How much more sparkle will I see with a top cut?

[miraj]

I went to a B&M jeweler to look at the brightness, scintillation, and fire of a few GIA Excellent cut and Very Good cut RB stones in the 2ct range. They tended to be deeper cut than the strictest standards, but not terrible either - they were around 62.8%. The pavilion and crown angles were not within the top cut range, but they weren't terrible either.

I could detect a slight difference in the sparkle between the Ex stones and VG stones under extreme lighting (100's of LED lights from above). I couldn't tell a difference when I moved away into pretty flat lighting of those long ceiling fluorescent bulbs.

How much more sparkle would I see in a top-cut (like a WF ACA, JA H&A, BGD Signature, etc)? Will the increase between a typical GIA Excellent and a top-cut be a similar amount of improvement between GIA VG and GIA Excellent?

I am a huge fan of the PS "cut is king" approach, but I want to go beyond the ASET results and understand what peoples' eyes detect.

 

[marcy]

If you have different cuts of diamonds side by side you will probably notice a difference. I would try to find a place where you can compare an AGS0 with a GIA XXX and then also some diamonds with a good and very good rating. Don't have them tell you which is which; let your eyes be the judge. I think many diamonds will perform superbly in certain lighting (especially the ones jewelry stores tend to have) but IMO the ideal cut diamonds will perform better in more lighting situations.

 

[miraj]

I'm surprised that I didn't hear an outcry of "top cut will look tremendously better!" on PS.

I'm finding it hard to justify the extra cost associated with top-cuts. I can find a GIA XXX 2ct for 20% less than a top cut. Will it sparkle 1/5 less?

 

[marymm]

Okay, I'll bite... yes, IMO top cuts are "better" in all the ways measurable -

BUT... if you are comparing a well-cut diamond to a top-cut diamond, side by side, you (meaning an individual intent on buying a diamond) may well prefer the well-cut diamond for economic reasons as well as aesthetic reasons.

In terms of economics, well-cut stones are priced less than ideal-cut/super-ideal-cut diamonds.

In terms of aesthetics, if your (the buyer's) eyes cannot see a perceptible difference in performance, or if you can see the difference but do not assign a higher value to the ideal-cut diamond, then buy the well-cut diamond.

Because vision acuity and value judgments vary from person to person, none of us can tell you whether and/or how much more sparkle you (or anyone) might see in a comparison of a well-cut diamond and an ideal-cut diamond.

I can tell you that I've bought GIA XXX and super-ideal-cut MRBs, and the super-ideal-cut diamonds are well worth the price *to me* as I see a far superior performance out of the super-ideal-cut diamonds - your mileage may vary however.

(Note: if you are only examining/comparing diamonds under a jeweler's lights, you may want to try comparing the diamonds by lowering them underneath the jewelry counters and away from overhead lights; perhaps your jeweler would also be amenable to taking a pair of diamonds outside or over to a natural-daylight window environment -- by varying the lighting conditions, you will get a truer read of the diamonds' comparative performances. And, keep in mind jeweler's lights can make frozen spit look delightful.)

 

[pfunk]

IMO, not much. From a visual standpoint, not worth the extra money. Suppliers of "top cuts" sometimes offer other value adding policies when you purchase the top cut stones (trade in, buy back, etc). But from a strictly visual standpoint, in the eyes of an average consumer, the differences are going to be hard to see when comparing superideal to ideal cut or GIA excellent cut with ideal or near ideal proportions. Comes down to a personal decision as to whether you want the "top" cut and the policies that come with it, or if that money would be better spent on something else. One thing is absolutely certain, you don't need "top" cut to get a gorgeous diamond.

 

[mark229]

Thank you for this discussion, it is extremely helpful to a novices like me who are trying to understand the science better.

I'm in a similar dilemma myself as I'm trying to choose based on my budget between two 2 ct round diamonds: one with an ideal cut, G color, VVS2 clarity and strong fluorescence (http://www.jamesallen.com/loose-diamonds/round-cut/2.10-carat-g-color-vvs2-clarity-excellent-cut-sku-402438
) and a blue nile signature ideal cut with H color, VS2 clarity and no fluorescence (http://www.bluenile.com/diamond-details/LD06101173).

Does the better cut and lack of fluorescence make up for the lower color and clarity or am I overpaying for the cut and should stick to the former?

 

[Jambalaya]

In my own opinion, which is subjective of course, I do see a difference between an average GIA XXX and a super-ideal cut. To me, I've noticed that I can see the sparkle from further away when testing that in a mirror, and they just throw more fire and sparkle in general when I look at them. I can see it. I also think that the superior sparkle makes the stone look bigger. But, I have a friend I was shopping with, and there were two diamonds. One was very average and not that sparkly at all, and the other was a Hearts on Fire disco-ball. She said she couldn't see any difference. I was all like, huh?? How can you not see that??

So I think it really depends on the person. Also there is a wide range of GIA XXX. Some are very poorly cut, scoring very badly on the Holloway Cut Advisor, and some just miss super-ideal dimensions, and some are 60/60 stones which don't qualify for super-ideal status but which can be really sparkly. (You can research 60/60 on this site if you're not familiar.)

So in short it's very subjective, given the range of XXX. I believe I can see a difference between a really good XXX and super-ideal but I'm very picky!

If you have an eye on economics, maybe forget about super-ideal - because you do pay quite a premium for that - and choose the sparkliest GIA XXX that you can find in person. Find one you adore, judging it with your eyes. Then you will have a diamond that you love, without paying the mark-up for a super-ideal.

 

[Texas Leaguer]

Because of economics most people do not buy D FL Ideal cuts. But many see value in a D color even though F is colorless, and even more see value in purities five or six grades higher than "eye clean". Meanwhile, most people agree that cut quality is an area where you should be least willing to compromise. Design and craftsmanship of the cut is critical to diamond beauty. In a different world, all diamonds would be precision cut by default. But the question today becomes, how good does cut quality need to be? As you bump up against the limits of what is possible in terms of faceting precision, the visual differences clearly become less obvious.

But if you think of a diamond as a miniature three dimensional sculpture made of mirrors, and diamond craftsmanship as an art form, it becomes much easier to understand why some people insist on top precision.

Diamonds that have deficits in proportioning or optical precision do not deliver on their full potential. The extent to which that is important to a buyer is a matter of personal taste - much like the ability to hear and appreciate the subtleties of high end audio equipment or sense the subtle flavors and textures of fine wine. But there is also value in knowing that a diamond has been master crafted with the sole purpose of maximizing light performance and beauty.

The fact that a diamond which is not precision cut can still be pretty does not diminish the value of a diamond that is crafted to a level of cut quality that conveys it's full potential for beauty. It's a matter of personal preference and they way in which you are approaching the question.

 

[Texas Leaguer]

Thank you for this discussion, it is extremely helpful to a novices like me who are trying to understand the science better.

I'm in a similar dilemma myself as I'm trying to choose based on my budget between two 2 ct round diamonds: one with an ideal cut, G color, VVS2 clarity and strong fluorescence (http://www.jamesallen.com/loose-diamonds/round-cut/2.10-carat-g-color-vvs2-clarity-excellent-cut-sku-402438
) and a blue nile signature ideal cut with H color, VS2 clarity and no fluorescence (http://www.bluenile.com/diamond-details/LD06101173).

Does the better cut and lack of fluorescence make up for the lower color and clarity or am I overpaying for the cut and should stick to the former?

As a member of the trade I cannot comment on another vendor's diamonds, but if you want to explore the impact on price and value of fluorescence you can start with the overview article here:
https://www.pricescope.com/wiki/diamonds/diamond-flourescence

 

[John P]

In my own opinion, which is subjective of course, I do see a difference between an average GIA XXX and a super-ideal cut. To me, I've noticed that I can see the sparkle from further away when testing that in a mirror, and they just throw more fire and sparkle in general when I look at them. I can see it. I also think that the superior sparkle makes the stone look bigger. But, I have a friend I was shopping with, and there were two diamonds. One was very average and not that sparkly at all, and the other was a Hearts on Fire disco-ball. She said she couldn't see any difference. I was all like, huh?? How can you not see that??

So I think it really depends on the person. Also there is a wide range of GIA XXX. Some are very poorly cut, scoring very badly on the Holloway Cut Advisor, and some just miss super-ideal dimensions, and some are 60/60 stones which don't qualify for super-ideal status but which can be really sparkly. (You can research 60/60 on this site if you're not familiar.)

So in short it's very subjective, given the range of XXX. I believe I can see a difference between a really good XXX and super-ideal but I'm very picky!

If you have an eye on economics, maybe forget about super-ideal - because you do pay quite a premium for that - and choose the sparkliest GIA XXX that you can find in person. Find one you adore, judging it with your eyes. Then you will have a diamond that you love, without paying the mark-up for a super-ideal.

This is a great overview.

Unlike color and clarity, which remain static, a diamond's brightness, life and sparkle behave differently in different lighting. Our world presents an infinite panorama of illumination scenarios the wearer will find him or herself in, hour after hour, day after day. Not simply a jewelry counter, where any diamond looks good.

Just as importantly, what you see/value are subject to considerations which vary from person to person.

Personal Perception: High performance nuances are vividly seen by some people but completely lost on others. Do you have perfect pitch - are you tone-deaf or somewhere in-between? How is your wine palate? The physiology of individual eyesight varies. One person may easily detect more in a diamond’s performance qualities over a broad range of illumination scenarios than another person.

Length of Exposure: Wine palates become educated. Singing in-tune can be taught (It really can I promise...my parents were career voice instructors). Cut perception evolves with exposure. Karl_K (aka Strmrdr) advocates a 2-week rule, steadily making observations in familiar places. Most e-sellers of top cut-quality offer a return-period of at least a week, so that time can be spent developing your diamond palate and - if permitted - making local comparisons to other options.

Taste: Not everyone even wants a round brilliant. Some fancy shapes have configurations that won't sparkle like mad, but that may be secondary to the geometric aesthetic desired. A heart-shape is such an example. Also, step cuts like emeralds have a completely different charm than brilliants, so sparkle may not be a top priority. Vive la difference.

I feel the best way to judge diamonds is by making comparisons in person, through different lighting scenarios: Our world has an infinite panorama of illumination situations - and a diamond's cut specifics dictate how much it will give back to the viewer from situation to situation. A side by side comparison of 2-3 diamonds through a tour of Spotlighting, Natural Lighting, Diffused Lighting, Low Lighting and Filtered Lighting is usually illuminating for anyone as a practical exercise. And, such a tour permits conclusions in accordance to the actual viewer's taste, nuance-perception and maturity of palate. No one else's. In that spirit - and not just for rounds but for all things diamond - there are no "wrong" conclusions, only personal ones.

 

[Rockdiamond]

Very interesting discussion!

By no means is a GIA graded VG cut grade stone going to have a standard differential as compared to a GIA EX. As was mentioned, there's a range within each cut grade. The net result is that some GIA VG cut graded diamonds would have light performance that is preferable ( or considered "better" by PS standards) to other GIA graded EX cut grade stones.
IMO, this imparts certain VG cut grade stones with tremendous added value.

But most interesting to me is how the question is phrased: How much more sparkle will I see?
This implies we can accurately measure "sparkle", which we can't.
For one thing, there's no agreed upon, clinical definition of "sparkle"
This means two people will look at the same two diamonds and come to different "sparkle" conclusions.

Personally, I am very happy that not all diamonds are "precision cut"- because that would be soooo boring

 

[denverappraiser]

Every day I wear a super-ideal diamond. 0.96/K/VVS2. In order to avoid the perception of bias, I won't admit who made it but, as I'm sure you can all imagine, I did not choose it randomly (I got married in 2012). I am, umm, fairly particular about this sort of thing.

People look at it a LOT. They're floored when I tell them it's a K color because they've seen things online and expected that this would reduce the sparkle/brilliance/fire or something other than what it is. It's a little fireball. Yes, I keep it clean, and yes, I have good lights, but people routinely want to compare it to other stones and consistently inexpert viewers say it's the best looking diamond they've ever seen. Maybe they're just sucking up to me, which people do from time to time, and maybe it's just that they're not used to seeing men with diamonds, but I get it enough that I think it's fair to say that yes, people can tell the difference. I certainly can.

 

[Texas Leaguer]

Very interesting discussion!

By no means is a GIA graded VG cut grade stone going to have a standard differential as compared to a GIA EX. As was mentioned, there's a range within each cut grade. The net result is that some GIA VG cut graded diamonds would have light performance that is preferable ( or considered "better" by PS standards) to other GIA graded EX cut grade stones.
IMO, this imparts certain VG cut grade stones with tremendous added value.

But most interesting to me is how the question is phrased: How much more sparkle will I see?
This implies we can accurately measure "sparkle", which we can't.
For one thing, there's no agreed upon, clinical definition of "sparkle"
This means two people will look at the same two diamonds and come to different "sparkle" conclusions.

Personally, I am very happy that not all diamonds are "precision cut"- because that would be soooo boring

While scintillation as an attribute is not specifically graded because facet designs and tastes vary, the components of "sparkle" are measureable; brightness, contrast, leakage, and dispersion. And optical precision that can be assessed by reflector images and tools such as VPA.

 

[Rockdiamond]

I agree we can measure cutting precision however sparkle is made up, by your definition (Bryan), of brightness contrast leakage and dispersion. How much percentage of each do we need for sparkle? How much percentage does one diamond posses more sparkle than another?
Would it matter under which lighting conditions one is viewing the diamond?
As you point out, these are elements of taste and perception therefore cannot be accurately converted to meaningful calibrated measurements such as you might find on a ruler

 

[miraj]

Many thanks for the replies, including some heavy-hitters of the forum weighing in. (I am a mere layman just trying to get to the truth by challenging ideas, so I apologize for any arrogance in my responses.)

I believe I can see a difference between a really good XXX and super-ideal but I'm very picky!

Jambalaya: It sounds to me like that visual difference is just barely discernible. Are you willing to pay more for that? How much more?

(When I look at GIA XXX, I try to go with the angles and percentages that result in good HCA scores, so hopefully I'm only considering "really good".)

choose the sparkliest GIA XXX that you can find in person

Jambalaya: Finding a very sparkly diamond is my quest. But to control the variables, you have to have all of the candidate diamonds in one place, which has been not feasible for me since I am considering them from multiple sources (online and B&M).

if you think of ... diamond craftsmanship as an art form, it becomes much easier to understand why some people insist on top precision.

Texas Leaguer: What I think you are saying is that paying more for the rarity of super-ideal-cut is comparable to paying more for the rarity of colorless and flawless diamonds. The beauty difference between a D vs F is negligible (in visual terms, not mental) but a D is much more rare, so that rarity drives a higher price. Similarly, the rarity of super-ideal-cut drives a higher price.

Paying a premium for rarity is not what I want to do. As a guy seeking max-bling-for-the-buck, I only want to pay more for more sparkle.

So that begs the questions: At what point is the cut "good enough" such that improvement on the cut quality shows negligible "sparkle" improvement? And at what point does improvement on the cut quality drive up the price due to rarity rather than "sparkle"?

The physiology of individual eyesight varies.

This implies we can accurately measure "sparkle", which we can't.

John Pollard: The various questions I pose in this and previous comments are easily answered as "it's subjective", and I appreciate your explanation breaking that down further. But... (see next response)

Rockdiamond: "Sparkle" can sort-of be described as "light performance" but I think that is too technical because it doesn't include the human factor. In the end I'm trying to get something that makes (1) my significant other say "wow" and (2) the highest number people that she shows it to say "wow" (or those who just see it from 10 tables away in a restaurant). So I believe that can be achieved somewhat scientifically by aggregating opinions of a sample of people, just as Tolkowsky did. The connoisseurs may disagree with the group survey results but impressing the diamond elite is not most people's objective. That is what I am generally referring to by "sparkle", which can be measured or at least understood through aggregating human opinion.

 

[Texas Leaguer]

Many thanks for the replies, including some heavy-hitters of the forum weighing in. (I am a mere layman just trying to get to the truth by challenging ideas, so I apologize for any arrogance in my responses.)

if you think of ... diamond craftsmanship as an art form, it becomes much easier to understand why some people insist on top precision.

Texas Leaguer: What I think you are saying is that paying more for the rarity of super-ideal-cut is comparable to paying more for the rarity of colorless and flawless diamonds. The beauty difference between a D vs F is negligible (in visual terms, not mental) but a D is much more rare, so that rarity drives a higher price. Similarly, the rarity of super-ideal-cut drives a higher price.

Paying a premium for rarity is not what I want to do. As a guy seeking max-bling-for-the-buck, I only want to pay more for more sparkle.

So that begs the questions: At what point is the cut "good enough" such that improvement on the cut quality shows negligible "sparkle" improvement? And at what point does improvement on the cut quality drive up the price due to rarity rather than "sparkle"?

Miraj,
The thought process you are going through is worthwhile. It is not a one size fits all kind of proposition, so by gathering the information and opinions you will be able to determine where you feel the returns start to diminish for you.

To clarify, I was not saying that the value of top craftsman was simply rarity. In my opinion and in the opinion of many experts and knowlegeable consumers, cut quality makes so much difference that there is real value in holding out for the very best. My point about clarity grades was to indicate that as critical as cut is to actual performance, there are a series of grades that make virtually no difference to performance yet they entail price premiums far greater than going from a good GIA EX to a super ideal.

Here is another thing to keep in mind. There are those that feel that a well cut diamond is "good enough" and most observers will think its pretty. And it's hard to argue with them. But the question is not so much what you are getting, but what you are giving up. For instance, lack of precision can alter the number, size and distribution of vitual facets that the design is intended to produce. This can change the frequency and size of sparkles and the probability of seeing fire (colored sparkles). So a stone that lacks precision may look just fine in many lighting scenarios. You never really know under what circumstances the dropoff will occur and it's not something that is obvious. But you can be sure that it will occur.

 

[kenny]

You will see 24.113% more sparkle in a top cut.

 

[kenny]

And at what point does improvement on the cut quality drive up the price due to rarity rather than "sparkle"?

At point 17.245.

 

[kenny]

I'm surprised that I didn't hear an outcry of "top cut will look tremendously better!" on PS.

I'm finding it hard to justify the extra cost associated with top-cuts. I can find a GIA XXX 2ct for 20% less than a top cut. Will it sparkle 1/5 less?

Top cut will look tremendously better.

Yes, well actually 19.578% less.

 

[kenny]

Top cut cost more because it's more work, is done by more expensive people in smaller quantities, and usually grinds away and wastes more of the rough diamond material.
Sometimes it means getting only one cut diamond out of a given piece of rough, instead of two.

There's also economy of scale.
Quickly producing a zillion poorly-cut diamonds is cheaper-per-diamond than an artisan laboring over one superbly-cut diamond.

IMO, top cut cost more not so much because it is more rare in the nature-sense, like D-color is more rare.
It costs more to deliver.

 

[Rockdiamond]

Many thanks for the replies, including some heavy-hitters of the forum weighing in. (I am a mere layman just trying to get to the truth by challenging ideas, so I apologize for any arrogance in my responses.)

I believe I can see a difference between a really good XXX and super-ideal but I'm very picky!

Jambalaya: It sounds to me like that visual difference is just barely discernible. Are you willing to pay more for that? How much more?

(When I look at GIA XXX, I try to go with the angles and percentages that result in good HCA scores, so hopefully I'm only considering "really good".)

choose the sparkliest GIA XXX that you can find in person

Jambalaya: Finding a very sparkly diamond is my quest. But to control the variables, you have to have all of the candidate diamonds in one place, which has been not feasible for me since I am considering them from multiple sources (online and B&M).

if you think of ... diamond craftsmanship as an art form, it becomes much easier to understand why some people insist on top precision.

Texas Leaguer: What I think you are saying is that paying more for the rarity of super-ideal-cut is comparable to paying more for the rarity of colorless and flawless diamonds. The beauty difference between a D vs F is negligible (in visual terms, not mental) but a D is much more rare, so that rarity drives a higher price. Similarly, the rarity of super-ideal-cut drives a higher price.

Paying a premium for rarity is not what I want to do. As a guy seeking max-bling-for-the-buck, I only want to pay more for more sparkle.

So that begs the questions: At what point is the cut "good enough" such that improvement on the cut quality shows negligible "sparkle" improvement? And at what point does improvement on the cut quality drive up the price due to rarity rather than "sparkle"?

The physiology of individual eyesight varies.

This implies we can accurately measure "sparkle", which we can't.

John Pollard: The various questions I pose in this and previous comments are easily answered as "it's subjective", and I appreciate your explanation breaking that down further. But... (see next response)

Rockdiamond: "Sparkle" can sort-of be described as "light performance" but I think that is too technical because it doesn't include the human factor. In the end I'm trying to get something that makes (1) my significant other say "wow" and (2) the highest number people that she shows it to say "wow" (or those who just see it from 10 tables away in a restaurant). So I believe that can be achieved somewhat scientifically by aggregating opinions of a sample of people, just as Tolkowsky did. The connoisseurs may disagree with the group survey results but impressing the diamond elite is not most people's objective. That is what I am generally referring to by "sparkle", which can be measured or at least understood through aggregating human opinion.

We are in agreement on this point, and the system you're describing is GIA's round cut grade.
There are ways to measure different elements of how light moves through a diamond- interpreting those results is where human perception and taste comes into play.
AS you point out, we can measure people's opinions- which were incorporated into GIA's cut grade-'
GIA's system get criticized here due to the fact that certain combinations that the EX grade allows are not considered to be "Excellent" by many experts- and I can see that point.

I also find that many VG cut grade stones will perform every bit as well as an AGSL 000 in many important regards.
Using the color/clarity analogy- if an SI2 is totally eye clean, with no grade setting cloud issues, is it not virtually identical to an internally flawless to the naked eye?
If a really well cut stone has issues that you needed a microscope to detect, is it not also visually identical?
I love owning both types of stones- and can relate to both lines of reasoning. SI2's are not for everyone. VG ct grade diamonds are not for everyone- but either might do the job you're asking.
Based on your comments, I think you would be well served looking at more diamonds first hand.
Statistically, it's likely that the EX cut grade stones you saw were visibly better cut- but it's just not true in every case.

If a you're a consumer wants to get the very best cut from a scientific standpoint, go for super ideal. Super Ideal is safer for consumers who are buying online, in many cases- because they can't compare first hand.
If a consumer is shopping value and size in stores, I would recommend looking at EX, and or VG cut graded GIA diamonds, or AGSL1 cut grade stones, if you can find them at a discount over 0 cut grade stones. Try to find some closer to 60% depth ( I was raised on well cut 60/60 diamonds).

If you were comparing two RBC diamonds, and preferred the VG cut grade, you should have no fear that it will behave differently than an EX cut grade over the long term.

 

[Krackr]

I wonder if ..Denverappraiser ...would be so kind as to give us the proportions etc for his .96carat diomond he referenced to

 

[Jambalaya]

Many thanks for the replies, including some heavy-hitters of the forum weighing in. (I am a mere layman just trying to get to the truth by challenging ideas, so I apologize for any arrogance in my responses.)

I believe I can see a difference between a really good XXX and super-ideal but I'm very picky!

Jambalaya: It sounds to me like that visual difference is just barely discernible. Are you willing to pay more for that? How much more?

(When I look at GIA XXX, I try to go with the angles and percentages that result in good HCA scores, so hopefully I'm only considering "really good".)

choose the sparkliest GIA XXX that you can find in person

Jambalaya: Finding a very sparkly diamond is my quest. But to control the variables, you have to have all of the candidate diamonds in one place, which has been not feasible for me since I am considering them from multiple sources (online and B&M).

No, to me the difference is not just barely discernible. As I said above, I can see it, and I provided examples of the extra that I see, like the mirror further away (see above). I pay about an extra twenty per cent and for me it's worth it because I can see the difference. But as I explained above, I am aware that not everyone can. And since it's difficult to compare diamonds from different sources, and since you very much question the value of the premium for a super-ideal, why not just pick a diamond that you love in person. Or, you could always order a super-ideal in a plain setting from online and take it with you to compare.

 

[egemnoel]

Two good videos, that shows the difference.

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

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

 

[Texas Leaguer]

Miraj,
You may also want to read through this somewhat older thread that has recently been bumped. It deals with similar questions:
[URL='https://www.pricescope.com/community/threads/show-me-examples-of-good-numbers-poor-idealscope.210997/page-4']https://www.pricescope.com/community/threads/show-me-examples-of-good-numbers-poor-idealscope.210997/page-4[/URL]

 

[denverappraiser]

I wonder if ..Denverappraiser ...would be so kind as to give us the proportions etc for his .96 carat diamond he referenced to

I’m hesitant to answer this. I do know, of course, but I don’t want to contribute to the idea that parsing the numbers is an end all shopping strategy. You’ll notice that I never participate in those threads. I bought a branded stone, which is not a strategy that’s particularly well regarded here. The theory goes that they cost extra and deliver no value beyond what you can do yourself by filtering the numbers. I don’t agree with this, although I certainly understand where it’s coming from and I most definitely DID look at the numbers and I will say they fall in the standard PS recommended range. It is both GIAxxx and AGS000. I bought a brand, and I paid extra to get it. I pay extra to go to good restaurants occasionally too.

What I got for this added value is a little harder to pin down.

The angles interrelate in some important ways that are not well represented in the GIA cut scale and the GIA rounding covers more sins than I want to see excluded. The AGS approach is considerably better but it doesn’t cover everything either. Subtle issues with polish and symmetry are important to me. It’s fundamental to the difference between a lab grading thousands of stones and an artist who produces one that they’re willing to attach their name to. The lab has to apply a range of acceptable values while the artist has to sign it. It’s literally carved in stone. (OK, it written on the girdle in a microscopic font that takes a microscope to read but you get the point). These are not the same thing. I chose the later.

 

[Jambalaya]

Fascinating videos, egem!

In the second one, near the end, when the two diamonds are compared under Intense Shop Lighting, the diamond on the left very clearly has superior performance, to my eyes.

 

[Texas Leaguer]

Fascinating videos, egem!

In the second one, near the end, when the two diamonds are compared under Intense Shop Lighting, the diamond on the left very clearly has superior performance, to my eyes.

It also illustrates the limitations of HCA scores. In particular it demonstrates how a lower score under 2 does not necessarily equate to better performance. As Garry Holloway makes clear HCA is a rejection tool, not a selection tool. Often we see people trying to do too much with that tool, usually in the abscence of other diagnostics such as LP images.

 

[Krackr]

Neil...I respect your reasoning for your answer to my request.However you did shed some light on matters of interest thx.

 

[pfunk]

Fascinating videos, egem!

In the second one, near the end, when the two diamonds are compared under Intense Shop Lighting, the diamond on the left very clearly has superior performance, to my eyes.

It also illustrates the limitations of HCA scores. In particular it demonstrates how a lower score under 2 does not necessarily equate to better performance. As Garry Holloway makes clear HCA is a rejection tool, not a selection tool. Often we see people trying to do too much with that tool, usually in the abscence of other diagnostics such as LP images.

You guys are assuming these two stones are given the same lighting and that they are both equally clean. I wouldn't put too much stock in a video produced by that the company that is trying to sell you on superideal stones being better, nor would I assume their representation is what you should expect to see in most cases in real life viewing.