Show me examples of good numbers, poor idealscope

[Rockdiamond]

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.

Illustrative pics Bryan!

I think what Serg was implying was that the photo makes the diamond look bad in a way that might actually look good in person.
Kind of like the blue dress/black dress controversy.

 

[MelisendeDiamonds]

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?

Yes I saw that right away, it invalidates the entire comparison.
Also the Diamond dock where these are being compared is less than ideal for simulating customer lighting.

How was symmetrical the light environment in these movies?

In this video probably pretty poor.

The differences shown in this video cannot simply be attributed to a slightly shallower crown and reduced optical symmetry.

 

[pfunk]

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?

Yes I saw that right away, it invalidates the entire comparison.
Also the Diamond dock where these are being compared is less than ideal for simulating customer lighting.

How was symmetrical the light environment in these movies?

In this video probably pretty poor.

The differences shown in this video cannot simply be attributed to a slightly shallower crown and reduced optical symmetry.

This is why I love having the experts around. You pick up on stuff that I (less educated consumer) often overlook. I didn't consider they could have dirtied up the diamond that they wanted to look inferior, and also put it under lighting that would make it appear worse than their branded stone. The video likely has some bias that I didn't even consider but undoubtedly should have.

It would be awesome to see some completely unbiased videos to draw comparisons, as it is nearly impossible for the consumer to go somewhere where they can view these diamonds side by side in an unbiased environment. I'd love to see a diamond cut to the zenith of GIA excellent side by side with the superideal in conditions like Serg mentioned earlier.

 

[MelisendeDiamonds]

I'd love to see a diamond cut to the zenith of GIA excellent side by side with the superideal in conditions like Serg mentioned earlier.

Check Rhino's (GOG) Youtube or Vimeo videos, especially those where he takes the diamonds outside of the diamond dock by the window. If anyone has published them I'd say he might have some examples. He might even chime in on this thread and point you to the links if they exist.

 

[BrownyJones]

Hi Pfunk - you and Kolbi usually point out and ask the questions that I am also thinking but am usually too lazy to write up clearly. In regards to your last point, I was able to spend some time with an extremely well known PS vendor evaluating "superideal" AGS 000 stones versus the middle of the pack GIA triple excellent. My wife, who has a very keen eye was able to pick out the GIA XXX but she did not feel there was much difference with the AGS stones and would definitely not pay 10k more a superideal AGS000 at the expense of the other C's. In fact she ended up telling me later that she basically made a good guess. We were also able to view a few more AGS000 stones in a brick and mortar store which only had superideal stone. There were no GIA or lower grade AGS stones to compare. While there I was chatting with a fellow customer who was there because he wanted the best cut stone possible, and said that he is extremely educated on diamonds and recommended the PS website where he gained all of his knowledge.

I think TexasLeaguer said it best earlier: "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."

The difficulty with words like top-quality and ultimate is where my lawyer would earn his pay. To me the problem with these pseudo spectroscopic images is that they have no reference points or more significantly no units of measurements. Theres white under the table, there's a lot of white under table, it's all white under the table?

It's often mentioned here that the consumer had shifted to superideal stones and the tides are changing. I'm not so sure about that. Because of the internet, some are able to be convinced by these pseudo spectroscopic images and think they are getting the farraris and lamborghinis of diamonds, but in reality they will realize that it's more likely they have atomic watches in casio cases that look like every one else's very good casios and will let you know when it's time for lunch, but just much more precisely than the other guys.

 

[KobiD]

Thanks to those who have chimed in on the video. I had actually been questioning if the effect of a dirty diamond could be captured on ASET/IS, and have seen first hand the difference it can make in light return. I even started a thread here ([URL='https://www.pricescope.com/community/threads/that-clean-diamond-sparkle-the-importance-of-cleaning.211106/']https://www.pricescope.com/community/threads/that-clean-diamond-sparkle-the-importance-of-cleaning.211106/[/URL]) asking for some examples. It appears I had found the answer I was looking for, without knowing I was seeing it.

As pfunk states, though, it does make sense for a clip to promote their top tier product and ensure that it out performs the comparison. I have watched quite a few of Rhinos GOG comparisons and have found them quite helpful. Would anyone with access to multiple diamond, a macro setup, and some scopes be willing to do a similar comparison?

I like your input and analogy Browny. It's probably one of the best I've seen to date. The internet has indeed played a large part in advocating the importance of cut (and an important aspect it is!), but from my experience the more you read, the more you research, the more you find yourself funnelled towards the super-ideal requirement (even if at expense of other attributes). You could argue that if you were buying a watch, wouldn't you want it to read as accurately as possible? I mean, when you are spending on a watch, what's a bit more money for a bit more functionality (even if its not a neccessity).

For what it's worth, I would love a precision cut diamond! There is something about the workmanship that makes me want one. That someone has gone above and beyond to ensure the work is top notch! That's something I can appreciate (even if it makes no difference in terms of performance or beauty).

At the same time, I'm not overly fond of the eye clean SI1 (so often recommmended). While in most scenarios the inclusions won't be visible, but in some they will, and they will always be there. I think I would rather an ideal (high level of symmetry) with VS clarity, over a super-ideal SI. But that is what it all boils down to. Its a personal decision based on what you feel is important. I have come to that conclusion myself, while the general consensus would be to sacrifice the clarity and invest more into precision. Neither are right or wrong.

 

[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?

Yes I saw that right away, it invalidates the entire comparison.
Also the Diamond dock where these are being compared is less than ideal for simulating customer lighting.

How was symmetrical the light environment in these movies?

In this video probably pretty poor.

The differences shown in this video cannot simply be attributed to a slightly shallower crown and reduced optical symmetry.

This is why I love having the experts around. You pick up on stuff that I (less educated consumer) often overlook. I didn't consider they could have dirtied up the diamond that they wanted to look inferior, and also put it under lighting that would make it appear worse than their branded stone. The video likely has some bias that I didn't even consider but undoubtedly should have.

It would be awesome to see some completely unbiased videos to draw comparisons, as it is nearly impossible for the consumer to go somewhere where they can view these diamonds side by side in an unbiased environment. I'd love to see a diamond cut to the zenith of GIA excellent side by side with the superideal in conditions like Serg mentioned earlier.

Dirty diamond for comparison tests is very old sales trick . It is not necessary to dirty reference diamond. it is enough to clean carefully just one diamond which you want to sale now.
other non obvious options for co to give handicap which are not obvious for consumers:
1)Milkiness
2)difference in colour( for example E colour diamonds is more bright than H-I colours. Usually Consumers does not see the difference in colour from table view between E and H, But he can see difference in brightness due such difference in colour. the difference in brightness can be very high if Diamond with lower colour is slightly greyish ( Diamond receive colour downgrade due greyish instead yellow saturation)
3)special light conditional( highly symmetrical light environment can gives enormous benefits for highly symmetrical diamonds if you adopt positions and distance between diamond and light. BS uses it.
in certain positions a symmetrical light can gives many flashed for highly symmetrical cut and few flashes for diamond with less level symmetry . but in real consumer light environments ( pure asymmetrical ) a symmetrical diamonds have not such handicap and can lose against same asymmetrical diamond.
same light environment can be symmetrical for one symmetrical diamond and asymmetrical for second diamond in pairwise live tests.
You have just locate symmetrical diamond in line with Light environment internal axis symmetry , then second diamond will automatically receive asymmetrical light environment. after this you need just find position then first diamond will receive many flashes and take shot.

 

[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).

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

Good enough hearts for your ACA line?
Expert Selection Line?

Not Good enough for HRD standard.

There are a lot of examples of "close" but not "good enough" but does it make sense to save weight(to get above the magic 1.5ct) by cutting practically the deepest pavilion rounded to 41.6(41.8 is the limit with 59% table) that can still get the GIA Ex cut grade and then give it back by putting in the time and weight loss trying to get near ideal symmetry? It still has to be a saleable stone but beyond that this is a value losing proposition.

Was this priced like a 1.3ct TIC or more?

 

[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.

Good enough hearts for your ACA line?
Expert Selection Line?

Not Good enough for HRD standard.

There are a lot of examples of "close" but not "good enough" but does it make sense to save weight(to get above the magic 1.5ct) by cutting practically the deepest pavilion rounded to 41.6(41.8 is the limit with 59% table) that can still get the GIA Ex cut grade and then give it back by putting in the time and weight loss trying to get near ideal symmetry? It still has to be a saleable stone but beyond that this is a value losing proposition.

Was this priced like a 1.3ct TIC or more?

The hearts are not good enough for ACA. And the stone would have had to pass the AGS LP system as triple zero. In any case, the leakage would have disqualified it.

The hearts would qualify for Expert Selection, but other aspects of the stone would cause it to be downgraded to our Premium Select category.

Regarding cost, I would assume it was priced aggressively. Price considerations are normally what drives our virtual business, at least in rounds.

Regarding your point about cutting strategy, I think we have seen and are seeing many shifts in what manufacturers are targeting. H&A, in and of itself, has become an important characteristic to aspire to because market awareness/demand has grown significantly in recent years. And the skills and technologies to support high precision cutting have likewise been developing rapidly. Therefore many of our assumptions, which were correct just a few years ago, are being challenged today.

Again, I think we are at the beginning of a sort of renaissance for diamond cutting where the overall philosophy has started to tip in the direction of cutting for beauty. And I believe it will only gain momentum. It's a challenging time, but an interesting and exciting one for anyone involved in the industry.

 

[D_]

Hi pfunk,

Perhaps you've seen this thread:
https://www.pricescope.com/community/threads/need-help-with-this-rb.216388/

An example of good numbers, not poor but not perfect idealscope either.
How the diamond looks irl (whether the difference from one w/ perfect IS) is a different matter.

 

[gm89uk]

I think that you should consider the issue with some more info. What is the value of these numbers? Considering that GIA is generally the most used lab, this is the situation regarding GIA-reports:

1. The number on the report is the average of 8 individual measurements. There is no info on the report to what extent the individual measurements are close to or far off that average. Now, one may possibly agree that light performance is predictive, but if 2 equal numbers can mean 2 totally different realities, one cannot truly consider these numbers predictive, no?

2. Furthermore, the number on the report is rounded. 40.6 in PA may mean anything from an average of 40.51 to 40.69. A 34.5 in CA may mean anything from 34.26 to 34.74 average. Again, with so many potentially different realities behind one number, how can one consider such number to be predictive of light performance?

3. The report says nothing about the actual position of the facets, whose average angles are measured. What a diamond does with light not only depends on the individual angles of the facets, but also on the exact position of the facets. That info is unknown.

For those simple technical reasons only, it is already theoretically impossible to deduct a predictive light-performance score from these numbers only, let alone have practical results. As so often, the GIA-report is a rejection-tool, not a selection-tool.

Live long,

Thanks for such an interesting thread pfunk.
On this topic with GIA rounded numbers I believe you can make a very educated guess at where the numbers have been rounded from. I agree the range can take you from HCA excellent to very good and sometimes even good. I've been playing around with this. Looking at all the variables given in a GIA report there are only set combinations of crown angles, pavilion angles, table angles that will add to an exact depth of x%. There are only specific combinations that will also correspond to a carat weight of y. I've made a little program for fun that will test billions of combinations and tell you the likelihood of whether the angles are more than the stated or less based on the diamond dimensions stated. Tested against Sarin reports it works very well in predicting which side GIA rounded from. I can't share it because of forum rules but I am just stating for purpose you CAN reverse engineer a GIA report without a sarin report to tell from where it was rounded.

with this diamond here [URL='https://www.pricescope.com/community/threads/diamond-should-i-bite.144057/']https://www.pricescope.com/community/threads/diamond-should-i-bite.144057/[/URL] I can calculate that the average pavilion angle MUST mathematically be 40.9 and the crown angle must be greater than 35, as reflected in the Sarin report.


pfunk I did a little experiment of searching jamesallen for AGS excellent symmetry, excellent polish with only very good cut to try return all diamonds knocked for light performance (AGS00x) and found none that had ideal range.

 

[pfunk]

Hi pfunk,

Perhaps you've seen this thread:
https://www.pricescope.com/community/threads/need-help-with-this-rb.216388/

An example of good numbers, not poor but not perfect idealscope either.
How the diamond looks irl (whether the difference from one w/ perfect IS) is a different matter.

Hey D_... I did see the thread and the IS image. I am not sure that it is showing a bunch of leakage or if it is just strongly backlit and/or the stone isn't aligned perfectly leading to the apparent leakage on one side. This is one of the issues I have with IS images from many different vendors. There isn't a universal lighting setup so every vendors images look different. It becomes hard to tell what is leakage and what isn't. But thanks for linking that thread, it very well might be a stone with great numbers and some leakage!

 

[D_]

I am not sure that it is showing a bunch of leakage or if it is just strongly backlit and/or the stone isn't aligned perfectly leading to the apparent leakage on one side. This is one of the issues I have with IS images from many different vendors. There isn't a universal lighting setup so every vendors images look different. It becomes hard to tell what is leakage and what isn't. But thanks for linking that thread, it very well might be a stone with great numbers and some leakage!

That's interesting. Didn't think of that before.
I'd assume the vendors would try to present the diamond in the "best possible light", hence they'd like to ensure they capture the "best looking" IS images.
Though I guess wanting to do it and being able to do it are 2 different things.
If not, then there may be gorgeous looking stones that get "disqualified" just because the IS image could have been taken better - seems really unfortunate... But I guess that's why the top vendors are the top vendors, being able to capture the images well and accurately takes an investment.

 

[Titan7]

Great post, as I have spent about 50 hrs min researching super ideals on all the big super ideal sites.
Where I am having issues is following the advise often provided on the diamond help sites to stay in the middle of the specs. I have check out WF, BG, infinity, and others and looked at at least 100 super ideal stones, it's almost like there is a trend to cut towards the edges of the specs. 80% of the stones I saw had the following ranges:
TD: 61.5- 61.9
CA: 34.7-34.9, most were 34.8
PA: 40.7-40.9, most were 40.8

If staying in the middle is best why are most at 34.8/40.8?

I have also read if the CA is near 35 you want the PA at 40.6??

I also can't find H&A imagines the are 100% free from some type of deformity so I am at the point of just buying as I can't find the right combo as there are too many variables, most frustrating. I found what I though was a great WF AGS diamond but am wondering if the specs are at the edge and there is more middle of the spec stones out there.
61.9 td
55.7 table
34.8/15.4 crown
40.8/43.3 pavilion
78% lower girdle
53% star
Thin-med girdle

About to blow a gasket, lol

 

[craiguk]

Reading your post if most are 34.8 and 40.8 then that is bang centre of the ranges you've seen of 34.7-.9 and 40.7-.9

Unless I've read it wrong.

You're already looking at parameters that are heavily reduced. Why be concerned over tightening these parameters even further on your own? There's a reason why they cut to a range of parameters and not exact measurements to the decimal point.

If you've seen a nice ACA stone I don't see any reason whatsoever to obsess over its angles. They've already done that for you. The more you look the more you'll find it difficult to find something 'perfect'. In choosing a super ideal cut you've already omitted 95%+ of the stones available (according to some super ideals are within the top 1% of diamonds - can't recall where I read that though).