Safe to proceed without ideal scope?

[Glory2014]

We are in the process of purchasing a diamond from James Allen, which they will also set. I had their gemologist inspect and compare three stones for me but at the time I did know I could request IS images. I have learned more doing reading on this and other sites.

The stats are:
GIA xxx
Table - 59
Depth - 59.6
Crown - 34
Pavilion - 40.6
HCA - .9 (ex across board)

The gemologist said the diamond has strong and lively light performance with excellent brilliance, fire and scintillation. Inclusions not seen by naked eye.

Given the above do you think this is a safe bet even though I don't have the IS image. How likely is it that a stone that does well on the HCA would have a poor IS result? Also can I have the IS performed after it is set?

Thanks in advance for your help!

 

[diamondseeker2006]

The time to request the idealscope image is now, before you buy and before the diamond is set. The HCA is an initial screener, and then you narrow down the stones further with the idealscope image. I would not buy without it. This is a vendor that offers it, so it would be a mistake not to get the image before making a decision.

 

[Lorelei]

We are in the process of purchasing a diamond from James Allen, which they will also set. I had their gemologist inspect and compare three stones for me but at the time I did know I could request IS images. I have learned more doing reading on this and other sites.

The stats are:
GIA xxx
Table - 59
Depth - 59.6
Crown - 34
Pavilion - 40.6
HCA - .9 (ex across board)

The gemologist said the diamond has strong and lively light performance with excellent brilliance, fire and scintillation. Inclusions not seen by naked eye.

Given the above do you think this is a safe bet even though I don't have the IS image. How likely is it that a stone that does well on the HCA would have a poor IS result? Also can I have the IS performed after it is set?

Thanks in advance for your help!

Hi Glory and welcome!

I agree with my esteemed friend The Seeker, this diamond is one I would definitely want an Idealscope image for due to the proportions. Depending on the overall cut precision and as GIA's proportions are rounded, there is a chance the diamond could show an effect called obstruction. This is an effect that shallower proportioned diamonds can show when worn in a ring viewed at close scrutiny. This stone might be absolutely fine or it could look dark at some angles in a ring, so an Idealscope image would be very useful in order to evaluate this diamond properly. As DS mentions, the diamond is from a vendor that offers IS images, so definitely request one to be on the safe side.

 

[diamondseeker2006]

It might also help us for you to also post a link to the stone. Sometimes obstruction can be seen on the video.

 

[JulieN]

Post the links.

 

[pyramid]

Notice the Table is 59%. Most on here try to keep the Table below 57%. A 34 degree crown angle usually has a deeper pavillion up to 40.9 degrees, or a shallower pavillion of 40.6 degrees is usually paired with a crown angle a bit deeper of about 34.6 - 34.9 degrees. Most are looking for depths over 60% but below 62%. There are other proportions which work as yours does with the HCA but with the GIA rounding in their cut grade method you would need to further investigate this one.

 

[Glory2014]

They will be providing the ideal scope image. Will post it once I have it.

 

[Glory2014]

I'm not sure if this is going to attach, but here is the ideal scope image. Please tell me what you think.

 

[TC1987]

Looks fine to me. Personally, I'd be willing to trade a little (possible) obstruction (only a problem at close range; also look up "head shadow" or "pendant stone" here) for that bit of extra spread that scored EX instead of VG on the HCA. Most of the time, the wearer isn't sitting around staring at the diamond close-up. Bystanders almost always are going to see it at arm's length. Size matters, lol.

The diamond that you picked looks like a very nice 60/60 to me. 60% table, 60% depth. Lots of PS people would want a smaller table say 54-56% and steeper crown angle and perhaps 15% crown height, for lots of fire. Just look at the diamond when you get it, and if there isn't enough fire or it's all out around the rim due to the larger table, and/or you just don't like the look of it, send it back. I have an old diamond that's probably 65% table and I know it's only 58% depth. It's in a ring, and everyone thinks it looks great in a ring, even though those proportions are what most of PS would maybe use in a pendant but not a ring. Larger table just gives a different look than a small one, is all.

 

[Glory2014]

Thank you. Yes, I liked the added spread, especially since I wanted something close to a carat without going over because of the price point. I did additional research on cut proportions, and when I saw this one it seemed to have nice proportions and looked really nice on the website.

It is a .91, H, SI2, 6.30 x 6.33 x 3.76. So it is bigger than most of the diamonds I have seen in that carat weight, but still has the excellent cut. Cost is right around $4,500. To help narrow down, I set my search for .90 H color, SI 2, and only excellent cuts because those were my lowest limits, then I looked at the more expensive diamonds listed with the same specs because I figured they were priced higher for a reason. I feel really good about finding this one and I can't wait to see it! The people at James Allen have been a pleasure to work with.

 

[teobdl]

Looks overall good. Some significant brillianteering on parts of the girdle which may further reduce fire. (1 and 3 o'clock) but the crown facets are very open which can be nice in letting out some more of the contrast.

Did the gemologist review any other diamonds alongside it?

I don't completely agree with the methodology of searching for higher price within a certain spec at JA--because the inventory is so big, the pricing is related to many other factors in addition to cut and quality. Looks like you're ending up with a fine diamond though!

 

[Lorelei]

I'm not sure if this is going to attach, but here is the ideal scope image. Please tell me what you think.

It's an excellent image and it should be a beautiful diamond with potentially a good mix of performance as the gemologist notes, I think it's definitely worth shortlisting for potential purchase.

 

[John P]

Looks overall good. Some significant brillianteering on parts of the girdle which may further reduce fire. (1 and 3 o'clock)

Hi Teobdl,

May I ask; how are you arriving at this conclusion?

Thanks,

JP

 

[proto]

I think he means painting the crown, as there is some red on the idealscope where you normally see tiny gaps.

My understanding was that painting helps get the edges of the IS totally red.

i did not think that painting affected brilliance/sparkle in a negative way though

 

[teobdl]

John--based on your comment, I assume my logic is incorrect. Please correct.

My thought process:
To my eyes, the girdle at 1 and 3 shows deep painting similar to the bottom IS's of Photo Compilation 5 here: https://www.pricescope.com/journal/visible_effects_painting_digging_superideal_diamonds

I assume the painting in the OP's IS is deep because of the very significant loss of patterning in those two spots. More shallow ACP (which doesn't affect performance) maintains the patterning more clearly, whereas deeper ACP shows more significant loss of patterning at those spots.

My specific questions for you are
1) Can we judge from an IS how deep the painting is? My assumption was "yes".
2) If yes, how deep is the painting in this specific IS? My read was closer to the deeper end of ACP where it may affect performance.
3) If the painting is closer to the deeper end as shown in Photo Compilation 5 linked above, how much might 2 places on the girdle affect performance? My interpretation was that it might affect performance negatively.

Please correct my reasoning. Always eager to learn.

 

[Karl_K]

ok, 40.6 pavilion is fine if the angles are close to 40.6 which is an unknown with the gia averaging and rounding.
The only way to tell is to look at it up close.
A lot of the time it is fine with no obstruction issues.
As long as the pavilion does not drop below the point of obstruction this in my opinion is one of the top 60/60 style diamond proportion sets.

 

[Karl_K]

John--based on your comment, I assume my logic is incorrect. Please correct.

My thought process:
To my eyes, the girdle at 1 and 3 shows deep painting similar to the bottom IS's of Photo Compilation 5 here: https://www.pricescope.com/journal/visible_effects_painting_digging_superideal_diamonds

I assume the painting in the OP's IS is deep because of the very significant loss of patterning in those two spots. More shallow ACP (which doesn't affect performance) maintains the patterning more clearly, whereas deeper ACP shows more significant loss of patterning at those spots.

My specific questions for you are
1) Can we judge from an IS how deep the painting is? My assumption was "yes".
2) If yes, how deep is the painting in this specific IS? My read was closer to the deeper end of ACP where it may affect performance.
3) If the painting is closer to the deeper end as shown in Photo Compilation 5 linked above, how much might 2 places on the girdle affect performance? My interpretation was that it might affect performance negatively.

Please correct my reasoning. Always eager to learn.

Yes you can tell if the picture is perfect or there is a lot, this one isn't perfect its slightly tilted.
Different proportion sets have different size leakage areas, in this set they are tiny.
That's normal.
So combine a small leakage area and slight tilt and it can look painted even if it isn't beyond the point all diamond are.
All diamonds have some degree of digging or painting even from the best cutters in the world.
The cutting tolerances are such that its impossible to have exactly none. Well unless by accident.

 

[John P]

John--based on your comment, I assume my logic is incorrect. Please correct.

Teobdl, I asked because you're a gifted technical poster - always engaging in productive dialogue - and wondered if you were operating on something I wasn't seeing.

You referenced an article I composed on painting/digging which explains your conclusions. You may enjoy knowing more to the story, having to do with environment, setup, orientation and gemological features. Karl hit the basics and I agree with his assertions for this stone. For the OP I just think I'd clarify that I see no reduction in fire or brightness here.

I'm on a plane and they're closing the doors now. But I'll try to return via wifi at 35,000 feet to elaborate.

Such cool times we live in.

 

[John P]

To the original poster: Please forgive a technical cut-assessment sidebar.

Reference: https://www.pricescope.com/journal/visible_effects_painting_digging_superideal_diamonds
When I composed that article I noted a correlation to the 0-25 angular draw in ASET and graduated appearances in ideal-scope. As I'm sure you know, painting of the crown brings the upper-half angles closer to each other. Painting of the lower halves does the same albeit the implications are more extreme (see comparison chart 1).

The junction where crown and pavilion mains meet at the girdle creates natural kite-shaped areas seen as leakage in IS and backlit ASET, or as drawing lower angled LR in a non-backlit ASET. The junction where upper and lower halves meet (at the split) creates similar areas which have the same leakage/less-bright footprint, but those 'claw-shapes' are longer and more narrow which makes sense, given the associated angles.

Here is a wire-frame juxtaposed with a modern Tolk non-backlit ASET.


With normal indexing, and depending on the structured light environment, the areas in question can be green or white in ASET. In Ideal-Scope, which is always backlit and makes no distinction between 0-25 and 25-75 (as ASET does) they can be white, pink or red, depending on how they combine with each other, crown to pavilion.

In Photo Compilation 5 from the referenced article I enjoyed an advantage: The photo setup was exactly the same, the diamonds were checked and double-checked for parallel alignment with lens to table (a fancy way of saying no tilt) and they were known actors which had crown-only painting. There were no other variations. All had normal pavilion indexing. It was an extremely controlled experiment and your conclusions are logical.

Not all situations are equal. That's fine. Frankly, those sellers who provide Ideal-Scopes and/or ASET are already going far beyond what is "conventional," so it's a plus and I hope we won't penalize them for doing-so. Karl has noted some of the reasons you can see footprints in Ideal-Scope which may appear as indexing variations (in a strictly controlled situation) and yet may not be. To elaborate...

Tilt is the most conspicuous creator of aberrations, as it shifts the fundamental angular spectrum. Karl covered this. Environment is also key. If the Ideal-Scope has a smudge on the outside, the plastic is thicker in one compass-point, the lighting is not uniform or the photographer accidentally blocks some light with a finger it can cause a similar "read" where those claws appear to draw light from lower angles. Gemological properties can also influence these photos. Clouds (especially), as well as feathers and crystals which have negligible impact on naked-eye performance can make themselves known in zoomed photos and can change the coloration in IS.

ASET is more friendly to the kind of analysis you're working to make. With that said:

My specific questions for you are
1) Can we judge from an IS how deep the painting is? My assumption was "yes".
2) If yes, how deep is the painting in this specific IS? My read was closer to the deeper end of ACP where it may affect performance.
3) If the painting is closer to the deeper end as shown in Photo Compilation 5 linked above, how much might 2 places on the girdle affect performance? My interpretation was that it might affect performance negatively.

1. In a standardized/known environment with no tilt and no gemological issues, yes. But we have to make room for other situations, and I prefer not to penalize the folks who work to provide these images.
2. I'd need an ASET image to postulate an answer. Or (gasp) a 3D scan I could put in DiamCalc
3. That is a key question...

While it's true that painting the upper halves can cause the 'claws' in Ideal-Scope to redden - utlimately to the point of consistent red and no leakage areas - this is a type of brillianteering variation which can actually be appealing (I know you know the old discussions of 8* etc). Digging is far more deleterious, and would result in unavoidable leakage (white) in IS. In certain types of diamond I think crown painting, in moderation, can be extremely beautiful. That's a taste thing. Others may disagree. That's fine - and really doesn't matter in this thread, since I don't think it's topical here.

Bottom line: Tempest in a teapot maybe? It's a darn nice Ideal-Scope image

Always eager to learn.

And you're always eager to share knowledge. It's why so many people value your contributions here.

I appreciate the opportunity to elaborate.

 

[teobdl]

A little knowledge can be a dangerous thing . Thank you, John, for the thorough, but gentle, correction.

 

[Lorelei]

A little knowledge can be a dangerous thing . Thank you, John, for the thorough, but gentle, correction.

That's true Teo but it's also good to ask about these things, painting and digging has been a very interesting topic of conversation over the years and I am sure it will continue to be in future for those of us that enjoy those details or want to learn more, but not all do I find!

Sir John has a knack for guiding us in the most elegant way, one of the many reasons why we appreciate him!

 

[Glory2014]

Wow!! Glad my post sparked such an interesting discussion. I definitely don't mind the technical info because it was my quest for additional knowledge and information that led me to this forum in the first place.

Digging and painting? I had not even gotten that far and probably can't take one more thing to obsess over, but you all are really on top of your game!

Decided to proceed with this stone and I appreciate the confidence you all have given me with your knowledge and info. I will likely keep reading and learning. Thank you!!!

 

[Lorelei]

Wow!! Glad my post sparked such an interesting discussion. I definitely don't mind the technical info because it was my quest for additional knowledge and information that led me to this forum in the first place.

Digging and painting? I had not even gotten that far and probably can't take one more thing to obsess over, but you all are really on top of your game!

Decided to proceed with this stone and I appreciate the confidence you all have given me with your knowledge and info. I will likely keep reading and learning. Thank you!!!

LOL! You could certainly obsess over painting and digging if you so desire, some really enjoy the really geeky stuff! Here is a taster thread for you just in case you fancy a spot of decorating and gardening....

https://www.pricescope.com/journal/visible_effects_painting_digging_superideal_diamonds


Thanks for your kind words too, there is a lot to learn and to keep up with in the diamond world even as consumer hobbyists but thanks to our friendly experts such as Sir John sharing their knowledge and latest info with us, we are able to help others!