn. As they have done it, the critical observation area of +/- 20-30 degrees from "dead on center" is split at either end of the film, and it's harder to imagine what the stone looks like in real life (think of how you are likely to see the stone: more or less on centre, but with some difference either side - right now the 20 degrees from the left are at one end of the video, the 20 degrees from the right at the other end, and you cannot "rock" the stone virtually from one side to the other, which is what happens in reality).

ETA: I'm glad that you can see the difference. Please bear in mind that this is not meant to demonstrate what you should like; only what I like. If you happen to prefer a more contrasted stone, it's fine (and it suggests that you should look for another stone). If you like the more uniform look of the stone we are discussing, it's fine too - and you have found something you like already.

Edited by davidelevi

Davide - Specialised Consumer Information and Assistance,
Diamonds by Lauren (http://www.diamondsbylauren.com)
davide@diamondsbylauren.com

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now