60:60 vs Ideal MRB proportions – Is beauty in the eye of the beholder? Can one cut fit all?

[SimoneDi]

Alright folks, after the 60:60 vs. “Ideal” MRB proportions topic has emerged on multiple occasions in recent PS discussions, it is finally time for the topic to have a thread of its own!

I am certain that many members of the forum and members of the trade have much more experience and can provide much more insight that me, so I am looking forward to comment from others! (looking at you @Rockdiamond) Nonetheless, I shall begin with my personal experience and observations.

It is no secret that when it comes to MRB proportions, the majority of PS’ population will favor the so-called “Ideal” proportions. Such proportions are usually limited to the below:

Table: 54-58

Depth: 60-62.4 (although my personal preference is <62)

Crown angle: 34-35.0

Pavilion angle: 40.6-40.9 (41.0 if the crown angle is close to 34)

Why? Said proportions usually result in an excellent cut that will produce great light performance, which is the main reason we all love diamonds! Now, we know that in addition to the diamond’s specs, we also like to evaluate HCA score, ASET, Ideal scope and H&A images, which help us evaluate diamond’s performance & symmetry. When new members come in looking for advice, we* (*most of us) will always recommend ideal proportions for GIA stones and further even recommend AGS000 certified stones with Ideal light performance. More often than not, even if stones with proportions outside of the ideal parameters (assuming HCA <2, for example) have the potential to perform exceptionally, such stones will be rejected by the majority of all PS members. Are we all biased? Or can the average consumer really see the difference between “ideal” proportions and stones with potential which have specs outside of the recommended range. Can cut for MRB be standardized, or can we accepts a different “ideal”?

To this day, we continue to hear from time to time about some of the great 60:60 diamonds. I know, I know…”but that was before Ideal H&A…cutting has improved…tables greater than 59% are not as appealing…such diamonds demonstrate more brilliance than fire..” the list goes on. But one feature of 60:60 stones cannot be disputed – they do provide an amazing spread! Much greater than a diamond of same carat with depth of 62%. So I guess the question is – should 60:60 stones really be ignored? What if there were 60:60 stones with ideal light performance, would you still choose the above mentioned “ideal” parameters?

Well, my friends, I would like to share with you what in my opinion is an example of a great 60:60 stone!

A little bit of back story (If you don’t want to read through this, feel free to skip to the images), when my husband and I got engaged, we acquired an heirloom ring which had a chipped diamond. I loved color diamonds prior, but this was when I started learning more about round cuts and when I found PS (I was in lurker status for a while J ). PS helped me discover recutting options. My sole goal for the recutting process was to hopefully repair the chip that ran from the pavilion to the culet, but little did I know that the results would be so amazing. Mr. Brian Gavin recut my damaged stone and in order to salvage the majority of the diamond without sacrificing too much of the diameter, he transformed it into an H&A 60:60 diamond with ideal light performance! For your viewing pleasure, please see ASET, Idealscope, H&A image and AGS certificate below:










This little number was a real firecracker! Despite its shallow crown angle, it exhibited fantastic fire, I would absolutely say that it was comparable to the 3 stones I later acquired/upgraded that had “Ideal” proportions. The 59.6% depth made it appear equal in size to 0.72ct or so stones with ideal proportions. That was some major difference!

I am certain that the majority of folks here will continue to favor the before established “Ideal” proportions, but are we missing on some major coverage for ignoring 60:60 stones? Should we leave them in the past, or are we missing on some untapped 60:60 Ideal Cut diamond potential?

For those that made it through the entire, or 1/2, or 1/3 of the post – thank you Looking forward to hearing others’ opinions!

 

[gm89uk]

SimoneDi, mainly thanks for taking the time to write this thread I'm sure it'll be popular. I want to just quote DS from the other thread as I think it's one the main caveats of 60:60 stones.

What I think all these discussions miss is that ideal cut diamonds are a safe buy for those buying online. There may be many other combinations outside the ones I recommend that are acceptable. But the whole point is, people are coming here and we are helping them buy diamonds, mostly online, and I still say that I'd rather recommend stones with ideal cut proportions because they most likely will end up with a top cut quality stone. If one has the luxury of going to a vendor who specializes in well cut diamonds and can be shown an outstanding 60/60 with the light return images to prove it next to ideal cut stones, then that's the best case scenario. But I know I would have zero opportunity to do that because even the nicest jewelers don't worry about carrying the best of GIA XXX and AGS Ideal cut would be hard to find, period. So even those buying locally and are viewing all stones in jewelry store lighting are better off asking for stones within certain measurements, because it is hard to see variations in cut in that lighting.

Your stone is beautiful! Do you notice a different personality with this stone than with the others? Is it more splintery?

While your stone is fantastic, I've come across very little of them! Where do you go to buy a stone of that cut quality and precision? The superideal vendors don't cut to that proportion, including BG (who has beautifully cut that for you). The question is why, as I'm sure there is a market for it. There's an interesting thread by flyingpig about why there aren't superideal 35.5/40.6 stones and there are various considerations (that are nothing to do with diamond optical performance) and similar factors may play in here.

Rickdiamond has alluded to precision H&A cutting may compromise scintillation in 60:60 stones (I apologise if I misunderstood) so really are superideal 60:60 stones the best of 60:60? I know personally I would want my 60:60 stone near enough H&A but I have little real experience to make that call

 

[flyingpig]

60/60 is not really ignored. There are seasoned PSers who buy 60/60s. Some reputable vendors offer well cut 60/60s at a great price with flexible upgrade policy. But people just don't recommend it over TIC, just like I don't recommend 35.5/40.6. This is because TIC (57/34.5/40.7) is perceived as the best by many. It is like when you go to a watch forum, many recommend Rolex. I love and own Omega, but I tell people to buy Rolex. It is just more logical advice when all things are considered.
60/60 is a very broad category. I will gladly take balanced 60/60/34/40.6, but not bottom heavy and flat 60/60/32.5/41.2, and there are really bad cut 60/60s

 

[April J]

I was eagerly awaiting this 60/60 discussion. Thank you, Simone, for starting the thread! I've been reading all I can on 60/60 diamonds and I'm learning that the range of specifications is narrow to achieve a truly great cut.

Let me provide a real-time case study here for this discussion. I have a dilemma; I don't yet fully know how to interpret 60/60 diamonds for a great diamond. I want to ask the experts on PS if the cut of the 60/60 diamond we just bought is likely a great one:

https://www.jamesallen.com/loose-di...-d-color-i1-clarity-excellent-cut-sku-3059257

It is still at James Allen and we could easily return it if I wish to. It earned a 2.1 on the HCA tool. The IdealScope image is attached. If we approve it, they will set the diamond and mail us the ring, as we've already purchased it. If we don't approve it, we will receive a refund and continue the diamond search.

What I want is a very bright D close to 1 carat that is very sparkly to match the wedding band we bought that has extremely sparkly, ice white D mellies. I'm not too particular about inclusions. I just want a bright white lit-up diamond, nice black arrows for great scintillation, and awesome light performance in the sunlight and at night under street lights as we drive in the car And, I'm wondering if this diamond could be it.

For reference, purchase price was $4250 but we were willing to go up to $6500 if we had to in order to get a great performing, super white diamond.



Thanks!!!!!

 

[drk14]

Maybe I misunderstood the quote from @diamondseeker2006 , but is there an implication that it is impossible/difficult to distinguish between the "good" and "bad" 60/60 using the tools available to online consumers (dimension/angle data, reflector images, 360 video)? If this is the case, could someone explain why? On the other if this is not the case, then I don't understand the objection raised by @diamondseeker2006, and hope that someone can clarify the argument for me.

 

[flyingpig]

is there an implication that it is impossible/difficult to distinguish between the "good" and "bad" 60/60 using the tools available to online consumers (dimension/angle data, reflector images, 360 video)? .

I cannot speak for DS2006.
But speaking of various tools, unlike brightness/contrast/light leakage, there is no tool that visualizes dispersion/fire/scintillation, which 60/60 often lacks. Numbers don't give you the full picture. AGS000 can still have some deduction in dispersion. Most fire and sparkle videos available on youtube use heavily modified and unrealistic lighting conditions. Dispersion/fire/scintiliation is something hard to assess, capture, visualize or quantify. That's why it is important that you compare 60/60 and TIC in person to really learn what you are missing/gaining.

 

[drk14]

dispersion/fire/scintillation

Would you mind clarifying the terminology? My understanding is that fire=dispersion is the ability to get sufficient separation of different wavelengths so that some of the flashes appear to have color. However, I understand "scintillation" to mean something entirely different (related to having virtual facets that turn on and off as the diamond moves w.r.t. the light source). Are you using "scintillation" as a third synonym to fire/dispersion, or are you saying that we are not well-equipped to evaluate either fire/dispersion or scintillation?

 

[flyingpig]

Would you mind clarifying the terminology? My understanding is that fire=dispersion is the ability to get sufficient separation of different wavelengths so that some of the flashes appear to have color. However, I understand "scintillation" to mean something entirely different (related to having virtual facets that turn on and off as the diamond moves w.r.t. the light source). Are you using "scintillation" as a third synonym to fire/dispersion,

sorry, excuse me for poor grammar and the improper use "/". I never meant to say fire=dispersion=scintillation. The definitions of fire, dispersion and scientililation are here.
https://www.americangemsociety.org/Content/uploads/85441435072031.pdf
I won't even attempt to re-phase what AGS has to say.
And according to AGS, fire is not necessarily dispersion either. But those three are closely related.

are you saying that we are not well-equipped to evaluate either fire/dispersion or scintillation?

Correct, consumers are not equipped to evaluate fire, dispersion or scintillation, in comparison with how we evaluate brightness, contrast, and light leakage with the ASET and IS which visualize those properties in a relatively easy to understand manner

 

[April J]

Can anyone help me interpret the IdealScope image of the 60/60 I posted above? I am a newbie and it looks to me like the IdealScope image I posted shows a borderline 'ring of death.' Am I correct?

Thanks!

 

[Karl_K]

Firstly I think the term 60/60 is rather silly as a diamond description.
You can no more describe a diamond by 2 numbers than you can describe a person with 2 numbers. Would you describe a person as 5'6" 135 with no other information?

 

[Karl_K]

April J welcome to PS. Trade members are not allowed to comment on other vendors diamonds. Sorry I can not help you.
I can say the back lighting on that IS image is over bright making it look worse than it is.

 

[Karl_K]

SimoneDi,
A diamond like yours is exactly what I have been bugging David to offer for over a decade. There is nothing to dislike.

 

[diamondseeker2006]

Maybe I misunderstood the quote from @diamondseeker2006 , but is there an implication that it is impossible/difficult to distinguish between the "good" and "bad" 60/60 using the tools available to online consumers (dimension/angle data, reflector images, 360 video)? If this is the case, could someone explain why? On the other if this is not the case, then I don't understand the objection raised by @diamondseeker2006, and hope that someone can clarify the argument for me.

In addition to the comments flyingpig made, I'd just add that ASET images aren't often offered on many virtual stones aside from hearts and arrows stones. James Allen can get them on some stones, but not all, and they limit the customer to light return images for 3 stones. Blue Nile has limited availability, as well. I would also just say from a purely aesthetic viewpoint, I personally prefer a diamond with a nice high crown which is more visible with a smaller table. I don't find flat top stones very appealing. I think ideal cut stones do offer a good balance of light return, fire, and scintillation (excellent preferred), so it would be hard for me to recommend stones that aren't excellent those areas. I realize there are people who value size above all else, and those might be willing to sacrifice in other areas to get size. But I feel less inclined to recommend stones in those cases, because I value great cutting and performance and feel less confident on recommending stones that don't fall into ideal cut parameters. We just rarely see a variety of 60/60 stones with ASET images posted here on the forum. Simone's diamond looks lovely, but I also suspect most 60/60 diamonds wouldn't be cut with the precision that hers was by BG. He also recut a a large table, flat top family diamond for me with much improvement.

 

[diamondseeker2006]

I was eagerly awaiting this 60/60 discussion. Thank you, Simone, for starting the thread! I've been reading all I can on 60/60 diamonds and I'm learning that the range of specifications is narrow to achieve a truly great cut.

Let me provide a real-time case study here for this discussion. I have a dilemma; I don't yet fully know how to interpret 60/60 diamonds for a great diamond. I want to ask the experts on PS if the cut of the 60/60 diamond we just bought is likely a great one:

https://www.jamesallen.com/loose-di...-d-color-i1-clarity-excellent-cut-sku-3059257

It is still at James Allen and we could easily return it if I wish to. It earned a 2.1 on the HCA tool. The IdealScope image is attached. If we approve it, they will set the diamond and mail us the ring, as we've already purchased it. If we don't approve it, we will receive a refund and continue the diamond search.

What I want is a very bright D close to 1 carat that is very sparkly to match the wedding band we bought that has extremely sparkly, ice white D mellies. I'm not too particular about inclusions. I just want a bright white lit-up diamond, nice black arrows for great scintillation, and awesome light performance in the sunlight and at night under street lights as we drive in the car And, I'm wondering if this diamond could be it.

For reference, purchase price was $4250 but we were willing to go up to $6500 if we had to in order to get a great performing, super white diamond.



Thanks!!!!!

April, that stone does look nice, but I really cannot recommend an I1 clarity stone in most cases for an engagement ring. That stone has a very large and visible feather (crack) and that would bother me a lot. This is my personal preference again, but I'd go down to G color and VS2-SI1 clarity in a well cut stone any day before I'd buy a D I1. Or I'd go down to the .80-.89 and get a D VS2-SI1. You are combining the best color with the worst clarity which isn't balanced in terms of quality, to me.

As far as performance at night in the car from street lights, I would not feel very optimistic about that with most diamonds. At night, it is dark in the car (and most cars have tinited windows,too), so you really won't see much light return even as you pass a street light unless you hold your hand out the window, perhaps!

 

[flyingpig]

https://www.pricescope.com/communit...ave-this-diamond-on-hold-for-purchase.219921/
60/60/34/40.8
Lovely. I would buy.

 

[The6ixontherun]

What's the feeling on this 60/60?

Depth
60.0 %
Table
59 %
Crown Angle
33.5°
Crown Height
13.5%
Pavilion Angle
40.8°
Pavilion Depth
43.0%

 

[diamondseeker2006]

What's the feeling on this 60/60?

Depth
60.0 %
Table
59 %
Crown Angle
33.5°
Crown Height
13.5%
Pavilion Angle
40.8°
Pavilion Depth
43.0%

We rarely are going to approve a stone without an ASET image unless it is cut to the typical ideal proportions. I wouldn't take the risk otherwise. So if you can get the ASET image and video of the stone, please post in a new thread. But the numbers look promising.

 

[drk14]

I never meant to say fire=dispersion=scintillation. The definitions of fire, dispersion and scientililation are here.
https://www.americangemsociety.org/Content/uploads/85441435072031.pdf
I won't even attempt to re-phase what AGS has to say.
And according to AGS, fire is not necessarily dispersion either. But those three are closely related.

Thanks for clarifying what you meant. Although I did not read all 151 (!) slides in detail, I came away with the impression that "dispersion" is a measure of the potential to produce "fire" (colored sparkles), and that the AGS (and your) definition of "scintillation" corresponds closely to my own as written above ("having virtual facets that turn on and off as the diamond moves w.r.t. the light source").

Returning then to the points that you and @diamondseeker2006 have made, it is my contention that at least "scintillation" in 60/60 stones can be reasonably well evaluated from high-resolution video as long as the lighting hasn't been overly manipulated(much like we evaluate the performance of fancy cuts), while an educated guess regarding the potential for dispersion/fire can be made from the proportions of the diamond. Add to this an IS to check for leakage and symmetry issues, and I don't see why it should be so hard to identify the "good" 60/60's in online shopping situations.

 

[Dancing Fire]

I am certain that the majority of folks here will continue to favor the before established “Ideal” proportions, but are we missing on some major coverage for ignoring 60:60 stones? Should we leave them in the past, or are we missing on some untapped 60:60 Ideal Cut diamond potential?

Congrats, that is a beautiful looking 60/60 stone. I had a "flat top 60/60" recut into ideal proportions. There is nothing wrong with buying a 60/60 stone with good crown height like yours... just try to avoid the flat top ones....
https://www.pricescope.com/communit...t-after-the-recut-by-infinity-diamonds.24501/

 

[Karl_K]

"having virtual facets that turn on and off as the diamond moves w.r.t. the light source").

diamond moves viewer moves light moves not just diamond movement.
It is also relative to the viewer.
3 people viewing the same diamond get a different view with virtual facets and lighting environment that does not exist to the other 2 people.

 

[diamondseeker2006]

Here's a great page I found comparing fire with a superideal cut and a 60/60 stone that should be of interest in this discussion.

https://www.whiteflash.com/about-diamonds/diamond-education/diamond-fire-1568.htm

 

[pyramid]

Reading with interest to see what some of the experts such as Garry Holloway, Rockdiamond and others will say.

I recall years ago, talk about high crown angles with smaller tables could be more susceptible to chipping or damage on the top of the crown. We never see this being discussed now.

I thought Lazar Kaplan were the original ideal cut diamonds.

Are internet ideal cut just to take customers away from jewellers stores by selling a new better technogically proven product? A copy of the Japanese star cut. A lot of the research over the years has been ongoing, the ags even changed their ideal cut status making lots of peoples stones become ags1. Now we are discussing scintillation and it is not proven. In my opinion then ideal cut does not really exist now it is just a trial to see what we can find out. When I see old designs from Cartier or Tiffany online I think they are far too busy and not what I would call beautiful but some will think they are, so beauty is in the eye of the beholder I would say for diamonds too. Some prefer warmer, some prefer sharper cooler, so why would we all prefer the same cut look. Anyway is it not said in marketing that every diamond is unique so how can they be cut to look the same? Maybe DeBeers can answer that one?

 

[Karl_K]

Fire is extremely complex and the number 1 factor is lighting.
Number 2 is lighting as is the top 5.
In lighting highly conductive to fire a diamond that is considered poorly cut in other lighting may have the "best" fire.
Keep in mind that "Ideal" cut RBs are not necessarily the best at any one thing.
They were found to look good across a wide range of lighting and viewing distances.
Frankly in my opinion fire and scintillation grading will never be totally solved the variables are way to high.

 

[Rockdiamond]

HI Everyone!!
I just flew back from Mexico, and boy my arms are tired!!
Seriously- thank you SimoneDi for starting this wonderful discussion.
I'll be a bit short of time today due to a tidal wave of emails from the past two weeks- but starting out- the subject of fire.
TOTAL red herring.
Actual facet size has the greatest bearing on the ability to produce perceivable fire events.
So a 3ct will have greater potential than a one carat- even if cut to the same proporiopns.
So any discussion of fire without considering the size of the diamond is missing the point.
Plus Karls point about lighting.

 

[Rockdiamond]

Reading with interest to see what some of the experts such as Garry Holloway, Rockdiamond and others will say.

I recall years ago, talk about high crown angles with smaller tables could be more susceptible to chipping or damage on the top of the crown. We never see this being discussed now.

I thought Lazar Kaplan were the original ideal cut diamonds.

Are internet ideal cut just to take customers away from jewellers stores by selling a new better technogically proven product? A copy of the Japanese star cut. A lot of the research over the years has been ongoing, the ags even changed their ideal cut status making lots of peoples stones become ags1. Now we are discussing scintillation and it is not proven. In my opinion then ideal cut does not really exist now it is just a trial to see what we can find out. When I see old designs from Cartier or Tiffany online I think they are far too busy and not what I would call beautiful but some will think they are, so beauty is in the eye of the beholder I would say for diamonds too. Some prefer warmer, some prefer sharper cooler, so why would we all prefer the same cut look. Anyway is it not said in marketing that every diamond is unique so how can they be cut to look the same? Maybe DeBeers can answer that one?

O M G
This keeps me from emails for a few more moments.
What a great post!!!
The bold part, yes- true.

The underlined part!!!!!
YES YES YES YES
Not exactly how I'd put it. I do not criticize other sellers for using these tools- but this has been a crux of the discussion for many years. And I've been roundly criticized for questioning the tools, such as ASET.
The old story of a man looking under a streetlight on a dark night.
Searching for something on the ground.
Another man sees him and wants to help.
"What are you searching for?"
"I lost my keys"
So the second man starts to help.
After while, the second guy asks
"Are you sure you dropped them here?"
"No- I dropped them way over there, but the light is better here?

Basically, the theory here has been- since we don't know how to judge scintillation, let's look where the light is.
We can assess contrast and brightness, so let's just use that metric.

And Pyramid- your tag line.....
PRICELESS!!!!

 

[drk14]

diamond moves viewer moves light moves not just diamond movement.
It is also relative to the viewer.

@Karl_K , I agree, thanks for the correction. And I also concede that lighting is an important (and difficult to control) variable in evaluating fire.

Nonetheless, do you (or anybody else) disagree with my main point that it is possible to identify 60/60 stones that have good scintillation properties by evaluating vf "liveliness" in diffusely lit videos?

 

[Karl_K]

Weird if the ideal cut is an internet conspiracy then why did I see a commercial last night for a local b&m advertising ideal cut diamonds?

 

[drk14]

Here's a great page I found comparing fire with a superideal cut and a 60/60 stone that should be of interest in this discussion.

https://www.whiteflash.com/about-diamonds/diamond-education/diamond-fire-1568.htm

Interesting, but to be clear, the comparison is to a 60/60 with relatively shallow crown (31.5) and steep pavilion (41.4), which has HCA=3.

 

[Karl_K]

@Karl_K , I agree, thanks for the correction. And I also concede that lighting is an important (and difficult to control) variable in evaluating fire.

Nonetheless, do you (or anybody else) disagree with my main point that it is possible to identify 60/60 stones that have good scintillation properties by evaluating vf "liveliness" in diffusely lit videos?

Yes and no.
I disagree because video even 3d video does not closely enough correlate to human vision.
I agree that if a diamond looks dead in video with lazy scintillation it will likely look that way in person.
So video is useful, but don't think that the diamond will look exactly like that in person.

 

[drk14]

I agree that if a diamond looks dead in video with lazy scintillation it will likely look that way in person.

Can you describe a scenario in which the converse is false? That is to say, if a diamond appears to be lively in the video (with scintillation that is widespread and "rapid/crisp" -- or whatever the word describing the opposite of "lazy" is), are there conditions under which this diamond will be "dead" IRL?