Critical Analysis - Interesting Stone

[Jnana]

Good afternoon PS,

What would you think of a stone like this:

Measurements
5.85 - 5.87 x 3.60 mm
G VS2, Triple Excellent, H&A
0.75 ct
Fluorescence None

Table
55.9%
Crown Angle
34.6
Crown Height
15.2%
Girdle
Faceted, 1.4% to 3.4%
Girdle Description
Thin to Medium, Faceted
Pavilion Angle
40.8
Pavilion Depth
43.1%
Star Length
53%
Lower Girdle Length
77%
Total Depth
61.4%


Obviously, this is an above average stone. I would prefer to see the 5.85-5.87 size be more symmetrical, 5.86-5.86.
The crown angle is a little open, a tighter 34.5 would be an improvement to this stone
I would take the Lower Girdle down to 75 or 76, fatten up the arrows
To me 61.4% depth is too deep, shave off 0.2%

What are your opinions? Thank you so much.

 

[sledge]

I think I'm picky and you are being more picky than me.

That stone will be freakin' gorgeous. The stone being 5.85 x 5.87 is great. Very, very few stones are exactly perfect @ 5.86 in this case.

But since we are picking....

• 54-55 table
• 34.5 crown
• 75 LGF
• You had a typo in your analysis of the depth....not 64.4 but rather 61.4.

I'm not sure we could see the difference in a 34.5 and 34.6 crown with all other elements being identical. You might see a little on the table, but it'd be very minimal.

If you were looking at GIA stones, the 77 LGF would be graded as a 75 LGF.

Seriously, the arrows will still be fairly fat @ 77. Not sure how much light performance you'll actually see. 75 tends to do better in dark environments, whereas 80 does better in brighter environments. IMO, 77 is kind of splitting the difference. Consider the size of the stone too. Will you see any size difference in the arrows in a non-magnified view with it only being a 0.75ct?

 

[crbl999]

Great choice. Super ideal specs. Have you seen an image of the hearts? Should be good to go, but I always like to view them since it is being sold as H&A.

 

[OoohShiny]

You can tell the difference between 5.86x5.86mm and 5.85x5.87mm by the naked eye alone?

Is your name Clarke Kent?

 

[MissGotRocks]

Your critic is too critical in my opinion. I understand your ideal numbers but seeing the difference in person would take super human eyes!

 

[Jnana]

 

[Johnbt]

Eyeball this WF ACA...

How round is this 1.5 carat? I'll look up the L & W and post them in a minute if I can find the link. The ring just walked in the door.

 

[Johnbt]

Had to reboot the router. Grrr.

Here's the link www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-3955177.htm

Measurements 7.35 x 7.44 x 4.55 mm

Hundreds of people have seen it up close in its 6-prong Vatche setting and not one has said, "Hey, that's not round."

.09 mm = 0.003543307 inches

Assuming half of that 3-thou-and-change is on one side and half is on the other, the opposite fat sides are each only off .00177165 inches.

 

[Jnana]

Hundreds of people have seen it up close in its 6-prong Vatche setting and not one has said, "Hey, that's not round."[/QUOTE]

Fair enough, but wouldn't this exact stone reflect light better without the oblongness.

 

[crbl999]

Hearts look great! You've got an amazing diamond picked out.

 

[Johnbt]

April 10th, the day we received it. We took a break from yard work. Late afternoon sun is coming through double pane windows and wooden blinds from behind her right arm. Her left hand is on the chair arm.

There were colorful dots on her shirt, her face and her jeans. Who could ask for anything more?
And I hadn’t even cleaned the lens on my old iPhone.

 

[Johnbt]

...and I thought for a time that just maybe all of those wonderful, colorful Whiteflash videos were a product of some flashy camera work and expensive lights. Then we got the ring. Nope, no tricks. The diamonds are doing all of the hard work.

 

[Lookinagain]

Fair enough, but wouldn't this exact stone reflect light better without the oblongness.

the diamond in that photo looks oblong to you? And 5.85-5.87 indicates it is oblong? Wow. I'm not sure the kind of symmetry you are looking for exists. Or is required to make something beautiful. But that's just my personal opinion of course.

 

[sledge]

Hey @Johnbt, am I correctly seeing this stone is oblong along the vertical axis I've drawn in red below?

Just curious, but did this meet WF's ACA requirements? I don't think I've seen so much variance in the L & W dimensions. Interesting.

 

[OoohShiny]

This feels like one of those optical illusion circular emails / facebook posts... lol

 

[Johnbt]

"Hey @Johnbt, am I correctly seeing this stone is oblong along the vertical axis I've drawn in red below?"

Honestly? It beats me. We liked the stone so much on line we ordered it. We watched videos and picked the one that had the color flashes we liked best. I was half expecting to be able to tell it was out of round, but for the life of me it looks round. And I would have noticed, I'm really picky when it comes to bad proportions in real life, trust me.

I think the thing to do is to rotate the pic. Every single time I thought I had figured it out I'd rotate the pic (or turn the laptop or phone sideways) have to start over.

I even put it under an old microscope my uncle gave me in the early '60s. That was no help. Then I thought about breaking out my Starrett calipers... nah. Enough was enough. She's happy, I'm happy. The ring is perfect. Women have asked her if I'm adopting.

Anyway, everything I've ever read said that that a difference of 0.1 mm is acceptable and can't be seen.

She wanted a diamond that was alive and colorful. WF came through big time. Everything else is just a bunch of numbers.

Time for my second cup of coffee. Retirement is wonderful.

 

[Johnbt]

...and to measure the dimensions on photo we'd have to know the diamond wasn't ever so slightly tilted when they shot the pic.

 

[tyty333]

Eyeball this WF ACA...

How round is this 1.5 carat? I'll look up the L & W and post them in a minute if I can find the link. The ring just walked in the door.

Oh my word...are you going to set it N/S or E/W? Its so out of round!

In case my sarcasm didnt come across, I am just kidding. Lovely stone!

 

[tyty333]

Good afternoon PS,

What would you think of a stone like this:

Measurements
5.85 - 5.87 x 3.60 mm
G VS2, Triple Excellent, H&A
0.75 ct
Fluorescence None

Table
55.9%
Crown Angle
34.6
Crown Height
15.2%
Girdle
Faceted, 1.4% to 3.4%
Girdle Description
Thin to Medium, Faceted
Pavilion Angle
40.8
Pavilion Depth
43.1%
Star Length
53%
Lower Girdle Length
77%
Total Depth
61.4%


Obviously, this is an above average stone. I would prefer to see the 5.85-5.87 size be more symmetrical, 5.86-5.86.
The crown angle is a little open, a tighter 34.5 would be an improvement to this stone
I would take the Lower Girdle down to 75 or 76, fatten up the arrows
To me 61.4% depth is too deep, shave off 0.2%

What are your opinions? Thank you so much.

I would pass on this stone for all the reason you mentioned...

And what do you find so interesting about this stone (according to your title)?

 

[sledge]

I think some people may be able to see 0.10mm difference but I definitley don't think that's the norm. Its 1/256th of an inch!

Most normal people start to detect differences around 0.20mm as pointed out.

I would agree that if someone out of the clear blue asked about it being out of round I'd probably smack'm silly.

Enjoy the coffee and retirement!

 

[Johnbt]

Thank you.
_____________

"Oh my word...are you going to set it N/S or E/W? "
I don't know what they did. Four compass points and a Vatche U-113 has 6 prongs.

______________

People always talk about eye clean.
Maybe we need to add a term - eye round.

Does anyone believe that a stated diameter measurement of, say, 6.74 mm is always precisely 6.74 mm? Or is it rounded up from, oh, 6.7352 mm or down from 6.7439 mm? So a 6.74 x 6.74 isn't necessarily perfectly round.

Eye round. If it looks like a circle, it is a circle.

 

[Jnana]

I sort of understand that these small differences are hard to detect. I don't think I could tell a 34 from 39 crown angle by eying the stone's angles. I think it would be reflected (lol) in the light performance.

What about this even more believable scenario. A genie with perfect measuring equipment offers to make a stone you are considering even more round by .01 mm and all other proportions are maintained beautifully (You ain't never had a friend like this). Would you make this wish?

 

[ringo865]

I would not use my wish for that. No.

 

[OoohShiny]

What would be the point if it makes no visual difference?

 

[OoohShiny]

If you are obsessed with all the numbers being identical, don't ever get one of the scans that are available, such as that which @lovedogs had done...

https://www.pricescope.com/communit...m-slight-brown-1ct-stone.243106/#post-4399486

Cutting diamond is not like cutting cheese - one has to work with the material's internal structure and grain, like working with wood or stone, so it is a near-impossibility to get an exactly matching set of numbers per facet group.

I'm sure even CBI's cutting standards can't reach that level of perfection - @John Pollard could confirm.

 

[sledge]

People always talk about eye clean.
Maybe we need to add a term - eye round.

Does anyone believe that a stated diameter measurement of, say, 6.74 mm is always precisely 6.74 mm? Or is it rounded up from, oh, 6.7352 mm or down from 6.7439 mm? So a 6.74 x 6.74 isn't necessarily perfectly round.

Eye round. If it looks like a circle, it is a circle.

LOL, we sort of do already. If it's too out of whack, we call it an "oval".

Seriously though. I think there is a difference in being technically right, and reasonably right. To me, if I have to carry out to 4 decimals to find variance in a 6.74mm stone then that's close enough.

I'm not picking on your stone by any stretch, but 0.10mm would probably bother me a bit. It makes me think of the other properties and most slight symmetry issues that may exist. If you have the detailed report from WF like @lovedogs got with her stone then I think you'd see other variables of higher variance too. Just my suspicion.

The real question becomes does the minor variance have a meaningful impact? Judging by your happiness and the sparkles I saw on your wife's shirt, I'd say it didn't hurt performance in any meaningful way.

I sort of understand that these small differences are hard to detect. I don't think I could tell a 34 from 39 crown angle by eying the stone's angles. I think it would be reflected (lol) in the light performance.

What about this even more believable scenario. A genie with perfect measuring equipment offers to make a stone you are considering even more round by .01 mm and all other proportions are maintained beautifully (You ain't never had a friend like this). Would you make this wish?

My guess is if you are cutting diamonds then you may start to have an eye that could see 5 degrees of variance, especially on larger stones.

But for the normal Joe, probably not.

That said, unless you are near blind you better damn well see a light performance difference in a stone with a 34 crown and 39 crown. If not, you are either very untrained on what a good diamond looks like, or you should go visit an optometrist.

But I seriously doubt a human could detect any difference between a stone with 34.5 or 34.6 crown angle, which is what spawned this conversation. Would I prefer a 34.5 angle? Sure. Would I ever reject it for 34.6? Never.

If you are obsessed with all the numbers being identical, don't ever get one of the scans that are available, such as that which @lovedogs had done...

https://www.pricescope.com/communit...m-slight-brown-1ct-stone.243106/#post-4399486

Cutting diamond is not like cutting cheese - one has to work with the material's internal structure and grain, like working with wood or stone, so it is a near-impossibility to get an exactly matching set of numbers per facet group.

I'm sure even CBI's cutting standards can't reach that level of perfection - @John Pollard could confirm.

Ahhh, yes.....the bastard 69.9 degree LGF amongst all the other 80 +/- LGF's.

 

[Jnana]

I am very interested in what people would wish for. I mean what are we searching for in all of these stones if not the best one. No matter the standards that these cutters are striving for, they should eventually turn out a few that have beyond super ideal specs with ultra tight variances. Like 8 measurements of 34.500, just on accident. Let me know if you see one for sale. =P

Here is some more info, not what Mr. Dogs has obtained but I would love nothing more that info like that on all ideal stones in the market.



I believe any change in proportion will lead to a change in light performance. Is there a tendency to shy away from a more detailed examination of cut like this because many of the stones fall short in the market place?

I value the feedback and discussion.

 

[OoohShiny]

Crafted by Infinity are probably the tightest cutters of MRBs - they only cut around 1000 a year and spend more time than others (AIUI) on ensuring facet accuracy and alignment in order to deliver improved light performance.

There are ongoing discussions around whether this creates a visible difference compared to other, 'normal' SuperIdeal stones. Some have said Yes after viewing them side-by-side, others have said No.

CBI would certainly argue that improved consistency of facet groups yields better light performance, I'm sure (@John Pollard would be able to confirm) but how much does one facet being 0.1degree off from the rest actually affect light return/performance?

Unless you are on the absolute border of the refractive/reflective angles within diamond, I doubt anyone in real life would actually be able to tell the difference.

And even if they could, you are so far past the 80/20 rule that you aren't even in the 'shades of grey' area anymore - you've moved into the 'shades of Brilliant White' section of the paint chart

To most cutters (and the wider market), GIA XXX 'will do'.
To some cutters, GIA XXX with a tight range of angles/measurements within facet groups will do.
To a few cutters, AGS 000 is what is needed.
To very few cutters, AGS 000 within narrower ranges of crown/pavilion angle combinations is the minimum requirement (the 'SuperIdeals').


Even within the PriceScope forum, there are people who are happy with the various options - and often the trade-off has to be made somewhere in order to balance the 4Cs out to a satisfactory result.

For example, would you want a 0.25ct 'UltraSuperIdeal!!!' with all facet groups within 0.001 tolerance?

Or, for the same cost (because cutting time costs money) a decent but 'sloppier' GIA XXX of 0.5ct that fitted within the PS-/HCA-recommended angles and looked (compared to 99% of the stones on the market) better than anything 99.99% of the public has seen in the shops, but which had a range of angles/measurements under a Sarin scanner?


The fact is that 'perfect cuts' (however you define that in terms of accuracy / tolerances / grading report standards) are rare and expensive, due to the time and taken to get them to that level, and the fact that the market for them is small due to the associated additional cost for (arguably) benefits that can be hard to define. Whether this might change with increasing use of Man Made Diamonds / Lab-Created Diamonds (which may or may not be easier to cut due to more consistent internal structures), I don't know, but I wouldn't be betting money either way for the foreseeable future.

 

[yssie]

My opinion: this sort of quibbling is a largely wasted effort.

Measurements are only as accurate as the devices used to take them, regardless of precision. Here's the listed accuracy of one commonly-used non-contact scanner - and this is assuming the device is perfectly calibrated:
https://sarine.com/products/diascan-s-2/
So that stone that's 5.85x5.87mm might actually be 5.86x5.86mm. And the stone that's presented as 34.0[...] all the way round may well not be.


I believe any change in proportion will lead to a change in light performance. Is there a tendency to shy away from a more detailed examination of cut like this because many of the stones fall short in the market place?

The assertion that minute asymmetries will present as side-effects in light return is not technically incorrect by any means. It is, however, an entirely impractical observation: the human eye has limits and side-effects of a stone being 0.02mm out-of-round, to reuse that example, would be well beyond visual critique. And diamonds - as used in jewellery - exist solely for visual critique. @OoohShiny outlined some reasons some vendors will shy from detailed analyses like this. Some vendors do provide scans and additional info, as they cater to a niche market of consumers who appreciate (and will pay extra for) that information.

 

[sledge]

I am very interested in what people would wish for. I mean what are we searching for in all of these stones if not the best one. No matter the standards that these cutters are striving for, they should eventually turn out a few that have beyond super ideal specs with ultra tight variances. Like 8 measurements of 34.500, just on accident. Let me know if you see one for sale. =P

Here is some more info, not what Mr. Dogs has obtained but I would love nothing more that info like that on all ideal stones in the market.



I believe any change in proportion will lead to a change in light performance. Is there a tendency to shy away from a more detailed examination of cut like this because many of the stones fall short in the market place?

I value the feedback and discussion.

Judging by the hearts image you posted I am assuming this is probably a WF stone. Are you aware that for picky buyers WF makes available the ADVANCED Sarin report?

https://www.whiteflash.com/about-diamonds/diamond-education/sarin-diamond-reports-1512.htm

I'm not feeling well today and fell asleep while @yssie and @OoohShiny hit on a few points I had in mind. I will leave the conversation there. Maybe you will get lucky and find your "perfect" stone.