What makes CBIs "more contrasty" than other superideals?

[arkieb1]

@cflutist and others - the reason it "bothers me" is that there seems to be this notion that you can ONLY buy a stone with the specs someone just listed above from vendors that declare themselves as CBI dealers, and that to the best of my knowledge that just isn't the case.

I can buy a "Super Ideal" diamond from one of the small number of places that sell "Super Ideal" cuts and provided it has the same specifications (ie I spend the time and wade through their inventory and find one with identical specs) it's going to look exactly the same. The stones I've seen compared here that were H & A or "Ideal" stones mostly have not had identical specs to CBI stones. In the limited amount of cases where they have, mostly the people looking at the stones cannot see the difference.

No one has actually purchased to my knowledge 5 or more stones from various different "Super Ideal" vendors with near to or identical specs and run side by side ASET images and other quantifiable tests on the stones. In fact, what I'd like to see is the identity of all of the stones covered and people like you and others all viewing the stones in person and picking blindly the ones you like. Then, and only then if the CBI stones actually win, out of a line up with diamonds with identical specs, will I be more than happy to acknowledge that CIB is more than just consistently good diamond cutting and clever marketing.

 

[skypie]

IIRC, a recent poster actually compared several CBI stones and a non-CBI stone (but with similar proportions) in a blind test and could not pick out the non-CBI stone.

She did end up buying CBI anyway though, FWIW.

 

[diamondseeker2006]

I’ll be the first to admit that when it comes to math and/or the vast details of diamond cutting, I am NOT a/the guru. Generally speaking, when I want to better understand something, I look at the available data and simply try to draw possible/reasonable patterns and/or assumptions. Furthermore, I’m confident there is far more that goes into making CBIs the beautiful diamonds they are, and that I’m likely oversimplifying this. My post/observations are in no way intended to ‘question’ HPD, CBI, or those with a role in creating them, and I sincerely hope it’s not taken in that way.

I took a look this morning through the top 21 CBI diamonds on HPD site (“top” being the first 21 on the list, just to make it simple for me to go down the list), and made notes of the specs for each and compared them with what is typically recommended on PS to staying within ‘ideal’ range. My thought was, maybe there is some recurring pattern in the numbers that *might* explain the more ‘contrasty’ appearance that some CBI owners have commented on. I am NOT suggesting that my observations are in fact the reason for the contrasty appearance; it is merely a hypothesis based on my consumer observations (read: non-expert) that I’m sharing with the group for discussion/thoughts. So with that all said ...

So I’m ASKING (NOT suggesting): is it possible that a ‘secret sauce’ to the perceived more ‘contrasty’ look in CBIs may be to have a spec range somewhat like this:
Table: = or < PS rec median
Depth: = or > PS rec median
CA: = or < PS rec median
PA: = or > PS rec median
LH: = or < PS rec median
Star: > PS rec median

Or am I ENTIRELY in left field, and this has no bearing whatsoever?

You've done a lot of hard work for sure! But I am going out on a limb to say that most superideal vendors' stones here are using that same range of measurements. Yoram is talking about something beyond that. Back when I joined PS and I was first working with Jonathan when he was at GOG for a hearts and arrows stone, they actually did helium scans that gave incredibly precise information about measurement involving every facet, practically! We'd want the absolute best and tightest numbers! We were crazy in retrospect, because with hearts and arrows stones, there is a level of perfection that we can see, and anything beyond that we cannot see. I have seen superideal cuts from several vendors here over the years. We may have preferences on table size, crown angle, lower girdle facets, etc. But the first H&A stone I owned had the helium scan to prove it's perfection in cutting...or at least that was one component to prove it available at the time, and I have found that the other H&A stones I have seen and owned measured up equal to that stone. So my opinion is, buy CBI or buy WF, as both have outstanding H&A stones. Those are the ones who I believe are very particular and only have top cut stones in their signature lines (and good selections if you ever want to trade up).

 

[arkieb1]

IIRC, a recent poster actually compared several CBI stones and a non-CBI stone (but with similar proportions) in a blind test and could not pick out the non-CBI stone.

She did end up buying CBI anyway though, FWIW.

Yes - exactly I can think of two examples where people did this and they could not pick the CBI stones, all the other times where people have posted side by sides or videos the stones have NOT had identical specs or they have not been blind tests. And I don't think I've ever seen side by side ASETS and other quantifiable data conducted without bias by the same place, side by side comparing stones with the same specs.

 

[the_mother_thing]

You've done a lot of hard work for sure! But I am going out on a limb to say that most superideal vendors' stones here are using that same range of measurements. Yoram is talking about something beyond that. Back when I joined PS and I was first working with Jonathan when he was at GOG for a hearts and arrows stone, they actually did helium scans that gave incredibly precise information about measurement involving every facet, practically! We'd want the absolute best and tightest numbers! We were crazy in retrospect, because with hearts and arrows stones, there is a level of perfection that we can see, and anything beyond that we cannot see. I have seen superideal cuts from several vendors here over the years. We may have preferences on table size, crown angle, lower girdle facets, etc. But the first H&A stone I owned had the helium scan to prove it's perfection in cutting...or at least that was one component to prove it available at the time, and I have found that the other H&A stones I have seen and owned measured up equal to that stone. So my opinion is, buy CBI or buy WF, as both have outstanding H&A stones. Those are the ones who I believe are very particular and only have top cut stones in their signature lines (and good selections if you ever want to trade up).

That’s awesome that GOG provided that level of evidence to ‘validate’ that you were getting a superb diamond; amazing really! And I would agree (with the bolded statement), but I did note that in looking through the CBI numbers, that they do largely appear to be a consistently ‘tighter’ grouping within the ideal specs recommended on PS. That’s not to say WF doesn’t do the same for ACA, but they publish their ACA spec ranges on their website and they seem to be a bit more ‘tolerant’ than what I noted in CBIs - at least, the 21 stones’ specs I looked at; that’s why I wonder if CBI’s approach or ‘secret sauce’ is a ‘tighter’ range of numbers that falls more inside those super-ideal/ideal ranges, and that combo is what gives them the consistent ‘contrasty’ appearance. But to the ACA specs’ credit, I can appreciate having more tolerance for a variety of combinations within those ideal specs producing beautiful, super-ideal diamonds that appeal to the varying flavors people love, such as what you suggested with regard to table/crown/LGF facets, etc.

What I take away from all of this is: CBIs ‘formula’ seems to result in almost every super-ideal diamond they cut having a like appearance, and the ‘ACA’ formula perhaps allows for more variety and individuality in each super-ideal diamond they cut. So it really seems to come down to what the super-ideal buyer wants (in addition to a lot of other things, obviously): more consistency in appearance from stone-to-stone that appeals to their eye, or perhaps more variety to choose from when buying that appeals to their eye.

And I’m just hypothesizing here ... I don’t have a dog in this fight either way. I’ll wear & love my WF ES (once it’s set & back in my hot little hands) with much love regardless. It’s more just the curiousity that has me hypothesizing, asking questions, and participating in the discussion. If I am ever near a CBI dealer, I’ll be sure to make a point to see the CBI in person so I can have an in-person visual comparison.

 

[diamondseeker2006]

@the_mother_thing On your list, CBI had crown angles from 34.1-34.8 which is pretty much the range you'll actually see at WF. I don't really have the energy to look at that many WF stones to compare, but I just know from my own searches and searches for other people that most of the stones will fall in that range, and both try to keep depth less than 62, etc. The PS recommended range is only trying to hit ideal cut standards, with generic GIA Ex stones, so we can't compare that to superideals. The superideals are cut to a higher level of precision than almost any virtual stones on other sites. I think if we had two G VS1 stones with the same weight, diameter, same table, crown and pav angles, and depth, there is no way we could see the difference with our eyes.

I think it is great that you are participating AND learning in the process! And yes to seeing as many top quality stones as possible!!!

 

[the_mother_thing]

@diamondseeker2006 Thanks for entertaining my thought process, and appreciating that I’m trying to understand & come at this from a neutral perspective vs. taking any one side.

I get that the range recommended for the ‘generic’ GIA XXX diamonds is just to help narrow down those which might be in the range of ‘ideal’, but I would think that super-ideals would have to fall within some segment of that same range (obviously taking into account additional more in-depth factors as well that may be outside these basic criteria; in other words, I appreciate there is more to super-ideals than these numbers).

Just for ‘gits & shiggles’, I pulled the same numbers for WF - the first 21 stones on their ACA list, and here’s what I found presented the same way as the CBI #s from earlier, and for simple comparison purposes, I’m re-posting the two sets of numbers together (ACA top followed by CBI in both sets of images)






What immediately jumps out at me is that the majority of ACA specs fall in the =/> spectrum of those ideal-recommended specs vs. the CBI specs, which are about half < and half >, and in ways that I think would make sense visually. When talking specifically about visual perceptions of ‘contrast’, it kind of makes me wonder if that is what differentiates the viewers’ perception - because I would think that more differentiation between table vs. depth and crown vs. pavillion *could* yield such a result than if those numbers were less different.

I hope my thought process is making sense here.

 

[CareBear]

I also did a search on the HPD site today and eye-balled the stats of a bunch of CBI stones. I did not find anything stats wise, that particularly stood out, compared to other super-ideal vendor's stones. But THIS did stand out for me.

CBI
5.12 I VS2 $145,031 (non-wire)

Compared to an ACA
ACA
5.198 I VS2 $110,017 (non-wire)

Below are the details of the two:
CBI
11.03 - 11.08 x 6.84 mm
Table 56.0%
Depth 61.8%
Crown Angle 34.4
Pav angle 40.8
Star 48
Lower 77

ACA
11.20x11.26x6.87 mm
Table % 55.7
Depth % 61.5
Crown Angle 34.4
Pavilion Angle 40.8
Star 52.0
Lower 78

I have never seen a CBI in person so I do not know how they compare to ACAs. But it got me thinking, how much 'better' would the CBI have to 'perform' for me to pay the extra 30% (if I were buying a 5ct, which I am not)?

 

[the_mother_thing]

@CareBear That is a pretty steep price hike ($35K) for ~ .2mm smaller in spread for an otherwise comparable diamond, so I would definitely insist at that price point (and several below it if like stones) to see the difference with my own eyes to justify it, and even then, it’d have to pretty much make me moan daily to warrant me spending the extra Benjamins.

This is one of the reasons I am soooo thankful that I don’t have the ‘eagle eyes’ others do when it comes to minor variances in performance and color grades because it keeps my wallet happy.

 

[Dancing Fire]

I also did a search on the HPD site today and eye-balled the stats of a bunch of CBI stones. I did not find anything stats wise, that particularly stood out, compared to other super-ideal vendor's stones. But THIS did stand out for me.

CBI
5.12 I VS2 $145,031 (non-wire)

Compared to an ACA
ACA
5.198 I VS2 $110,017 (non-wire)

Below are the details of the two:
CBI
11.03 - 11.08 x 6.84 mm
Table 56.0%
Depth 61.8%
Crown Angle 34.4
Pav angle 40.8
Star 48
Lower 77

ACA
11.20x11.26x6.87 mm
Table % 55.7
Depth % 61.5
Crown Angle 34.4
Pavilion Angle 40.8
Star 52.0
Lower 78

I have never seen a CBI in person so I do not know how they compare to ACAs. But it got me thinking, how much 'better' would the CBI have to 'perform' for me to pay the extra 30% (if I were buying a 5ct, which I am not)?

I can't afford either one...

 

[diamondseeker2006]

That's astounding that they have 2 stones at 5 cts so similar. The pricing almost looks like there's an error.

 

[CareBear]

Anyone have $250k lying around, who can order these two puppies for a comparison video?

 

[the_mother_thing]

Anyone have $250k lying around, who can order these two puppies for a comparison video?

Checks online banking

 

[CareBear]

Checks online banking

I don't need to check to know...

 

[the_mother_thing]

I don't need to check to know...

Maybe we can start a GoFundMe, then donate the $ to charity after the diamonds are returned.

Win-Win

 

[pyramid]

The Idealscope I looked at was different in that the contrast leakage is at the star facets instead of the top of the upper girdle facets on other diamonds. As the painted stones used to have no contrast leakage due to painting I asked if they were painted in that way too. Ofcourse no one is replying about their design in the way we were told these things before. There is contrast leakage as I said on the star facets. There is probably other things they can do other than painting, so not ofcourse insinuating that is what it is, just that the Idealscope shows red there with no contrast leakage. They are beautiful stones.

 

[Dancing Fire]

Anyone have $250k lying around, who can order these two puppies for a comparison video?

Links please. We can also throw this one in and do the Pepsi Challenge at the PS GTG.
https://www.briangavindiamonds.com/...-ags-c-104096006005#!prettyPhoto[gallery2]/3/

 

[CareBear]

Links please. We can also throw this one in and do the Pepsi Challenge at the PS GTG.
https://www.briangavindiamonds.com/...-ags-c-104096006005#!prettyPhoto[gallery2]/3/

https://www.hpdiamonds.com/en-us/diamonddetail/HPD10026

https://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-3840002.htm

 

[gm89uk]

These two might be more realistic comparisons?
https://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-3858601.htm
https://www.hpdiamonds.com/en-us/diamonddetail/HPD7791

This has always been my hunch too.

but I did note that in looking through the CBI numbers, that they do largely appear to be a consistently ‘tighter’ grouping within the ideal specs recommended on PS. That’s not to say WF doesn’t do the same for ACA, but they publish their ACA spec ranges on their website and they seem to be a bit more ‘tolerant’ than what I noted in CBIs - at least, the 21 stones’ specs I looked at; that’s why I wonder if CBI’s approach or ‘secret sauce’ is a ‘tighter’ range of numbers that falls more inside those super-ideal/ideal ranges, and that combo is what gives them the consistent ‘contrasty’ appearance.

 

[pfunk]

Curious to know if there has ever been a blinded test between the various vendors? Perhaps at something like the Pricescope get together event? Anyone here feel confident that they could consistently pick out a certain brand from a lineup of stones without a loupe?

 

[diamondseeker2006]

Curious to know if there has ever been a blinded test between the various vendors? Perhaps at something like the Pricescope get together event? Anyone here feel confident that they could consistently pick out a certain brand from a lineup of stones without a loupe?

They'd have to put out about 50 stones (of the same color and clarity so that didn't influence the choices), because someone could be lucky and choose the right one out of 5. But I am going to say no, if there were 5 stones of a certain brand within the 50, I do not believe someone could pick out those 5 stones with our without a loupe.

 

[missy]

They'd have to put out about 50 stones (of the same color and clarity so that didn't influence the choices), because someone could be lucky and choose the right one out of 5. But I am going to say no, if there were 5 stones of a certain brand within the 50, I do not believe someone could pick out those 5 stones with our without a loupe.

Yes I agree with this. And this is the heart of the issue IMO. If they all look bright and beautiful with your eyes for most of us that is what matters. We aren't walking around viewing our stones through loupes the majority of the time we are wearing them. Yes, for sure there are some academic perfectionists (nothing wrong with that) who want everything to be as perfect as possible loupe wise and they have vendors to choose from to find their dream stone. For most of us many of these vendors can provide a gorgeous stone that perform beautifully. And it just comes down to the flavor you want and within each vendor there are many different looks you can choose.

YMMV and fortunately there are a myriad of wonderful vendors to choose from and thank you Pricescope for educating us and allowing us to share info and photos and experiences. PS and PSers collectively ROCK.

 

[yssie]

The discussion about what tale numbers may tell needs to account for the reality of scanner error - especially when we’re talking about the sorts of nuances that differentiate brands of superideals. Sarin, for example, lists error on various models as +/- 0.1-0.2deg (angular) on their site. Garry has noted numerous times that light reflector tools like IS/ASET have real-world sensitivity limits.

Two stones with identical numbers will not be identical. They’re certainly going to be awfully similar. Is it possible that one is “better than the other”? I believe a skilled cutter with a goal can design and create a more detailed story than scanner output or IS/ASET/H&A scope photos would be capable of representing.
Should that matter to a consumer? That really depends on what the consumer is looking for.

 

[LLJsmom]

I swear this may be just me and definitely just a theory. I think how much time you spend with a stone matters. I am going to use myself as an example. I think that if I had two stones, again using CBI and WF as an example, same specs, set in the same setting and that I owned them for a number of years, over time I would be able to tell which is which by getting to know them. I might be wrong. I wish I had this problem.

 

[Lula]

I swear this may be just me and definitely just a theory. I think how much time you spend with a stone matters. I am going to use myself as an example. I think that if I had two stones, again using CBI and WF as an example, same specs, set in the same setting and that I owned them for a number of years, over time I would be able to tell which is which by getting to know them. I might be wrong. I wish I had this problem.

Yes, this has been my experience. The longer you live with a stone or a brand, the more you're able to discern the subtle differences in cut or personality. I've owned several CBIs. The sharp, crisp, contrasty look is remarkably consistent from stone to stone. I know I could pick CBI stones out of a line up, and I'm sure @cflutist, and others who have owned CBI stones, could, too. In my view, the secret sauce is the stones' consistency from one stone to another. How that consistency is achieved is beyond the scope of what I learned in my college level physics course. Consistency may not be important if your goal is to buy the biggest, well-cut stone for your budget and don't plan to upgrade. But consistency across the brand counts when you want to upgrade and/or if you want to match stones. I'm working on a five-stone CBI right now (Well, I've been working on it for two years; finally getting around to choosing a setting). Because I know that CBIs all have the same consistent look, it's very easy for me to choose stones (and swap them out if I want to change the proportions). Again, this discussion shouldn't be about which vendors' stones are "better"; we PSers are fortunate to have the option to work with many fine vendors who sell the best-cut stones. It's all about weighing your priorities and making the best choice for you given your budget and aesthetics. My undergraduate degree is in textiles and design. I see patterns everywhere, and I am very sensitive to deviations in patterns, so I appreciate cut precision. I can see the difference; others might not be able to.