Excellent HCAs on these, yet when does the ASET image become unacceptable (clearly not Hearts and Arrows) ?

[LSG]

Good day !

The following three diamonds are all possible choices for us, all with GIA Cut/Polish/Symmetry Excellent, Culet none. No comments on the GIA certificate (except : "Minor details of polish are not shown").
The HCA is E+E+E+VG=Excellent, yet the ASET images are not great.

Are any acceptable ? Any unacceptable ?
Are all AGS 0 ?

HCA 0.7, Table 56, Crown 34.5, Pavilion 40.6, Depth 60.5; 15.0, 2.5, 42.5



HCA 1.1, Table 56, Crown 34.5, Pavilion 40.8, Depth 61.7; 15.0, 4.0, 43.0




The above two with the same scope and technique, the next with another.

HCA 0.8, Table 57, Crown 33.5, Pavilion 40.8, Depth 61.2; 14.4, 3.5, 43.0





When an ASET image is an exceptional Hearts and Arrows all is clear.
When it is poor, the example shown is very poor.

There are few articles that treat ASET images of diamonds which apparently have Excellent to Very Good light performance, yet with disturbed Hearts and Arrows, presumably due to some painting and digging or other enhancement techniques.
Pricescope has several good articles on Hearts and Arrows !

Best regards !

 

[Karl_K]

hca score, gia ex, or ags0 does not mean they are h&a
The biggest issue is the aset images are not well taken.

 

[Garry H (Cut Nut)]

The top image is heavily painted and will lack contrast.
The middle stone has really poor symmetry.
The bottom stone is the pick.

 

[John Pollard]

Hello @LSG

I wanted to elaborate on the comments above.

Good day !

The following three diamonds are all possible choices for us, all with GIA Cut/Polish/Symmetry Excellent, Culet none. No comments on the GIA certificate (except : "Minor details of polish are not shown").
The HCA is E+E+E+VG=Excellent, yet the ASET images are not great.

In my opinion the ASET images all show great light return.

Are any acceptable ? Any unacceptable ?
Are all AGS 0 ?

The proportions sets are all predicted to earn AGS 0 light performance, according to the AGS cutting guides. Based on their ASET images I don't see anything that would disqualify them. Technically the only 'official' AGS 0 comes by having them pass through the lab, but the answer to "Are all AGS 0" from me is a qualified yes.

When an ASET image is an exceptional Hearts and Arrows all is clear.
When it is poor, the example shown is very poor.

ASET shows Light Performance. H&A is another thing - a matter of Optical Precision - which @Garry H (Cut Nut) calls symmetry above.

An ASET image doesn't need to show perfect Optical Precision (arrows-patterns) for the diamond to be bright and earn AGS 0.

I think you're making a very good observation - we tend to see a lot of "role model" examples of ASET images which combine top light return/performance with top Optical Precision. But a diamond doesn't need to have perfect H&A (Optical Precision) to be bright and earn AGS 0.

There are few articles that treat ASET images of diamonds which apparently have Excellent to Very Good light performance, yet with disturbed Hearts and Arrows, presumably due to some painting and digging or other enhancement techniques.
Pricescope has several good articles on Hearts and Arrows !

Best regards !

Thank you. This is a good call-out for an article on differentiating what ASET images are revealing, separately from H&A.

 

[LSG]

Thank you all for your comments !

As a 'novice' who buys very nice diamonds every 5 to 10 years (on major occasions) your comments are very helpful.
Thus, the following is for now, and for our next purchase based on an article to appear before five years from now...

To John Pollack, it would be great to have an article that deals with the 'upper-mid' range of potentially great light return performing stones.
When is an ASET image very, very nice (yet not Hearts and Arrows) ?
When does it become 'unacceptable' ?
When is the apparent image, as taken, so poor (as suggested by Karl_K) as to totally disregard what it is showing ?

To Garry Holloway, the first ASET image did seem to us to not have too much contrast, so effectively it was not 'the best-of-the-best in the world'. Still, there doesn't seem to be hardly any light 'leakage' (at all). With the on-the-nose Excellent Cut proportions, Symmetry/Polish the light/fire/spread should be very, very good.
Effectively, Hearts and Arrows do not exist, surely not 'black' ones.
To a novice, the notion of 'painting' (and 'digging') is clear yet how to spot the degree on an ASET imageand their effect on 'desirability' and 'value' are unclear (given that apparently it is not extensive enough to mention on the GIA certificate).

The second ASET image did not look great, to say the least, despite the Ideal cut.
Still, some articles called the spot light leakage at the angles potentially sparkle 'enhancing' leakage (sounds subjective...).
[And, the relative price per carat did reflect a modest discount (less than 10%) from the first image (mentioned for accuracy, only a secondary criteria).]

The third ASET image seemed to have a slightly tilted table, or was not well mounted (We have other images which imply it is an ever-so-slightly tilted table).
To a novice it is hard to state that the symmetry is better on the third image.
The red is more uniform, yet the technique is different (what role does that play ?).
The contrast arrows are not uniform and often have adjacent areas of contrast (too important/severe ?).
There seems to be more clustering near the culet (important in the choice, or not; cut-related, shallow Crown angle ?).

We may keep looking for another stone, for a little while.

Thank you all !

Best regards,

LSG

 

[musicloveranthony]

I've noticed different vendors seem to get different levels of scrutiny for their ASET/Imaging. That makes it hard for newbies or visitors to know what to believe and what not to. I've seen uglier ASETs with encouragement that nobody could see the imperfections without a microscope. It's hard for a skeptical person to not wonder if that isn't to intentionally route toward sponsoring vendors.

None of these are abysmal - they're all better than most diamonds on the market. None of them are super ideal. Acceptable is up to the customer, and I think too often I see level of acceptability being based on vendor criteria first.

Also curious if LSG should be a trade member since it seems that's the case

 

[Garry H (Cut Nut)]

The slightly tilted table is not a problem. It can even still show H&A's if all the pavilion and crown SYMMETRY line up (which is the factor that causes the H&A's patterns).
The first stone is probably H&A's but it LACKS CONTRAST like Eight Star Diamonds did.
John is inaccurate in separating optical symmetry from actual symmetry. Also Hearts and Arrows can occur across a huge range of proportions - most of which are pretty shocking to lovers of them.

 

[Karl_K]

1st image: everything is not centered correctly with each other but can tell the diamond "probably" has excessive painting and digging.
2nd image: it is not possible when everything is aligned correctly for a diamond to look that way. There would "probably" be some issues shown with a properly taken image.
3rd image: again it is impossible for it to look like that when everything is properly aligned.
"probably" the best cut of the 3.

3 "probably" answers, if that helps.

 

[Karl_K]

I've noticed different vendors seem to get different levels of scrutiny for their ASET/Imaging.

ASET images are about interpretation and I and a handful of others can mentally work around some image problems, some we cant.
With these images I'm not above a "probably" answer even applying mental compensation for some of the issues.
Some vendors all their images have the same issues and we have other images and video to double check things. That makes it much easier to tell what is going on with less than perfect is/aset images.

 

[Garry H (Cut Nut)]

To Garry Holloway, the first ASET image did seem to us to not have too much contrast, so effectively it was not 'the best-of-the-best in the world'. Still, there doesn't seem to be hardly any light 'leakage' (at all). With the on-the-nose Excellent Cut proportions, Symmetry/Polish the light/fire/spread should be very, very good.
Effectively, Hearts and Arrows do not exist, surely not 'black' ones.
To a novice, the notion of 'painting' (and 'digging') is clear yet how to spot the degree on an ASET imageand their effect on 'desirability' and 'value' are unclear (given that apparently it is not extensive enough to mention on the GIA certificate).

Relying on GIA to downgrade a painted stone is not something I would recomend.

HCA 0.7, Table 56, Crown 34.5, Pavilion 40.6, Depth 60.5; 15.0, 2.5, 42.5
Modeled in DiamCalc classic.


this time I have painted the crown facets severely


And now a little lower gridle facet as well


The effect is to lower both the crown upper girdle facets and the pavilion lower girdle facet angles. This is severe painting.


20 years ago the Eight Star brand were doing this and some people were big fans.

 

[Garry H (Cut Nut)]

ASET shows Light Performance. H&A is another thing - a matter of Optical Precision - which @Garry H (Cut Nut) calls symmetry above.
An ASET image doesn't need to show perfect Optical Precision (arrows-patterns) for the diamond to be bright and earn AGS 0.

I would like to clarify my statement as to John's earlier comment:
John is inaccurate in separating optical symmetry from actual symmetry.
In my view symmetry is symmetry. Optical symmetry, as shown by H&A's Ideal-Scope and ASET, is the easiest way to demonstrate good or bad symmetry - using optical tools. But the industry has screwed up what symmetry is or should be - like so many things - it is as a result of historical methods.

First a cutter must decide to produce a symmetrical diamond. And Labs set their standards for symmetry. Some of those standards are old and pretty useless - facet meet points for example - before diamonds were scanned by non contact devices that build very accurate 3D models - the standards were human visual based.
Putting those old standards into new high tech devices stretched the capacity of geochemists (which is what advanced gemmologists are).
So John naturally refers to optical symmetry, and so do I. But when I use the term I am referring to the same thing from a purist and more physicist point of view.

For example this GIA Good symmetry stone has very good optical symmetry - or could I say near perfect symmetry?
http://www.gemology.ru/cut/english/symmetry/6.htm
From 2003. The table was tilted but had little or no impact on the diamonds excellent performance:


This realization was part of the reason Sergey and I lodged this patent:

US7259839B2 - Method and apparatus for examining a diamond - Google Patents

Prior methods of measuring diamond proportions in order to construct a complete model, such as a three dimensional virtual wire-frame model, of a diamond have been found to be inadequate. In particular, there has been no commercially available, automated and objective method for measuring the...

patents.google.com

Which after more than a decade led to the development of this instrument (and it's partner for crown facets:

Grading & Branding | HP Pavilion Reflect

www.lexus-com.com

Now when we talk about 'symmetry' diamond cutters can easily achieve fantastic symmetry almost all the time. but since the gate keepers allow this - why not get really accurate so you can squeeze more weight out and get GIA XXX:


So sadly, Symmetry is a misused word, but as an occasional purist I like to use it in the correct context.

 

[LSG]

Very instructive.

Thank you Garry Holloway for the DiamCalc images and your tilt adjustment example, very clear (for now) !

On the third ASET image, it is apparently not a major issue that the contrast portions are not the same tone/intensity (perhaps due to the likely table tilt).
The adjacent contrast areas, particularly to the arrow heads are apparently not problematic either, as long as we are not looking for a Hearts and Arrows (which we are not).

Our top criteria are brilliance and fire (and 'dynamic scintillation').

In the rest of this post are observations from a novice buyer, which once again pleads for an article and education as suggested by John Pollard above:

Aside from the boutiques selling Hearts and Arrows, the 'trade' doesn't have (readily on hand ?) ASET or Ideal-Scope images on many diamonds of interest to us.
If no image (which has been the case two out of three times on Ideal-rated stones, not dissimilar to the above), we pass.

One reason why ASET images are not more widely provided by 'the trade' might be that they are hard to interpret by 'novice' buyers and thus might make people reluctant to buy (?).
It might also be difficult to easily take consistent images (I read that even one H&A boutique had issues, that are now resolved, taking quite some trial, error, time and thus investment to resolve).

The Ideal-Scope gives less information than the ASET image, yet is it easier to take consistent images and to interpret an image by a 'novice' ?
It would seem so.
We were only rarely able to get Ideal-Scope images on a diamond.

I am not sure what musicloveranthony means by "LSG should be a trade member";
I am not.
I do have a passion, a gemologist degree that was left behind 25 years ago, and with three children and three grandchildren buying occasions seem to be increasing.
I also am curious and like to know what I'm buying.

Best regards,

LSG Laure

 

[John Pollard]

In my view symmetry is symmetry. Optical symmetry, as shown by H&A's Ideal-Scope and ASET, is the easiest way to demonstrate good or bad symmetry - using optical tools.

@Garry H (Cut Nut) - to understand my position you'll need to take off your gemmo hat, and put on your teaching cap.

The word symmetry appears on every diamond report, along with a grade. Newbies skimming your posts could presume whatever the great "Cut Nut" is describing - using the same word - is what's being evaluated by the lab. Simply put, as an educator, I believe causal use of the word symmetry could lead a casual reader to conclude that any diamond with GIA "Excellent" symmetry has perfect Hearts & Arrows.

I added an anchor here, which jumps to a relevant illustration.

Hearts and Arrows Diamonds: Everything You Need To Know

Find out why a Hearts and Arrows diamond is considered to be so special and why they cost more. Discover the benefits here.

www.pricescope.com

 

[Karl_K]

I agree with John because the labs have given one meaning to a word, using it for another related but not the same thing without clarification is just making things more complicated and harder to teach.

 

[Garry H (Cut Nut)]

@Garry H (Cut Nut) - to understand my position you'll need to take off your gemmo hat, and put on your teaching cap.

The word symmetry appears on every diamond report, along with a grade. Newbies skimming your posts could presume whatever the great "Cut Nut" is describing - using the same word - is what's being evaluated by the lab. Simply put, as an educator, I believe causal use of the word symmetry could lead a casual reader to conclude that any diamond with GIA "Excellent" symmetry has perfect Hearts & Arrows.

I added an anchor here, which jumps to a relevant illustration.

Hearts and Arrows Diamonds: Everything You Need To Know

Find out why a Hearts and Arrows diamond is considered to be so special and why they cost more. Discover the benefits here.

www.pricescope.com

You are of course correct - SYMMETRY as labs grade it, is NOT OPTICAL SYMMETRY which is far more important when considering the visual aspects of diamonds.
For a big part of your life a teacher of young people in schools - and for the past 2 decades have become a world leading teacher about diamonds. So I deserve a spanking.

I dived on the opportunity here to take the opportunity to teach advanced folk in these here parts. LSG is obviously up to the task based on his first post:

(PS John can you please teach me how to add multiple quotes as I am old and dumb)
As usual your anchored ed-op is perfect - but there is an implication that one of those shocking H&A's images is an AGS 0 - worth clarification?

 

[John Pollard]

You are of course correct - SYMMETRY as labs grade it, is NOT OPTICAL SYMMETRY which is far more important when considering the visual aspects of diamonds.
For a big part of your life a teacher of young people in schools - and for the past 2 decades have become a world leading teacher about diamonds. So I deserve a spanking.

I dived on the opportunity here to take the opportunity to teach advanced folk in these here parts. LSG is obviously up to the task based on his first post:

Thanks and yes. However - like a diamond - a PriceScope thread is forever.

My concern isn't the here and now where you're riffing with an advanced poster like @LSG . It’s for the many newbie shoppers who scan down your threads a million times in the forever future - drawing bad conclusions about what their grading report implies bc you use that word (cue Inigo Montoya).

This is why I use “optical precision” - so no consumer, now or later, will ever confuse my comments on that topic with what GIA 3EX “symmetry" means.

(PS John can you please teach me how to add multiple quotes as I am old and dumb)
As usual your anchored ed-op is perfect - but there is an implication that one of those shocking H&A's images is an AGS 0 - worth clarification?

You're neither old nor dumb, and you know it, haha. For multi-quote I toggle BB code and edit html manually. And yes, the image you refer to should indeed be part of the EDU page @LSG has requested covering AGS0's that have good performance, but are not H&A.

 

[Garry H (Cut Nut)]

Thanks and yes. However - like a diamond - a PriceScope thread is forever.

My concern isn't the here and now where you're riffing with an advanced poster like @LSG . It’s for the many newbie shoppers who scan down your threads a million times in the forever future - drawing bad conclusions about what their grading report implies bc you use that word (cue Inigo Montoya).

Yes, I hope I would not dive in so deep on the average newbie thread.
Sometimes I am a bit brief but bump a thread hoping newbies will get explanations from different prosumers with slightly different takes - I think overall we do that pretty well Team PS.
But when some one mentions painting and digging in their first post - then it's a great opp to dig deeper (pun).

 

[LSG]

Again thank you all, it was worth it for myself and I am sure a large percentage of your community; if not their first purchase, hopefully later ones.

As stated, I believe ASET and Ideal-Scope images aren't usually made available to customers as wholesalers are afraid they will not be read properly.

And indeed, retail customery often don't know how to read them well if they are not near-perfect Hearts and Arrows.

Also, I used the words mentioned above as when one asks the vendor after receiving an image and making 'novice' comments, the salesperson says 'yes' you are right ; "Some minor light leakage, minor painting and digging, minor tilt... minor lack of symmetry."
"Don't worry, buy on the GIA or ASG specifications, no one will notice anyway, ... you won't find better at that price"...
OK...

Thus John Pollard, an article oriented to mid-level plus retail customers would help customers make better decisions and may encourage wider use of ASET and Ideal-Scope image usage generally.

Best regards,

LSG Laure

 

[Garry H (Cut Nut)]

As stated, I believe ASET and Ideal-Scope images aren't usually made available to customers as wholesalers are afraid they will not be read properly.
And indeed, retail customery often don't know how to read them well if they are not near-perfect Hearts and Arrows.

Also, I used the words mentioned above as when one asks the vendor after receiving an image and making 'novice' comments, the salesperson says 'yes' you are right ; "Some minor light leakage, minor painting and digging, minor tilt... minor lack of symmetry."
"Don't worry, buy on the GIA or ASG specifications, no one will notice anyway, ... you won't find better at that price"...
OK...

Thus John Pollard, an article oriented to mid-level plus retail customers would help customers make better decisions and may encourage wider use of ASET and Ideal-Scope image usage generally.

Best regards,

LSG Laure

LSG sadly there are so many factors.
1. most diamonds fail these tools . Even the vast majority of GIA XXX.
2. diamond dealers, in my experience, have little or no interest in technicalities.
3. retail sales people have often worked across various sales positions from shoes, handbag's, real estate etc
Another factor that many employers understand is too much knowledge often kills sales ability. e.g. the watchmaker in the business is the worst tic toc sales person in the business. Who cares about what's inside the case!