shape
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Please help me choose between these two diamonds

Cherub23

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I input the specs of each diamond (both 2 carat D colour SI1) into the HCA and got scores of 1.3 and 1.6 which are both great.

I've decided to call the 1.3 the "Average-Sized All-Rounder" - she is 8.06mm with a depth of 61.7% and crown angle of 34.5, pavilion 40.8

The 1.6 is "The Very Big but Slightly Shallow" - she is 8.2mm but depth of 58.8% and crown angle of just 32.3, pavilion of 40.1

Both are SI1, nothing visible to naked eye, about equal in terms of placement of inclusions.

The names I've given each diamond capture the pros and cons. I have large fingers (size 7.5) so the bigger the better. But I really really love a bright, crisp sparkle under all lights, and I'm worried Very Big but Slightly Shallow won't deliver as much as Average-Sized All-Rounder. Any opinions are welcome. Thanks so much!

Screen Shot 2021-04-20 at 10.32.22 am.png
Screen Shot 2021-04-20 at 10.32.27 am.png
 

Txborn79

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297
I input the specs of each diamond (both 2 carat D colour SI1) into the HCA and got scores of 1.3 and 1.6 which are both great.

I've decided to call the 1.3 the "Average-Sized All-Rounder" - she is 8.06mm with a depth of 61.7% and crown angle of 34.5, pavilion 40.8

The 1.6 is "The Very Big but Slightly Shallow" - she is 8.2mm but depth of 58.8% and crown angle of just 32.3, pavilion of 40.1

Both are SI1, nothing visible to naked eye, about equal in terms of placement of inclusions.

The names I've given each diamond capture the pros and cons. I have large fingers (size 7.5) so the bigger the better. But I really really love a bright, crisp sparkle under all lights, and I'm worried Very Big but Slightly Shallow won't deliver as much as Average-Sized All-Rounder. Any opinions are welcome. Thanks so much!

Screen Shot 2021-04-20 at 10.32.22 am.png
Screen Shot 2021-04-20 at 10.32.27 am.png

Going by just the numbers, I’d choose the first one. Do you have any pictures or videos?
 

lovedogs

Super_Ideal_Rock
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We aren't supposed to talk about lab stones on this forum, but I don't like the 2nd option at all. The 1st one is much nicer IMHO
 

Cherub23

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We aren't supposed to talk about lab stones on this forum, but I don't like the 2nd option at all. The 1st one is much nicer IMHO

Thanks so much for your advice! I think I'll settle with that one, then. Appreciate your help!
 

sledge

Ideal_Rock
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Option 1 has near perfect Tolk proportions. I would advise advanced images if you can get them. If not be familiar with the return policy and buy your own scopes to evaluate in your home.

More concerning to me is the HCA score for stone 2. This seems like a very generous score. I would like @Garry H (Cut Nut) and also @Karl_K to weigh in on the proportions of stone 2.

Also I would love to see some of the fancy pants images and anticipated score ratings that software can produce that I can’t get my hands on.
 

sledge

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I understand these are nothing more than a cross-reference to outdated AGS charts, but throwing these out for reference as well. The chart doesn't allow for 56.5 table, so I've included both 56 & 57. Also, crown is rounded to 32.5, but using the graphical data in the chart we can see we would need to move a smidge to the left to land perfectly at 32.3.

Again, not using this as empirical evidence. Just saying my own understanding of c/p relationships doesn't jive with what I'm seeing in that HCA score and these charts seem to support this as well, even if they are very antique in comparison to advanced software.

For clarity, my question is for the sake of education -- not to bash or condemn or make any similar type negative statements or implications.


Screen Shot 2021-04-20 at 1.15.31 AM.png


Screen Shot 2021-04-20 at 1.16.27 AM.png
 

Garry H (Cut Nut)

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Interesting combo.
My Fire estimation 21 years ago was clearly wrong on this extreme set of proportions.
And brilliance light return in a ring would be bad.
But in a pendant or earrings it would be stunning.
Here is a video - seen from a meter or 3 feet away the stone would be very very bright.

https://youtu.be/scq_4BhTmZQ

1618959731824.png
 

Avatar345

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Garry H (Cut Nut)

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At first I thought to myself - those renderings all look the same...?

And then I noticed, the first and second videos are in fact the same! (as per the links)
Those are supposed to be different right? :)

You are right - more speed less haste!
Here is the correct links.
With your permission I asked Ella the lovely Mod to change my post and delete yours )if that is OK)

You will note as mentioned earlier - a lot more fire in the Tolkowsky, but more contrast flashing taking over and looking too dark almost all the time in the extremely shallow stone in a ring viewing distance.
 

Avatar345

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You are right - more speed less haste!
Here is the correct links.
With your permission I asked Ella the lovely Mod to change my post and delete yours )if that is OK)

You will note as mentioned earlier - a lot more fire in the Tolkowsky, but more contrast flashing taking over and looking too dark almost all the time in the extremely shallow stone in a ring viewing distance.

Not to thread hijack but Garry while you're here (and the mod can separate this out later as well certainly), but wanted to get your thoughts on IdealScope images...

Here's one from 2014, reflective of sort of what you see normally when a scope is performed... that range of red tones, etc

Here's one from 2019 also BGD, and here's one from 2021

With the tone in the reds here vs the older scope, is that attributable to anything in particular? The reds just seem hyper-saturated, and I don't know whether that's a reflection of the truly superior light performance, or whether the tone is shifted for further visual impact? Or... I guess, maybe it's as simple as the color used in the IdealScope has changed slightly over the years? I just want to try and be as close to apples-to-apples in my understanding as possible when looking at these images across different sites and figured no one would better be equipped to answer this than you :)
 

sledge

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Thanks for the additional info Garry. I didn’t realize you developed the HCA 21 years ago. I know you recently updated to include the “looks like” size component.

Have you updated any of the logic for the various HCA ratings, or do you foresee doing that anytime in the future now that you have more technology available?

For instance it seems this stone may yield a different score for ring vs pendant or earrings. Typically I thought 0-1 was better for the latter, whereas 1-2 was better for rings.
 

sledge

Ideal_Rock
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With the tone in the reds here vs the older scope, is that attributable to anything in particular? The reds just seem hyper-saturated, and I don't know whether that's a reflection of the truly superior light performance, or whether the tone is shifted for further visual impact? Or... I guess, maybe it's as simple as the color used in the IdealScope has changed slightly over the years? I just want to try and be as close to apples-to-apples in my understanding as possible when looking at these images across different sites and figured no one would better be equipped to answer this than you :)

I was going to ask for links but noticed when I quoted you, the links became visible in my edit screen (but not in the standard “view mode”. This seems limited to BGD site links. I noticed it in other threads as well. I think it may have something to do with the forum software converting to an “advanced link” that gives a tiny glimpse of the linked page. Either that or the fact the BGD pages don’t end with a .htm or .html like the WF pages.

The other oddity I noticed is that it seems to be time sensitive. So when first posted the BGD links work but after a time period they go dead. Again, this happened in another thread where I got linked a BGD stone for possible purchase.

Dsomething happen in my absence that created BGD links to behave in this manner? Other links seem to work properly.

Reporting this post to mods so they can see & address.

Intentionally used the link button in the edit screen to create hot linked text identical to the web address trying to share.

2014 BGD link:
https://www.briangavindiamonds.com/1.224-h-vs1-round-diamond-ags-bl-104069928016

2019 BGD link:
https://www.briangavindiamonds.com/2.526-n-vvs1-round-diamond-ags-e-104098157001

2021 WF link:
https://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-3833677.htm
 

sledge

Ideal_Rock
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Images for clarity.

2014 BGD Blue:
799DE251-FBF8-447E-B7F8-332C9EBEA717.jpeg

2019 BGD Cape:
968825FC-0859-4B6C-BC75-E7946366B3F4.jpeg

2021 WF ACA:
5CB507D7-959F-4EC0-9D99-2C07B4F25BE7.jpeg
 

Avatar345

Shiny_Rock
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I was going to ask for links but noticed when I quoted you, the links became visible in my edit screen (but not in the standard “view mode”. This seems limited to BGD site links. I noticed it in other threads as well. I think it may have something to do with the forum software converting to an “advanced link” that gives a tiny glimpse of the linked page. Either that or the fact the BGD pages don’t end with a .htm or .html like the WF pages.

The other oddity I noticed is that it seems to be time sensitive. So when first posted the BGD links work but after a time period they go dead. Again, this happened in another thread where I got linked a BGD stone for possible purchase.

Dsomething happen in my absence that created BGD links to behave in this manner? Other links seem to work properly.

Reporting this post to mods so they can see & address.

Intentionally used the link button in the edit screen to create hot linked text identical to the web address trying to share.

2014 BGD link:
https://www.briangavindiamonds.com/1.224-h-vs1-round-diamond-ags-bl-104069928016

2019 BGD link:
https://www.briangavindiamonds.com/2.526-n-vvs1-round-diamond-ags-e-104098157001

2021 WF link:
https://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-3833677.htm

Thanks for discovering that! Yeah I had come back into the thread and noticed that the links had died... but could no longer edit the post. I was like: what in the world is going on?

That is really weird overall
 

Garry H (Cut Nut)

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The main variable there is the back lighting and focal plane.
This image is the chronological developments (L>R) of idea-scope and ASET (no blue in my earliest version from the late 1980's, which works better when used with backlight).
The soup bowls at the back are prototypes for DiBox that is used by most companies. I developed those about 10 or 12 years ago.
1619047421241.png
 

Avatar345

Shiny_Rock
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Messages
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The main variable there is the back lighting and focal plane.
This image is the chronological developments (L>R) of idea-scope and ASET (no blue in my earliest version from the late 1980's, which works better when used with backlight).
The soup bowls at the back are prototypes for DiBox that is used by most companies. I developed those about 10 or 12 years ago.
1619047421241.png

So that differential in the red tones/saturation levels is just down to backlighting and where in the cone the diamond lies then? Just seemed... dramatic!... and the sort of shift in coloration between the circa 2014 Brain Gavin diamond and the 2019 Brian Gavin made me wonder what the aspects at play were, since I would imagine amongst consistent super ideals it wouldn't be huge variations in the light return itself (though of course there are variations there as well).
 

sledge

Ideal_Rock
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Here's another one just to mess with you....hot pink, lol. If you aren't aware, this is a CBI/HPD idealscope from at least 1+ years ago.

idealscope_cbi.jpg

On a more serious note, vendors will have different scope, equipment & backlighting setups they use. And as time passes, those same vendors will upgrade to better equipment as the trend of buying online is growing stronger; therefore, the need for higher quality images are becoming more & more necessary. For instance, that last photo you referenced was a current day WF IS image. If you look back at some of the older ones, you can see how they too have evolved over time.

If you start looking at ASET's you will notice that BGD uses an orange based ASET with purples, etc. The standard is red, blue & green. And sometimes you will see different colored H&A images as well. My wife's stone is a BGD Blue stone and came with blue hearts as opposed to the more popular red.

In addition to slight color differences, some vendors will provide the images on a white or back background. Some vendors even provide both. I find black more pleasing to my eyeballs, but white is supposed to actually make it easier to detect irregularities. And I have confirmed that theory on a few items.

But rather than getting too hung up on the exact colors, you would be better served to learn how to read an IS, ASET and H&A image so that you can interpret what the image is trying to tell you. Here is a reference chart on IS images to help get you started.

Where it gets tricky is if a vendor uses too much backlighting, it can over saturate the true image and you have to do some additional detective work to determine if it's true leakage or just over saturation.

829005
 

Avatar345

Shiny_Rock
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Here's another one just to mess with you....hot pink, lol. If you aren't aware, this is a CBI/HPD idealscope from at least 1+ years ago.

idealscope_cbi.jpg

On a more serious note, vendors will have different scope, equipment & backlighting setups they use. And as time passes, those same vendors will upgrade to better equipment as the trend of buying online is growing stronger; therefore, the need for higher quality images are becoming more & more necessary. For instance, that last photo you referenced was a current day WF IS image. If you look back at some of the older ones, you can see how they too have evolved over time.

If you start looking at ASET's you will notice that BGD uses an orange based ASET with purples, etc. The standard is red, blue & green. And sometimes you will see different colored H&A images as well. My wife's stone is a BGD Blue stone and came with blue hearts as opposed to the more popular red.

In addition to slight color differences, some vendors will provide the images on a white or back background. Some vendors even provide both. I find black more pleasing to my eyeballs, but white is supposed to actually make it easier to detect irregularities. And I have confirmed that theory on a few items.

But rather than getting too hung up on the exact colors, you would be better served to learn how to read an IS, ASET and H&A image so that you can interpret what the image is trying to tell you. Here is a reference chart on IS images to help get you started.

Where it gets tricky is if a vendor uses too much backlighting, it can over saturate the true image and you have to do some additional detective work to determine if it's true leakage or just over saturation.

1619135736333.png

Thanks for posting that CBI IS image Sledge because that's almost the perfect distillation of what my question is on the matter!

Is that stone cut to *such* a high level that the white 'V's' [I don't know what to call them] typically found at the tip of the 'arrows' on the crown facets are now actually performing nominal light return? (And thus the pink'ish color) Or is the whole image so blown out with color saturation that fine detail in performance is being lost in translation?

If you look at the dead center of that CBI image, above the culet, you see that even darker pink/red tone normally associated with where the strongest levels of light return will be found in a diamond. If we look for *that* level of pink/tone throughout the rest of the CBI diamond, it maps to roughly where we see it in that original BGD scope image from 2014'ish. But for myself, that BGD image is so much easier to read/interpret for not being cranked up to day-glo levels lol.
 

sledge

Ideal_Rock
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Thanks for posting that CBI IS image Sledge because that's almost the perfect distillation of what my question is on the matter!

Is that stone cut to *such* a high level that the white 'V's' [I don't know what to call them] typically found at the tip of the 'arrows' on the crown facets are now actually performing nominal light return? (And thus the pink'ish color) Or is the whole image so blown out with color saturation that fine detail in performance is being lost in translation?

If you look at the dead center of that CBI image, above the culet, you see that even darker pink/red tone normally associated with where the strongest levels of light return will be found in a diamond. If we look for *that* level of pink/tone throughout the rest of the CBI diamond, it maps to roughly where we see it in that original BGD scope image from 2014'ish. But for myself, that BGD image is so much easier to read/interpret for not being cranked up to day-glo levels lol.

Those areas on the outside edge are supposed to be white. CBI's are awesome, but that is a saturation issue IMO.

Below is an IS image I have marked up that may help.

  • Green areas = normal to be white
  • Yellow areas = Center defines our control point for backlighting. Notice the pinkish color under the table (I circled just one, but multiple events occur) and how it is the same pinkish color as the center (or better)? All those areas are a result of over bright backlighting, and not true leakage.
  • Blue areas = these are noticeably whiter than our established control point and is indicating true leakage on the stone


Inked8EB601A3-CF9C-41F8-8067-ADC01E286299_LI.jpg
 

Avatar345

Shiny_Rock
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Those areas on the outside edge are supposed to be white. CBI's are awesome, but that is a saturation issue IMO.

Below is an IS image I have marked up that may help.

  • Green areas = normal to be white
  • Yellow areas = Center defines our control point for backlighting. Notice the pinkish color under the table (I circled just one, but multiple events occur) and how it is the same pinkish color as the center (or better)? All those areas are a result of over bright backlighting, and not true leakage.
  • Blue areas = these are noticeably whiter than our established control point and is indicating true leakage on the stone


Inked8EB601A3-CF9C-41F8-8067-ADC01E286299_LI.jpg

Well yes I'd say my skills at reading the IdealScope images are up to par at this point :)

I guess to be even less subtle about the question I'm asking though, I'm wondering if those hyper-saturated, pink vs red toned scope images, work to obscure areas of minor, minor leakage? White obviously won't be hidden, but in an image where even white can appear pink, it's that much harder to judge true performance under the table, know what I mean? In that original 2014 BGD scope the ring is solid but you can make out the variations in the ring in terms of light performance, in part because it's a straight-up photo of a normal IdealScope test case. In the CBI image, variations are almost impossible to discern because the hues chosen and the saturation create such a uniform image that... well, "that what" I don't know. But phrased differently - does the BGD diamond image represent peak perfection, and the images CBI is using over-saturated because it looks even more perfect, or is this in fact reflective of some greater point along the graph of asymptotic achievement?

Phrased in reverse: I wouldn't want purchasers of super ideal cut diamonds to become so used/accustomed to the imagery surrounding super-saturated scope results that the results of "normal" scoping imagery always seems to fall (way) short in comparison... but due solely for allowing for more contrast between the gradations.

It's like how big box retailers crank up the brightness and contrast on their screens when selling TV vs trying to reproduce color/lighting accurately as you actually would for your home theater, know what I mean?
 
Last edited:

sledge

Ideal_Rock
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I think what you are asking is the reason I prefer an ASET image. I prefer to see both images actually, but if I can only choose one then I believe ASET is a little more revealing.

Take for instance this WF stone currently for sale. It's an expert select and very well cut stone. I wouldn't have any problems buying or recommending the stone. It appears it missed ACA criteria because of slight imperfections in the hearts image at 2 and 8 o'clock. IMO, still a great stone that has been discounted & will make a future buyer very happy.


But more to our point, let's first take a peek at the IS image. As we can see, this is a very solid IS image and passes. However, if I am being extremely nitpicky I can see ever so slight hue variation under the table.

hearts-and-arrows-round-diamond-ags-104102925008-idealscope-183607.jpg

Now when I look at the ASET I get a similar, but slightly different representation. A couple of those areas I saw under the table now show up as green on the ASET. Technically all red is desired, because it shows optimal light return/brightness. Green is still good, but it is less optimal than red.

While technically less good, the green spots in question aren't going to affect the stone in a meaningful way that is appreciable to the naked eye. Yet, this is not as easily detectable on the IS image as it on the ASET image.

And if you are curious why the table reflection is a combo of red & green, you can read more in the article below. In short, the pavilion angles of 40.75 or less will reflect light at less than 45 degrees and be green. Pavilion angles of 40.77 or greater will reflect light above the 45 degree mark and be red.

hearts-and-arrows-round-diamond-ags-104102925008-aset-183604.jpg

 

Avatar345

Shiny_Rock
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Messages
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I think what you are asking is the reason I prefer an ASET image. I prefer to see both images actually, but if I can only choose one then I believe ASET is a little more revealing.

Take for instance this WF stone currently for sale. It's an expert select and very well cut stone. I wouldn't have any problems buying or recommending the stone. It appears it missed ACA criteria because of slight imperfections in the hearts image at 2 and 8 o'clock. IMO, still a great stone that has been discounted & will make a future buyer very happy.


But more to our point, let's first take a peek at the IS image. As we can see, this is a very solid IS image and passes. However, if I am being extremely nitpicky I can see ever so slight hue variation under the table.

hearts-and-arrows-round-diamond-ags-104102925008-idealscope-183607.jpg

Now when I look at the ASET I get a similar, but slightly different representation. A couple of those areas I saw under the table now show up as green on the ASET. Technically all red is desired, because it shows optimal light return/brightness. Green is still good, but it is less optimal than red.

While technically less good, the green spots in question aren't going to affect the stone in a meaningful way that is appreciable to the naked eye. Yet, this is not as easily detectable on the IS image as it on the ASET image.

And if you are curious why the table reflection is a combo of red & green, you can read more in the article below. In short, the pavilion angles of 40.75 or less will reflect light at less than 45 degrees and be green. Pavilion angles of 40.77 or greater will reflect light above the 45 degree mark and be red.

hearts-and-arrows-round-diamond-ags-104102925008-aset-183604.jpg


Very good point with respect to the ASET vs IS images... I've tended to prefer the IS images for quick reference on rounds just because they can paint a sort of binary picture right off the bat as to whether the stone is good or "not good." But the ASET point is well taken in terms of sifting through some of that ambiguity in terms of conveying specific performance. One of the things I have trouble with though on ASETs is determining clearly areas of light loss vs contrast (which is why I like the IS). Like in that image above, the black located at the base of the arrows underneath the table near the culet, I know, functionally, is likely contrast - but it appears here as light loss. It's that sort of judgment call stuff that makes it less quick/easy a point of reference for me to refer to.
 
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