Show me examples of good numbers, poor idealscope

[Karl_K]

Spot on 3d optical symmetry in a real cut diamond to a model in DC is impossible there will always be deviations in precision in an actual polished stone not found in the model.

That is true the perfectly cut diamond has never been cut, some are just closer than others.
Which is why I said similar and not exactly.....

 

[pfunk]

Pfunk

You may be concentrating on the wrong facet angles.... I knew a store owner, or owners in a great jewelry store once and the most important of their rules in picking out diamonds was depth to width ratio in a round diamond. If the depth to width ratio is within 2% the brilliance of a diamond will be at it's best. There should be almost NO loss of light refraction. I have since graduated from GIA as a G.G.
Albeit that crown angles play a part, if the depth to width ratio is within 2% the crown angles shouldn't be too far off. It could happen but
it's not likely. You should be able to tell from a GIA report all you need to know. All the percentages and measurements are there.

There is something to crown angles because in the world of diamonds sometimes people will change any angle they have to in order to
retain as much carat weight as possible. All things being equal in the world of diamonds weight seems to set the price if all other aspects are within tolerable limits. However, if they are smart enough to know about depth to width ratio then they should also be aware of the crown angles to a great extent. But if you look at a diamond with 2% depth to width ratio you will notice that it has such great light return that you will notice on other diamonds when it isn't there. Look at several diamonds with ratios that are different then look at one within the 2% rule and you will notice that you cannot even see into a diamond with that 2% rule all you can see is light return, it's almost difficult to see the pavilion facets because of light return. When the angles are more than 2% you can see INTO the diamond. Anytime you can see into a diamond it is probably not that great. It should be difficult to see the pavilion facets on a diamond that is within that rule. There are other rules governing other shapes as well but the rule will remain the same. On a beautifully cut diamond of any shape you should not be able to see the pavilion facets too well because of the light coming out of the table and crown facets.
The exception to this would be an emerald cut diamond. I am writing about multi faceted pavilion diamonds. If the proportions are correct on any shape and the light is being returned then it is probably well cut.
Also, if the cut if very good or better you should see the heart and arrows in a round diamond, or in the scopes of any type. Providing that the cut is very good and the depth to width ratio is with the 2% rule.

I am a Certified Graduate Gemologist from GIA. Class of 08

Forgive me for being new to all of this, but I don't understand what "deth to width ratio" you are talking about or how it is measured as a percentage. A ratio is a whole number, not a percentage. Can you describe how exactly you calculate this number from the measurents on a GIA report?

Also, when you say you should not be able to see into the diamond and see the pavilion facets, do you mean when viewing perpendicular to the table? Even then I am quite sure I can see the pavilion facets (arrows) and I can especially see them when on a tilt as they throw back bright reflections of light.

 

[Paul-Antwerp]

You may be new to this, pfunk, but I am in this over 25 years, and I do not understand a thing Jamiegems is claiming.

None of his claims make any sense, when considering physics.

Live long,

 

[pfunk]

You may be new to this, pfunk, but I am in this over 25 years, and I do not understand a thing Jamiegems is claiming.

None of his claims make any sense, when considering physics.

Live long,

Glad i'm not alone. I was really scratching my head.

 

[John P]

Thanks John. I don't think anyone will disagree with you there, but the question still remains. For those who work with volumes of diamonds how often does an exception to the rule present?

Texas Leaguer beat me to it.

[Kobi, I'm sure John will have thoughts on this, but it does go back to what Paul mentioned. It depends on your definition of poor. I will say this, it is very common for GIA triple ex, even those with good numbers, to have poor optical precision. Is the diamond still attractive? Yes. Is it's full potential diminished significantly. Yes. (I tried to make that case above) Does that make it a poor cut? Maybe not for some folks, but for others it's a deal breaker.

Here's the quote he mentioned.

For me personally, whatever GIA-EX I see, regardless of supposed H&A or nice Idealscope, I see unnecessary weight-retention ranging from 1% to 15% and under-achievement in beauty. But that is personal. I see consumers appreciating the differences in beauty, and considering the money well-spent and actually a money-saver. I see other consumers clearly observing the differences in beauty, but not willing to give up an illusive carat weight (or color or clarity), thus having a completely different definition of 'good enough'. I see many consumers simply dismissing the differences in beauty, in fact not wanting to try and see it. They have a definition they prefer not to challenge, and that is their prerogative.

But realizing that your questions hinge on the definition of poor or good, me having an extremely strict definition of good does not make me the correct person to answer your follow-up-questions. I still have not seen a diamond from elsewhere, that I did not consider improvable. From that perspective, I cannot answer your questions.

Some e-places sell diamonds sight-unseen; happy to drop-ship them with no exam or oversight whatsoever.
Some e-places sell diamonds only after the expense of bringing in, 100% inspection/analyses and a demonstrative suite of images.

Neither model is "wrong" but there's an undeniably greater possibility of the buyer getting something off-color, off-clarity, off-cut or brown-green-milky from the first model. Thus my view on images, in the spirit of my prior post, is that erring on the safe side doesn't hurt anyone - and protects everyone.

 

[Texas Leaguer]

Jamiegems,
I see that most of you posts so far contain advice about this 2% rule. I'm sure you have other consumers in other threads wondering about this calculation so it would be a good idea to explain it in detail.

A couple of other things you might want to know as someone new to this forum. The rules for trademembers are a little different than for consumers. You can read them here:
https://www.pricescope.com/content/forum-policies
One of the rules is that you are supposed to have your name in your signature file. (you also should check with GIA for the proper use of your credential as I don't believe they allow the term "Certified" Graduate Gemologist.)

And I would encourage you to spend some time upfront reading many different threads and accessing some of the knowledge base materials and articles here on pricescope. There are many things discussed here that are not taught by GIA. For instance, because GIA considers all GIA Excellent cuts to be equally top notch, they don't go heavily into optical precision (3D alignment, sometimes also refered to as optical symmetry) or the tools used by many to judge it. You should also be aware of the American Gem Society Laboratories and the work they have done on light performance based cut grading. It is something discussed here frequently.

Moreover, take your time. Walk before you run. You will learn alot in the process.

 

[John P]

I appreciate that many, likely a majority on PS, want the most precisely cut diamond possible. That is completely, perfectly acceptable to me. I also don't mind if people want D color, or flawless clarity.

I feel that way too, if the consumer is making an educated decision. In fact the bolded part highlights a huge challenge with cut, especially on the internet.

We don't have the specificity in cut that we do in color and clarity. "GIA D-Flawless" is very specific. But "GIA D Flawless 3EX" introduces so many variables. That could be an icy firecracker with dynamic qualities, or an icy made-the-weight steep-deep with angles creating darkness anyone can see away from the showroom. D color is specific. EX is not. Just imagine if all diamonds, DEFGHIJ, were given the same color grade. Let's call it "Neat" color. People would come to PS and say what do you think of a 1.00ct "Neat" VS2 and we'd need to say "Neat" could be anywhere from icy to warm. We need more info.

For more cut specificity IS and ASET are useful. Applying the "Neat" metaphor we can reject some levels for problems in static brightness, pattern, etc. But there is a limit, since it's a single static view, and only showing brightness, contrast and leakage. In live viewing there are further observable nuances. Some predictable. Some not. As it relates to this thread I agree that strong IS/ASET can bring many to a level they're comfortable with. Yet in the spirit of your first comment, which I bolded, some people demonstrably want this, even in the area of cut.

The other problem for me is that all of the appeal for precision cut diamonds is being couched in scientific terms, and yet when we ask how and in what ways this extra drop of precision will make a difference in real life, the answer is that it's too hard to articulate.

I don't find it hard to articulate. I simply don't draw those conclusions from numbers or images - for all the reasons in this thread. Pushing it on the forum would also be promotional. My mission since 2004 has been consumer education, empowering confident diamond buying on the internet and supporting great service by local jewelers, in-line with the spirit of Pricescope (which I value immensely). That doesn't mean I can't articulate more on the topic - I do for manufacturers, labs and jewelers spanning three continents.

It sounds almost like this sales pitch: "Buy this glass of water because it has 3 extra drops that, over time, will make you more hydrated"--technically yes, but in such a subtle way that you literally will not notice. Will the diamond be brighter, or more dynamically interesting? The answer is technically yes, but in such a subtle way that you almost definitely wouldn't notice.

It is subtle, yet people do notice. That's not in question. Consumers have documented that for years on this site. It happens in showrooms away from Pricescope every day. Some folks see it immediately. Others acknowledge it but prioritize something else. Some don't see it. None of them are wrong, or lying, they're reporting their individual experiences. People are different. Ideally pros should empower educated decisions on all fronts including shape, carat-color-clarity and pedagogy covering the total range and motivations of modern cut.

Can you imagine if a jeweler in every city carried an inventory of standard RBs along with a true dedicated superideal, an optimized cushion, a superior princess and Octavia. What an awesome shopping experience. Come see a range of graduated diamonds blanketing the gamut of "what is possible" in terms of man's modern cutting abilities. That's not all. Imagine if they let people "check out" two or three like a diamond library. Travel through your world of lighting scenarios and observe them. Learn the nuances and gain perception of the different flavors. Do you like the J or prefer the G? Ah, the crystal can be seen in your office. How did the cushion's broadfire compare to that MRB's scintillation in the sun? In your bathroom? In your favorite restaurant?

That panacea of diamond education empowerment would be cool for the enthusiasts who would take advantage (any volunteers?). Not everyone would bother with it (Dude, I just want a rock), but that's cool too. By the way, minus the checkout situation I know a few stores here and there stocking an inventory similar to the described - one of them contributes on PS. They're serving their showroom clients at a level few achieve.

 

[KobiD]

I found and watched this video by GOG (but have not listened to the audio). https://www.youtube.com/watch?v=xwStaSq1W4Q

It would be nice to have more information available in regards to the actual proportions of the stones, as well as an IS and ASET to complete the data.

From the video alone, its evident that there is a difference between the two stones, but very subtle. Here is another comparing Superior vs Premium. Again, addition info on the proprtions would allow us to further evaluate. https://www.youtube.com/watch?v=uxVfKUJsRZY

 

[John P]

Also showing customers the differences between "Near Tolk","Tolk", "Superideal H&A" in their size and color preference is often not economically viable as well. Availability & Price are much more important than the subtle and often imperceptible differences between them.

For those who perceive, it's a matter of balance. The difference seen is usually about scintillation. With proper availability, many choose to drop a color grade to keep that look and stay in budget. It certainly helps that color pre-conceptions are easy to overcome in showroom situations.

CA/PA combination dwarves many other considerations when considering fine makes already within the GIA XXX range. The GIA system works for the industry in general and is the most widely accepted cut grading we have. Sure their are outliers, false positives, and some of the GIA range(especially the borders) are visually less appealing than the zenith but most GIA XXX are well cut diamonds to all but the most fanatical who have likely already bought into the hype and marketing of the "Superideals". As you go from one level to the next within the middle of the GIA XXX range the detectable differences with the human eye become less obvious until they are not noticeable without magnification.

The answers you have gotten from trademembers and pricescope faithful who sell, support, and market "Superior Cut" and "Superideals" and the consumers who self validate their own purchases from these very vendors should be taken into proper perspective. It is very much still a niche taste and a "Mind Clean" aspect. It is also a high concentration of the sponsoring and participating trade here who focus on this section of the market.

RE "consumers who self validate:" You may be surprised at how perceptive some folks are. As it relates to Pricescope I hope you'll come to the JCK Get Together. You'll get organic perspective from very experienced enthusiasts on a wide range of topics. These people aren't delusional. Observant? Yes. In many areas. It's a diverse group that doesn't need "self validation."

Now step away from Pricescope and you have tens of thousands (100,000s?) of Hearts On Fire owners who did comparisons in showrooms. They viewed zenith-XXX, near-Tolk, etc., and chose the HOF proposition, despite a greater markup. Moreover, last year HOF was purchased by Chao Tai Fook, the world's largest jewelry company. If CTF could have replicated the HOF look with "close" or zenith-XXX standards they would have done so. They could not. Such dedicated productions cost more in time, tools and commitment to a vision, and are extremely limited in supply.

As for technical teeth, I am proud to be a consultant for some major labs and leading cut-researchers. Without violating any NDAs I can say studies in more than one place agree that increasing cut-precision increases virtual facet size. In common weights this can lead to more perceived fire, more intense/pure spectral colors and more "on-off" crispness to the scintillation. In layman's terms, the more fine-tuning of the diamond's mirrors, the more places it will provide maximized performance. Unlike a fast, clinical judgment of color or clarity, this is an area which involves nuance and perception over time, through all illumination scenarios. We don't have a metric which reflects all of this yet. But we continue to try and understand it.

"Self validation" doesn't stimulate cut evolution. Perception does. Perception sustained Lazare Kaplan's application of cousin Marcel's efforts. Perception sustained Tiffany's standards through the 1900s. It sustained development of the old GIA cut-categories. It sustained precision-cutting in 80s-90s Japan. It sustained AGSL's 1996 proportions system and their improved 2005 performance grade. It sustained the development of DC cut-improvement software. It sustained GIA's introduction of cut grading for rounds in 2006. Now it sustains continuing studies beyond our existing metrics...

10 years ago the world was full of jewelers screaming "You only need 60T 60D! Don't look farther!"...(curse those superideal guys)
Today it's full of jewelers screaming "You only need GIA EX! Don't look farther!"...(curse those superideal guys)
Even some on cut-focused PS say "You only need ASET! Don't look farther!"...(curse those superideal guys)

Meanwhile, there are diamond cutters who target a higher proposition on principal. It's undeniably a harder path, yet some dedicate their careers to it. Ironically I find them to be the ones saying: "Experience *everything* and choose with your eyes wide open."

(Look teobdl, you got me to articulate)

 

[pfunk]

Thanks for sharing those Kobi! Very helpful to show some of the difference, though it would be, as you stated, even more useful if we had the numbers and reflector images. Here is another video that shows the differences between a range of GIA grades and a superideal and DOES include reflector images. I wish the GIA excellent that was used in this video was one that didn't have obvious light leakage everywhere under the table, but it is still very helpful. The differences, while certainly present, are subtle. I would love to see a video like this comparing ideal proportioned GIA excellents (not cut to the edge of excellent) vs. ags 000 hearts and arrows.

https://m.youtube.com/watch?v=cp94DI3xTA0

 

[KobiD]

OK! This is getting closer to what I'd like to see. Some very good compairsons, however with one diamond having a rather shallow CA.

https://www.youtube.com/watch?v=Lb0oudyrQPo
https://www.youtube.com/watch?v=c4zo7iYUwGQ

Very good educational video, multiple light sources, cert data, IS/ASET, HCA score. Again, I haven't listened to the audio. Just gauging purely from a visual aspect.

 

[MelisendeDiamonds]

Thus my view on images, in the spirit of my prior post, is that erring on the safe side doesn't hurt anyone - and protects everyone.

It actually does hurt those shopping on a budget particularly at certain price points. Paying for something you cannot see and sacrificing size or color to get "mind clean cut" is not going be the best value proposition for a fair number of consumers.

I am sure you are familiar with limited carat range for "Superideals", rarely less than 0.4 carats or over 3 carats.

I suspect the facets are too small to appreciate the differences at small carat weights and price premium leads to reduced saleability at the higher carat weights making the risk of tieing up capital in such expensive stones too great.

 

[pfunk]

Great videos Kobi. Thanks for sharing. I do find it interesting though what they are choosing as "ideal" diamonds for comparison. The 32.5 crown angle is definitely not what I consider ideal and I think it was more obviously different from the superideal. The 33.5 crown angle was more similar to the super ideal in my opinion and was harder to distinguish, though you could still see the differences. They also seem to think that a lower HCA indicates a theoretically better diamond, though that isnt the case when both score under 2.

 

[Texas Leaguer]

I disagree with that in the real world I have seen diamonds that were fics, bics, steep-deeps, shallow-shallow. and oec with high levels of 3d optical symmetry some with images that would be called h&a some not.

>>> When considering hearts images in the Modern Round Brilliant, and Ideal Hearts and Arrows images, one must be reasonably close to Tolk proportions to qualify by definition (see HRD standards). If you relax your standards to "close" to Ideal hearts and don't define what is close than the term is just a marketing one and my statement has little meaning.

I wouldn't even include an OEC, or most fancy shapes by definition as having a pattern that qualifies as Ideal hearts and arrows in an MRB. This discussion and my comments focus on the Modern Round Brilliant and not fancy shapes as that has not been the focus of this thread.

My point was because a diamond is not a tic does not mean it isn't cut with a high level of 3d optical symmetry just like it being a tic does not mean it was.
Further:
Heart and arrows is a marketing term for the images that some combos of RB show under the viewer when they have high levels of 3d optical symmetry.
Further:
An RB can have a high level of optical symmetry and not be h&a.
For example I have seen pavilion views in a heart viewer similar to this virtual model:

I have seen diamonds with similar views and it shows spot on 3d optical symmetry but not h&a.

This is an interesting example of a GIA Triple Ex we brought in for a customer a while back which I think helps illustrate Karl's point. I have cropped out the cert number to respect confidentiality.

 

[superfluous]

I disagree with that in the real world I have seen diamonds that were fics, bics, steep-deeps, shallow-shallow. and oec with high levels of 3d optical symmetry some with images that would be called h&a some not.

>>> When considering hearts images in the Modern Round Brilliant, and Ideal Hearts and Arrows images, one must be reasonably close to Tolk proportions to qualify by definition (see HRD standards). If you relax your standards to "close" to Ideal hearts and don't define what is close than the term is just a marketing one and my statement has little meaning.

I wouldn't even include an OEC, or most fancy shapes by definition as having a pattern that qualifies as Ideal hearts and arrows in an MRB. This discussion and my comments focus on the Modern Round Brilliant and not fancy shapes as that has not been the focus of this thread.

My point was because a diamond is not a tic does not mean it isn't cut with a high level of 3d optical symmetry just like it being a tic does not mean it was.
Further:
Heart and arrows is a marketing term for the images that some combos of RB show under the viewer when they have high levels of 3d optical symmetry.
Further:
An RB can have a high level of optical symmetry and not be h&a.
For example I have seen pavilion views in a heart viewer similar to this virtual model:

I have seen diamonds with similar views and it shows spot on 3d optical symmetry but not h&a.

This is an interesting example of a GIA Triple Ex we brought in for a customer a while back which I think helps illustrate Karl's point. I have cropped out the cert number to respect confidentiality.

This is interesting. Do you have any examples of poor AGS000?

 

[pfunk]

I disagree with that in the real world I have seen diamonds that were fics, bics, steep-deeps, shallow-shallow. and oec with high levels of 3d optical symmetry some with images that would be called h&a some not.

>>> When considering hearts images in the Modern Round Brilliant, and Ideal Hearts and Arrows images, one must be reasonably close to Tolk proportions to qualify by definition (see HRD standards). If you relax your standards to "close" to Ideal hearts and don't define what is close than the term is just a marketing one and my statement has little meaning.

I wouldn't even include an OEC, or most fancy shapes by definition as having a pattern that qualifies as Ideal hearts and arrows in an MRB. This discussion and my comments focus on the Modern Round Brilliant and not fancy shapes as that has not been the focus of this thread.

My point was because a diamond is not a tic does not mean it isn't cut with a high level of 3d optical symmetry just like it being a tic does not mean it was.
Further:
Heart and arrows is a marketing term for the images that some combos of RB show under the viewer when they have high levels of 3d optical symmetry.
Further:
An RB can have a high level of optical symmetry and not be h&a.
For example I have seen pavilion views in a heart viewer similar to this virtual model:

I have seen diamonds with similar views and it shows spot on 3d optical symmetry but not h&a.

This is an interesting example of a GIA Triple Ex we brought in for a customer a while back which I think helps illustrate Karl's point. I have cropped out the cert number to respect confidentiality.

TL, are you saying this diamond has what some would consider to be "near hearts and arrows"? This diamond fails miserably on the HCA with that deep pavilion. It is not surprising it has a large amount of leakage. Just trying to see what the point is here? Forgive me if I am missing something obvious. If you are saying this diamond has near hearts and arrows but still has a lot of leakage, I am not surprised. If it is that a diamond with "near tolk" numbers can have bad leakage, that is no surprise here as this isn't near tolk with that deep pavilion and a little larger table too.

 

[KobiD]

I believe TLs post was to demonstrate that a stone can have a high level of optical symmetry, but still perform badly based on proportions. It does/doesn't show H&A depending on your definition. As for the proportions of that stone, most would agree that they are stretched beyond the edge of ideal and into the outlying areas of the GIA Ex Ex Ex range, and the associated leakage is no surprise.

Sticking to the original post though, I'd really like to see some examples of stones in the range of CA 34-35, and PA 40.6-40.9 that lack some optical symmetry but still perform well. Even more so, I'd like to see if any in those ranges are able to show leakage close to what was displayed above.

 

[Texas Leaguer]

I believe TLs post was to demonstrate that a stone can have a high level of optical symmetry, but still perform badly based on proportions. It does/doesn't show H&A depending on your definition. As for the proportions of that stone, most would agree that they are stretched beyond the edge of ideal and into the outlying areas of the GIA Ex Ex Ex range, and the associated leakage is no surprise.

Sticking to the original post though, I'd really like to see some examples of stones in the range of CA 34-35, and PA 40.6-40.9 that lack some optical symmetry but still perform well. Even more so, I'd like to see if any in those ranges are able to show leakage close to what was displayed above.

Yes, I was just picking up on Karl's point that stones are sometimes cut with high precision yet still fail to address significant performance flaws.

 

[pfunk]

I believe TLs post was to demonstrate that a stone can have a high level of optical symmetry, but still perform badly based on proportions. It does/doesn't show H&A depending on your definition. As for the proportions of that stone, most would agree that they are stretched beyond the edge of ideal and into the outlying areas of the GIA Ex Ex Ex range, and the associated leakage is no surprise.

Sticking to the original post though, I'd really like to see some examples of stones in the range of CA 34-35, and PA 40.6-40.9 that lack some optical symmetry but still perform well. Even more so, I'd like to see if any in those ranges are able to show leakage close to what was displayed above.

Yes, I was just picking up on Karl's point that stones are sometimes cut with high precision yet still fail to address significant performance flaws.

Thanks for clarifying. I am following you now. I just didnt know from looking at thos particular images that the stone was cut with precise optical symmetry.

As Kobi stated, I am still interested in the original question. How often are you going to see any truly problematic amount of leakage on an IS image if you stick to more strict ideal measurements. Is the IS mostly used, in those cases, to find a rare under performer? If so, how rare is it? Or is it used to nit pick between diamonds that perform well but have small differences. And in real life, how many people will see those differences. Meaning, if you gave them the two diamonds and didnt tell them which was which, how likely are they to pick the one that has the slightly more perfect IS?

 

[Texas Leaguer]

I believe TLs post was to demonstrate that a stone can have a high level of optical symmetry, but still perform badly based on proportions. It does/doesn't show H&A depending on your definition. As for the proportions of that stone, most would agree that they are stretched beyond the edge of ideal and into the outlying areas of the GIA Ex Ex Ex range, and the associated leakage is no surprise.

Sticking to the original post though, I'd really like to see some examples of stones in the range of CA 34-35, and PA 40.6-40.9 that lack some optical symmetry but still perform well. Even more so, I'd like to see if any in those ranges are able to show leakage close to what was displayed above.

Yes, I was just picking up on Karl's point that stones are sometimes cut with high precision yet still fail to address significant performance flaws.

Thanks for clarifying. I am following you now. I just didnt know from looking at thos particular images that the stone was cut with precise optical symmetry.

As Kobi stated, I am still interested in the original question. How often are you going to see any truly problematic amount of leakage on an IS image if you stick to more strict ideal measurements. Is the IS mostly used, in those cases, to find a rare under performer? If so, how rare is it? Or is it used to nit pick between diamonds that perform well but have small differences. And in real life, how many people will see those differences. Meaning, if you gave them the two diamonds and didnt tell them which was which, how likely are they to pick the one that has the slightly more perfect IS?

I think the basic premise postulated by the thread is sound. If you stick with GIA triple ex in the sweet spot of ideal proportions, with no complicating factors, you have a high probability of getting a nice performing diamond that most people will find perfectly suitable. If you are looking for top quality craftsmanship and ultimate performance you need additional information to asses factors such as optical precision.

 

[Serg]

I believe TLs post was to demonstrate that a stone can have a high level of optical symmetry, but still perform badly based on proportions. It does/doesn't show H&A depending on your definition. As for the proportions of that stone, most would agree that they are stretched beyond the edge of ideal and into the outlying areas of the GIA Ex Ex Ex range, and the associated leakage is no surprise.

Sticking to the original post though, I'd really like to see some examples of stones in the range of CA 34-35, and PA 40.6-40.9 that lack some optical symmetry but still perform well. Even more so, I'd like to see if any in those ranges are able to show leakage close to what was displayed above.

Yes, I was just picking up on Karl's point that stones are sometimes cut with high precision yet still fail to address significant performance flaws.

Bryan,did you check this diamond yourself, by naked eye in consumer light environment ? If yes, can you please compare Fire, Brilliance with any H&A + AGSO with similar mass?

 

[Texas Leaguer]

I believe TLs post was to demonstrate that a stone can have a high level of optical symmetry, but still perform badly based on proportions. It does/doesn't show H&A depending on your definition. As for the proportions of that stone, most would agree that they are stretched beyond the edge of ideal and into the outlying areas of the GIA Ex Ex Ex range, and the associated leakage is no surprise.

Sticking to the original post though, I'd really like to see some examples of stones in the range of CA 34-35, and PA 40.6-40.9 that lack some optical symmetry but still perform well. Even more so, I'd like to see if any in those ranges are able to show leakage close to what was displayed above.

Yes, I was just picking up on Karl's point that stones are sometimes cut with high precision yet still fail to address significant performance flaws.

Bryan,did you check this diamond yourself, by naked eye in consumer light environment ? If yes, can you please compare Fire, Brilliance with any H&A + AGSO with similar mass?

No Serg, it was a stone we brought in at some point in the past for a customer. I don't have it in hand to check it out. I ran across the images and thought it was a real world example of what Karl mentioned, that you can have very good execution in terms of precision and not necessarily be hitting or even targeting ideal parameters.

What is your view of the question(s) posed by this thread?

 

[MelisendeDiamonds]

I believe TLs post was to demonstrate that a stone can have a high level of optical symmetry, but still perform badly based on proportions. It does/doesn't show H&A depending on your definition. As for the proportions of that stone, most would agree that they are stretched beyond the edge of ideal and into the outlying areas of the GIA Ex Ex Ex range, and the associated leakage is no surprise.

Sticking to the original post though, I'd really like to see some examples of stones in the range of CA 34-35, and PA 40.6-40.9 that lack some optical symmetry but still perform well. Even more so, I'd like to see if any in those ranges are able to show leakage close to what was displayed above.

Yes, I was just picking up on Karl's point that stones are sometimes cut with high precision yet still fail to address significant performance flaws.

Did you prove that that stone was cut with high precision? If so how? Hearts image?
Sorry I don't see anything being provided with those images. As has been stated many times ASET and Idealscope do not have the contrast ability to infer precision. Moreseo a photograph is rarely a good predictor of precision and that plain photograph does not make that diamond even close to perfect symmetry(could be the lighting).

 

[Serg]

OK! This is getting closer to what I'd like to see. Some very good compairsons, however with one diamond having a rather shallow CA.

https://www.youtube.com/watch?v=Lb0oudyrQPo
https://www.youtube.com/watch?v=c4zo7iYUwGQ

Very good educational video, multiple light sources, cert data, IS/ASET, HCA score. Again, I haven't listened to the audio. Just gauging purely from a visual aspect.

I suppose that right diamond in first movie has dirty pavilion. is anybody have similar opinion?

How was symmetrical the light environment in these movies?

 

[Serg]

I believe TLs post was to demonstrate that a stone can have a high level of optical symmetry, but still perform badly based on proportions. It does/doesn't show H&A depending on your definition. As for the proportions of that stone, most would agree that they are stretched beyond the edge of ideal and into the outlying areas of the GIA Ex Ex Ex range, and the associated leakage is no surprise.

Sticking to the original post though, I'd really like to see some examples of stones in the range of CA 34-35, and PA 40.6-40.9 that lack some optical symmetry but still perform well. Even more so, I'd like to see if any in those ranges are able to show leakage close to what was displayed above.

Yes, I was just picking up on Karl's point that stones are sometimes cut with high precision yet still fail to address significant performance flaws.

Bryan,did you check this diamond yourself, by naked eye in consumer light environment ? If yes, can you please compare Fire, Brilliance with any H&A + AGSO with similar mass?

No Serg, it was a stone we brought in at some point in the past for a customer. I don't have it in hand to check it out. I ran across the images and thought it was a real world example of what Karl mentioned, that you can have very good execution in terms of precision and not necessarily be hitting or even targeting ideal parameters.

What is your view of the question(s) posed by this thread?

Bryan,
Can you specify the question? I saw a lot of Questions and "Questions" in this thread. I am not sure Which issue is main now in the thread.

 

[Texas Leaguer]

I believe TLs post was to demonstrate that a stone can have a high level of optical symmetry, but still perform badly based on proportions. It does/doesn't show H&A depending on your definition. As for the proportions of that stone, most would agree that they are stretched beyond the edge of ideal and into the outlying areas of the GIA Ex Ex Ex range, and the associated leakage is no surprise.

Sticking to the original post though, I'd really like to see some examples of stones in the range of CA 34-35, and PA 40.6-40.9 that lack some optical symmetry but still perform well. Even more so, I'd like to see if any in those ranges are able to show leakage close to what was displayed above.

Yes, I was just picking up on Karl's point that stones are sometimes cut with high precision yet still fail to address significant performance flaws.

Did you prove that that stone was cut with high precision? If so how? Hearts image?
Sorry I don't see anything being provided with those images. As has been stated many times ASET and Idealscope do not have the contrast ability to infer precision. Moreseo a photograph is rarely a good predictor of precision and that plain photograph does not make that diamond even close to perfect symmetry(could be the lighting).

Sorry, I meant to include the hearts image in the original post. Pretty high precision though not perfect.

 

[Texas Leaguer]

I believe TLs post was to demonstrate that a stone can have a high level of optical symmetry, but still perform badly based on proportions. It does/doesn't show H&A depending on your definition. As for the proportions of that stone, most would agree that they are stretched beyond the edge of ideal and into the outlying areas of the GIA Ex Ex Ex range, and the associated leakage is no surprise.

Sticking to the original post though, I'd really like to see some examples of stones in the range of CA 34-35, and PA 40.6-40.9 that lack some optical symmetry but still perform well. Even more so, I'd like to see if any in those ranges are able to show leakage close to what was displayed above.

Yes, I was just picking up on Karl's point that stones are sometimes cut with high precision yet still fail to address significant performance flaws.

Bryan,did you check this diamond yourself, by naked eye in consumer light environment ? If yes, can you please compare Fire, Brilliance with any H&A + AGSO with similar mass?

No Serg, it was a stone we brought in at some point in the past for a customer. I don't have it in hand to check it out. I ran across the images and thought it was a real world example of what Karl mentioned, that you can have very good execution in terms of precision and not necessarily be hitting or even targeting ideal parameters.

What is your view of the question(s) posed by this thread?

Bryan,
Can you specify the question? I saw a lot of Questions and "Questions" in this thread. I am not sure Which issue is main now in the thread.

Serg,
I think pfunk and Kobi may still be trying to understand the question as laid out in the opening post of this thread. I have tried to add my perspective, but I know you will likely have a different view. Shall we say a more stereoscopic one?

 

[Serg]

I believe TLs post was to demonstrate that a stone can have a high level of optical symmetry, but still perform badly based on proportions. It does/doesn't show H&A depending on your definition. As for the proportions of that stone, most would agree that they are stretched beyond the edge of ideal and into the outlying areas of the GIA Ex Ex Ex range, and the associated leakage is no surprise.

Sticking to the original post though, I'd really like to see some examples of stones in the range of CA 34-35, and PA 40.6-40.9 that lack some optical symmetry but still perform well. Even more so, I'd like to see if any in those ranges are able to show leakage close to what was displayed above.

Yes, I was just picking up on Karl's point that stones are sometimes cut with high precision yet still fail to address significant performance flaws.

Bryan,did you check this diamond yourself, by naked eye in consumer light environment ? If yes, can you please compare Fire, Brilliance with any H&A + AGSO with similar mass?

No Serg, it was a stone we brought in at some point in the past for a customer. I don't have it in hand to check it out. I ran across the images and thought it was a real world example of what Karl mentioned, that you can have very good execution in terms of precision and not necessarily be hitting or even targeting ideal parameters.

What is your view of the question(s) posed by this thread?

Bryan,
Can you specify the question? I saw a lot of Questions and "Questions" in this thread. I am not sure Which issue is main now in the thread.

Serg,
I think pfunk and Kobi may still be trying to understand the question as laid out in the opening post of this thread. I have tried to add my perspective, but I know you will likely have a different view. Shall we say a more stereoscopic one?

Bryan,

I do not see reason to discuss again and again Limitations of IS, ASET,. and unsupported interpretations about Leakage, Death rings.,..
what is real interesting : the Correct comparison between P40.7/Cr34.5 and P41.6/Cr33.5 as in your example.

Correct comparison is:
1) Consumer light environments( at least one for Fire, other for Brilliancy)
2) Both diamonds are clean, no fluorescence , Clarity IF-VS2, Colour D-H( but same for each diamond, maximum one color grade difference) , same symmetry( similar to normal H&A, or EX,..)
3) Experts, consumers
4) Blind test
5) Questions for voting : which have better Fire? Which is more Bright? Which Have more Brilliance?
Answers: Left, Right, both are Similar.

before tests the participants have to receive introduction : What Fire is. What Brilliancy is.( explained on samples by different Cuts, without any reference to Symmetry , Ideal, AGS, GIA grades,..)

it is reason why I asked You: " Did you see the stone in consumer light environment"
I expect many can be surprised by this test results. Then we can speak much more effective about Stereoscopic vision .
from My side I am agree to sponsor such tests. ( 5000$ for example)

 

[MelisendeDiamonds]

Also showing customers the differences between "Near Tolk","Tolk", "Superideal H&A" in their size and color preference is often not economically viable as well. Availability & Price are much more important than the subtle and often imperceptible differences between them.

For those who perceive, it's a matter of balance. The difference seen is usually about scintillation. With proper availability, many choose to drop a color grade to keep that look and stay in budget. It certainly helps that color pre-conceptions are easy to overcome in showroom situations.

I don't believe the differences in scintillation are great between a "Tolk" and a "Superideal". I have Peter Yantzer's slides from his presentation at the 2010 Infinity Symposium and have discussed this very comparison. The conclusion I drew was that changing the LGFs has a bigger affect on virtual facet size than a slightly higher level of cut precision. If one is really making a comparison of fine nuances it is difficult to show the client an "apple" to an "apple" and changing something like the CA/PA or LGF makes a bigger difference than the slight differences in cut precision do. Once again this is not comparing an "orange" 33.5/41.6 to an "apple" 34.5/40.8 where the differences are greater.

The answers you have gotten from trademembers and pricescope faithful who sell, support, and market "Superior Cut" and "Superideals" and the consumers who self validate their own purchases from these very vendors should be taken into proper perspective. It is very much still a niche taste and a "Mind Clean" aspect. It is also a high concentration of the sponsoring and participating trade here who focus on this section of the market.

These people aren't delusional. Observant? Yes. In many areas. It's a diverse group that doesn't need "self validation."

I have a great deal of respect for the "Prosumers" and regular posters here, I find them passionate and definitely more knowledgeable and observant and at a higher level than most sales staff I have seen. However when it comes to cut research and experience they are often just passing down what trademembers like yourself have taught on the forums or what was posted unchallenged over the years.

When your opinion isn't balanced there is a good chance neither will theirs. You have to admit your postings have changed a bit since your John Quixote days since you officially became trade and started working for Infinity. There is a spin to them now that wasn't present before, it makes sense, you can't bite the hand that feeds you, even a formidable educator like yourself.

Now step away from Pricescope and you have tens of thousands (100,000s?) of Hearts On Fire owners who did comparisons in showrooms. They viewed zenith-XXX, near-Tolk, etc., and chose the HOF proposition, despite a greater markup.

HOF has a good product and great marketing.

I am always skeptical of "unbiased" showroom comparisons done for sales purposes. I am pretty sure they didn't compare their HOF diamonds to an ACA or CBI, that wouldn't have helped them justify their premium now would it?
In addition the chance of them choosing to compare their HOF to a generic GIA XXX with 34.5/40.8 and decent symmetry is pretty remote as well. It is in their best interest to highlight the advantages of their brand as it is in yours.

Moreover, last year HOF was purchased by Chao Tai Fook, the world's largest jewelry company. If CTF could have replicated the HOF look with "close" or zenith-XXX standards they would have done so. They could not. Such dedicated productions cost more in time, tools and commitment to a vision, and are extremely limited in supply.

I am not going to speak for Chao Tai Fook but private equity is another business I am passionate aboute. Acquisitions are usually for the brand and customer base, and valuations are based on Revenue, EBITDA or bottom line multiple or a combination of both. Rarely would an acquisition be for a production process and if it was, the major driver for valuation of that company better involve pretty exclusive and enforceable patents along with unique IP attached to it, these are things I don't believe HOF ever had. They have done so well due to their marketing, not due to an exclusive product or process.

As for technical teeth, I am proud to be a consultant for some major labs and leading cut-researchers. Without violating any NDAs I can say studies in more than one place agree that increasing cut-precision increases virtual facet size.

No argument there but the question is how much, given your unique position you probably have seen more recent research than I have access to. If you have published studies after 2010 - 2011 research I posted above I'd be interested in reading them.

In common weights this can lead to more perceived fire, more intense/pure spectral colors and more "on-off" crispness to the scintillation. In layman's terms, the more fine-tuning of the diamond's mirrors, the more places it will provide maximized performance. Unlike a fast, clinical judgment of color or clarity, this is an area which involves nuance and perception over time, through all illumination scenarios. We don't have a metric which reflects all of this yet. But we continue to try and understand it.

The same story as from 4-5 years ago anything new?

Meanwhile, there are diamond cutters who target a higher proposition on principal. It's undeniably a harder path, yet some dedicate their careers to it. Ironically I find them to be the ones saying: "Experience *everything* and choose with your eyes wide open."

We agree on that definitely, where we disagree is site unseen choosing over the internet when viewing the choice in person prior to purchase between Tolk and Superideal is not readily available, should the advice be Neutral and balanced or should Pricescope (via you, Wink, Paul, Brian) be persistently pushing customers towards the premium cut option at the expense of other valid priorities(size, color, price).

 

[Rockdiamond]

Thus my view on images, in the spirit of my prior post, is that erring on the safe side doesn't hurt anyone - and protects everyone.

It actually does hurt those shopping on a budget particularly at certain price points. Paying for something you cannot see and sacrificing size or color to get "mind clean cut" is not going be the best value proposition for a fair number of consumers.

I am sure you are familiar with limited carat range for "Superideals", rarely less than 0.4 carats or over 3 carats.

I suspect the facets are too small to appreciate the differences at small carat weights and price premium leads to reduced saleability at the higher carat weights making the risk of tieing up capital in such expensive stones too great.

Perfectly put Haroutioun.
Part of the problem with the discussions on this subject, here on PS is the lack of balance between what people re getting, and what they are sacrificing in cut quality.
No one asking is told they are wrong if they decide to get a VS2 versus an Internally Flawless. Or a G versus a D
But any question regarding cut quality takes on a totally different tone.
Cut is king!
Before we discuss this any further, refer to rule #1