Wriggle Room in Paul Gias Ideal Proportions ?

[Rockdiamond]

I certainly am- I wouldn't use the particular brand suggested- but only because I can find a super ideal in our own safe.
I'd have to see about finding a great 60/60.
We don't have one in stock. And they're harder and harder to find.
The current state of the market is what I was fighting against- even all those years back with you old friend.
If technology can dictate design, and the market forces get swept up in it, you may eliminate diversity in design, Which is how the RBC market seems to look now.
Pretty much everyone cutting stones to look like "Ideal" cuts. Be they masterpieces, or be they weight savers.

 

[Garry H (Cut Nut)]

There are plenty of F/G VS2 1 to 1.05cts on Rapnet David, but most are of course shallow crowns, because that is why the larger table is polished - they are usually these days as a result of offcuts from larger stones.

 

[diagem]

There are plenty of F/G VS2 1 to 1.05cts on Rapnet David, but most are of course shallow crowns, because that is why the larger table is polished - they are usually these days as a result of offcuts from larger stones.

I am barely involved in the RB world but I personally have been noticing most triple X's are cut to lower CH's within the 13-13.5% zone. If this is the case then I suspect it's due to generic planning techniques used to divide a single rough crystal into 2 or more subdivisions.

Can you Garry or David do a search based on CH%? It would be interesting to see, if those are statistically plentiful as I was able to observe then it's a cutting habit caused by inefficient planning.

 

[Garry H (Cut Nut)]

I am barely involved in the RB world but I personally have been noticing most triple X's are cut to lower CH's within the 13-13.5% zone. If this is the case then I suspect it's due to generic planning techniques used to divide a single rough crystal into 2 or more subdivisions.

Can you Garry or David do a search based on CH%? It would be interesting to see, if those are statistically plentiful as I was able to observe then it's a cutting habit caused by inefficient planning.

Hi Yoram, I doubt that. Most stones have a larger an a smaller stone taken from them. Bishops hat. there are many more under 1/2ct low crown height and many more +1ct 15% crown height stones on the market.

 

[diagem]

Hi Yoram, I doubt that. Most stones have a larger an a smaller stone taken from them. Bishops hat. there are many more under 1/2ct low crown height and many more +1ct 15% crown height stones on the market.

So you think it's not getting two 13.5% CH RB's out of one crystal that is being populated on the market?

 

[Rockdiamond]

Hi Yoram, Garry
Always nice to see you!
Yes I can search by crown height %
What specs should we use to check your theory?
For the posts in this thread I have been searching for RBC with no color clarity or size restriction- and choose XXX and /or 0 cut grade.
Then we get the largest pool. Or if you have another suggestion.

 

[diagem]

Hi Yoram, Garry
Always nice to see you!
Yes I can search by crown height %
What specs should we use to check your theory?
For the posts in this thread I have been searching for RBC with no color clarity or size restriction- and choose XXX and /or 0 cut grade.
Then we get the largest pool. Or if you have another suggestion.

Thanx David, it would be interesting to see even though Garry doesn't think so, so yes, do the same search but let see how many in the GIA tripleX have 13-14%ch vs 14-15.5%ch?

 

[Karl_K]

Thanx David, it would be interesting to see even though Garry doesn't think so, so yes, do the same search but let see how many in the GIA tripleX have 13-14%ch vs 14-15.5%ch?

I am interested in this also I am seeing a lot of giaX ~33 degree(lower CH) crown angle stones pop up with tables ranging from 55 to 60 even in the 1ct range than I have seen before.

 

[Garry H (Cut Nut)]

If you guys want to do that you will find most stones have crown angles not crown height. So its a harder task. Also why not do below 14 and above 14. Why rule out 16 and 12?

 

[Garry H (Cut Nut)]

Also one reason there are more larger shallow stones is there have been many more larger rough diamonds found over the past decade.
Junior miners buy old De Beers mines and introduce pre and mid crushing Xray fluorescence scanning.
So those larger rough stones are more likely to yeild stones where reduced crown height increase yeild.
You must all have noticed in regular news media there are many more +100ct rough discoveries. Often at small miners properties

 

[Rockdiamond]

here's the results of a broad search. RBC XXX GIA
The only search parameter is crown height %
I used .1 to define the lower paratemter but GIA rounds to .5
11.1-12% crown height percentage. 1k stones
12.1-13 52,6k
13.1-14 69k
14.1-15 135k
15.1-16 118k
16.1-17 15k
17.1-18. 20 stones

The weird one was 10.1- 11% crown height. There were 5 stones - 3 of them IF - all from the same cutter.

 

[gm89uk]

Rockdiamond thank you for sharing your story and Texas Leaguer thank you for your kind words, I'll certainly give it a read when I get the chance. I remember a few months ago it was made available for free posted here on PS.

Just from reading the last few posts, a few points:

GIA includes diamonds that are more "sparkly"- because they lack the patterning of H&A.

Through a few the posts I get the impression you mean perfect optical precision can contribute to reduced scintillation? All things being equal, a 60:60 stone with less optical symmetry can have more observable scintillation? If that is the case, how does one of the stones you are describing online, if optical symmetry may be detrimental to perceived performance.

Is this 'sparkle' from lack of H&A patterning limited to 60:60 stones or do you think it's applicable to tolk stones. As such do you think 'ideal' stones' can be better than 'superideals' or merely that people don't notice much difference between them?

Additionally are the angles you've seen in those great stones outside of AGSL000 proportions?


Texas Leaguer, the ray tracing technology is fascinating and a great concept. But I think while most AGSL000 are great stones, some would be outright rejected by the pricescope community. I understand it's tested against the various subcategories (Brightness, Fire (dispersion), Leakage and Contrast) and if there is score greater than x in any of the subcategories then it is demoted from AGS0.

https://www.jamesallen.com/loose-di...arat-j-color-si1-clarity-ideal-cut-sku-564468
Stones like this however have made it through. I understand you cannot comment on another vendors diamond but just wanted to use this to illustrate that there will be significant lack of H&A patterning, optical symmetry doesn't look great but it still made AGSL0 and I'm sure it will have the splintery scintillation you are referring to Rockdiamond. I don't understand why you feel AGSL0 is too narrow? I will have to ask again for examples of great stones that wouldn't have made AGSL0 (based on proportions alone).

Rockdiamond do you think a high proportion of the Winston diamonds you liked so much would have had the potential for AGSL0?

I find AGSL 0 a great concept, where most are cut with tolk ideal cuts in mind, but really the system allows for a large variety of stones.

Despite extensive research from AGSL, do we as consumers really have a right to knock someones 32.5/41.2 59 table diamond that wasn't demoted in fire and contrast tolerances of AGSL, even if it may be significantly reduced vs a 35/40.6 H&A; and if not, is AGSL too lax within its subcategories?

 

[Rockdiamond]

Welcome back gm89uk
The discussion has come around quite a bit since your last post.
I guess the best way to address the quote about sparkle : my perception is that the best examples of 60/60 80lgf will produce more virtual,facets- therefore reflections of light. So a greater number of reflective incidents but since they are smaller they are less bright than a direct reflection of pavilion facet though the table.
Sparkle.

Would Winston's best qualify for AGSL 0?
It's quite possible they could. But they did not look like typical "ideal" 0 stones.
You're correct vendors can't comment on stones from another vendor- so no comment on quality..... but I don't agree with your assumption that the stone you linked to would produce the type of light performance I have in mind.

Fire, as an isolated characteristic is RBC is simply far less important than other perceivable aspects to the vast majority of consumers in my experience.
You need contrast to produce pattering. Not everyone loves pattering in diamonds- making contrast less of an issue as well.

 

[Garry H (Cut Nut)]

here's the results of a broad search. RBC XXX GIA
The only search parameter is crown height %
I used .1 to define the lower paratemter but GIA rounds to .5
11.1-12% crown height percentage. 1k stones
12.1-13 52,6k
13.1-14 69k
14.1-15 135k
15.1-16 118k
16.1-17 15k
17.1-18. 20 stones

The weird one was 10.1- 11% crown height. There were 5 stones - 3 of them IF - all from the same cutter.

David my point was if you want real stats then you need to include all the stones listed on RapNet. There are more than 440k XXX in total, and 530k if you just cover the GIA Excellent Cut.
Also if you are going to do this you cant use your ideal-cut from your safe - you must compare to a branded stone with 3rd party endorsement (e.g. like one of Bryan's ACA's). Otherwise people may accuse you of cheating. And an independent party must be present. And you need to decide if the comparison is between stones of identical weight (then people know which is which - so its not blind) or stones of the exact same diameter.

 

[Rockdiamond]

No proble to re run searches with less restrictions Garry. Very good point.
So let's use all RBC on the list regardless of Pol/Sym/cut grade?

We do have branded super ideal CBI stones with third party endorsements on hand.
A test won't ever happen for pragmatic reasons of which you've just names a bunch

 

[Karl_K]

here's the results of a broad search. RBC XXX GIA
The only search parameter is crown height %
I used .1 to define the lower paratemter but GIA rounds to .5
11.1-12% crown height percentage. 1k stones
12.1-13 52,6k
13.1-14 69k
14.1-15 135k
15.1-16 118k
16.1-17 15k
17.1-18. 20 stones

The weird one was 10.1- 11% crown height. There were 5 stones - 3 of them IF - all from the same cutter.

interesting, thanks
It does tell us there are a lot of them out there.
Thinking about it further without historical data its impossible to tell is there has been a change.
The expanded list per Garry above would also be interesting.

 

[Rockdiamond]

I was just thinking the same about historical data Karl

If we could only run the same searches in 2006
I believe spread per carat has decreased over that time. But no way to prove that.

 

[Karl_K]

Welcome back gm89uk
The discussion has come around quite a bit since your last post.
I guess the best way to address the quote about sparkle : my perception is that the best examples of 60/60 80lgf will produce more virtual,facets- therefore reflections of light. So a greater number of reflective incidents but since they are smaller they are less bright than a direct reflection of pavilion facet though the table.
Sparkle

Its not that simple there are a lot more factors in the number of effective virtual facets than table size.
Its a fact that which size, shape and orientation virtual facets are effective is totally determined by lighting and viewer location.

In general however the table area has fewer and larger virtual facets than the area covered by the other crown facets. A symmetrical 60/60 has fewer virtual facets than a symmetrical tolk.
That does not tell you how those virtual facet interact with any given lighting and viewer however.

 

[diagem]

interesting, thanks
It does tell us there are a lot of them out there.
Thinking about it further without historical data its impossible to tell is there has been a change.
The expanded list per Garry above would also be interesting.

I agree with Karl, I bet if we can do the search now also based on dates we will be able to get a clearer picture about the last 2-3 years of production. can we limit dates based on posted Diamonds or even better GIA report dates?

 

[Texas Leaguer]

Texas Leaguer, the ray tracing technology is fascinating and a great concept. But I think while most AGSL000 are great stones, some would be outright rejected by the pricescope community. I understand it's tested against the various subcategories (Brightness, Fire (dispersion), Leakage and Contrast) and if there is score greater than x in any of the subcategories then it is demoted from AGS0.

https://www.jamesallen.com/loose-di...arat-j-color-si1-clarity-ideal-cut-sku-564468
Stones like this however have made it through. I understand you cannot comment on another vendors diamond but just wanted to use this to illustrate that there will be significant lack of H&A patterning, optical symmetry doesn't look great but it still made AGSL0 ...

I find AGSL 0 a great concept, where most are cut with tolk ideal cuts in mind, but really the system allows for a large variety of stones.

gm89uk,
I just cut the question and comments you had for me above. You make an important point about the range of potential AGS0 candidates. As we have discussed, you can get a 60/60 ideal. You can also get other combinations outside of the target for 'super ideal', which many folks here would not necessarily recommend. And this is especially true where the stone does not have good optical precision.

As you pointed out the AGSL ray tracer measures brightness, dispersion, contrast and leakage. Conspicuously absent from these metrics is scintillation/patterning. While research is ongoing on scintillation, AGSL puts this aspect in the category of 'taste'.

Some may prefer smaller more splintery sparkle, others bigger, bolder. Some may prefer a more precise pattern, others a more chaotic one. (this I am skeptical about!). In any case, these particular taste aspects are left up to the individual.

It is important to recognize that facet precision is an indirect factor in assessment of Ideal, in that the system is not just evaluating averages of facet measurements. Faceting faults that might be concealed in other systems, could very well result in leakage or other deficits which would be penalized by the ray tracer.

 

[Rockdiamond]

Bryan, it's interesting that you're skeptical about people not wanting patterns.... what you've termed chaotic.
To me, this is at the crux of the issue here on PS. In this forum, clearly the bias is FOR patterning and contrast.
In the real world it's not so nearly one sided. At least from the many thousands of consumers I speak with.
I also feel like this is an area where GIA and AGSL diverge. Part of why the GIA allows more combinations is that the GIA grade has a component of human observation.
My position is that a very fair percentage of the general population wants a very well cut diamond but not necessarily patterns ( H&A). I could argue that GIA agrees, based on the cut grade.

 

[Texas Leaguer]

David,
I'm not sure why you seem to designate yourself as the spokesman for the 'real world'.

There is good reason to believe that symmetrical patterns are pleasing to the eye. In fact, there has been research demonstrating that human beings respond positively to symmetry in the world around us.

Perhaps that is why there is a 'bias' for facet precision here on the forum. And elsewhere.

In any case, neither GIA nor AGSL impose that value on anyone. If you are a consumer who likes asymmetrical patterns in diamonds, you are in luck. You will have no trouble finding them.

 

[Rockdiamond]

Hi Bryan,
I am basing my statements on my experience in part.
But it's just common sense that tastes will vary on ANY subjective issue.
And you've also apparently applied for the real world spokesman job

Perhaps that is why there is a 'bias' for facet precision here on the forum. And elsewhere.

I do not believe that there's ANY proof that the general population prefers patterning contrast to increased scintillation/spread.
And my point about taste being subjective......neither of us can say for sure how many people are in each camp- but surely you can agree there are people in both camps.
It's entirely possible that since your company is known for patterned stones, the consumers you speak with only want that look- conversely maybe my consumers are, in general, looking for something else.
But I feel that here on PS, it's only a matter of who speaks the loudest. Get a bunch of vocal consumers taking one side and the issue gets distorted if you use the PS forum to decide how the general population feels. As you've pointed out even AGSL puts scintillation as a "taste" issue- which I could argue should encompass the entire discussion of cut grading.....but on this specific point, AGS is also making my case. Along with GIA which has placed more emphasis on scintillation based on the GIA EX cut grade.

 

[Rockdiamond]

Bryan- I agree with you on a lot of things- I agree that the majority of people are drawn to symmetry on some level.
Yet, they are also drawn to asymmetry.
I know we're both music lovers.
Some love the perfect harmonies, some are drawn to the dissonance. The best singers aren't the best because they sing exactly in tune.
To be clear- my personal preference means nothing to me in this discussion.
I would not dispute the fact that "true" Super Ideal Cut diamonds being mentioned here are uniformly gorgeous. Far from it.
I've only had the pleasure of personally inspecting one ACA, and it was beyond awesome.
Loved it.
If someone wants the look of a super ideal- then I say go for the real thing.
Using the chart is no guarantee they will get a stone as nice as the branded Super Ideals commonly recommended here on PS
But if we're advising general consumers in general- as opposed to Super Ideal shoppers, the parameters should be wider than those which are the subject of this thread, if the advice is designed to encompass a widely accepted definition of what a well cut diamond is. AGS and GIA both include 60/60 in the top grade- we've established that many times.
That has been my position for years- Tolk is lovely- but so is 60/60.

 

[Texas Leaguer]

David, my ear must be able to tolerate some dissonance, because I am a fan of Willie Nelson!
I guess when other aspects are good enough, dissonance of that nature just adds a distinctive flavor that makes the music more unique and memorable.
But in general I like harmonies and and guitars that are in tune!
Not a big fan of hardcore jazz as it is too asymmetrical for my ear and hard to figure out for my brain. But I love contemporary jazz (aka smooth jazz) with it's effortless and seductive rhythms.

* Note to Admins: please don't moderate this post. I promise it is related to diamonds

 

[Rockdiamond]

Ah Willie. Yes a good example.
I would site a comparison of Jeff Beck, and George Benson, as guitar players.
George Benson is perfect. Smooth as velvet.
Jeff Beck shreds the guitar with emotion. It's not "clean". But it moves you.

So in this discussion, Super Ideals are the George Benson of diamonds, and the type of lack of patterned 60/60 I'm thinking of is Jeff Beck.
The real point here is that the restricted parameters ( Pauls GIA ideal proportions) are designed to mimic super ideal diamonds...in itself a bit of a ripoff if you look at it that way. I know what goes into making a super ideal- and it's more than just numbers. The list is overly restrictive to the broad swath of consumers.

 

[Texas Leaguer]

Restricted parameters eliminate potentially problematic stones. Same principal as HCA. A helpful strategy for consumers looking for well cut stones.

If more diamonds in the market were cut from a philosophy of most beauty, there would not be such a 'broad swath' to sort through.

As a member of the trade you should be very judicious using terms like "ripoff" to describe another trade member's advice. Even if you disagree with the parameters.

 

[Rockdiamond]

OK, poor choice of term, I agree.
The list borrows principles and attempts to use them to mimic a certain idea ( Super ideal cut diamonds).
In terms of eliminating problematic stones, we disagree.
Maybe 6.3mm rounds are problematic if spread is an important consideration.
I mean, if one buys into the list, who needs companies that put the effort into producing true super ideals?
If a filter eliminates too many good candidates, it's not a good filter IMO

 

[diagem]

Oh god..., what will happen if the world was filled with super ideal Cut Diamonds?

Anyone thinks it will become the next generic? Or is it already?

 

[bmfang]

@diagem, for markets where super ideals are prevalent (eg the USA), they are effectively a commodity item these days (unlike those bloody beautiful Octavias you cut!)

For markets where poor makes are common in the retail space (like where I am, Australia), super ideals are more of a rarity. That's just my POV based on what I'm seeing in the Australian market as a consumer.