Should I spend close to 12k on this diamond?

[teobdl]

Yssie--great counter scenario. But can JP comment on a competitor's specific item?

 

[Gypsy]

No he can't . The link would have to be removed.

 

[heididdl]

No ideal cut stone specs:

Table 54-58
Depth: 60-62.3
crown angle: 34-35

pavilian angle 40.6-41.0

this is a start I hope

 

[yssie]

No he can't . The link would have to be removed.

This is correct - it escaped my recollection.

I have requested that the moderators remove the link and I asked whether tradespeople can comment on that particular stone with just the still photo and the snippet of the report.
I am, however, admittedly more interested in learning more about the original stone!

 

[John P]

I was alerted to this and am replying remotely: it's a great example and question Yssie. I believe I can provide a reply that accommodates forum policies. Thank you for the consideration. I'll revisit this from my desk later.

 

[Dreamer_D]

Since the OP has seen the diamond in person then he/she is in a good position to judge subjective beauty! KC have you compared this diamond to other more "safely" proportioned diamonds -- like an AGS0 scoring under 2 on the HCA? And can you post the clarity plot? Where are the grade making inclusions located (the plot will tell you if there is a boogeyman under the prongs).

 

[yssie]

I was alerted to this and am replying remotely: it's a great example and question Yssie. I believe I can provide a reply that accommodates forum policies. Thank you for the consideration. I'll revisit this from my desk later.

Thank you!! Your time and thoughts are much appreciated, as always!

Since the OP has seen the diamond in person then he/she is in a good position to judge subjective beauty! KC have you compared this diamond to other more "safely" proportioned diamonds -- like an AGS0 scoring under 2 on the HCA? And can you post the clarity plot? Where are the grade making inclusions located (the plot will tell you if there is a boogeyman under the prongs).

That's the catch-22, isn't it!?
You can't truly trust your judgment until you've looked at enough stones to form an educated opinion on what your eyes are seeing.
But you can't trust anyone else to know what you will find 'most beautiful' either!
And you certainly can't expect new buyers to spend weeks - months - peering at "training diamonds"!!

I tend to err toward just trusting the AGS0 as well, unless the buyer is looking for something specific - but if a buyer is looking for a specific personality odds are good that he already has some understanding of what particulars to look for. I am very curious about John's determinations about the quality of cut and motivations behind cutting this particular stone, and others like the example I posted!

 

[yssie]

Since the link will be removed shortly:
https://www.agslab.com/reportTypes/pdqdf.php?StoneID=104067327043&Weight=1.013&D=1
AGS 104067327043
1.013

Okay, I'm lost!

John, I agree that the cutter must have been very adept! But how can we guess to what purpose was he showing off, if indeed he was? Was it merely to create an edge-case AGS0? (ie. what do you see here that I don't, and can I coax you into sharing it? )
And of course the bigger question is whether this type of edge-case AGS0 matches OP's definition of "beautiful".

Here's an edge-case AGS0 that I would definitely want more info on, for example:

 

[Ella]

No he can't . The link would have to be removed.

This is correct - it escaped my recollection.

I have requested that the moderators remove the link and I asked whether tradespeople can comment on that particular stone with just the still photo and the snippet of the report.
I am, however, admittedly more interested in learning more about the original stone!

Whether there is a link or not, a trade member cannot comment on a stone for sale. Please find one that is not for sale to discuss.

 

[John P]

I am very curious about John's determinations about the quality of cut and motivations behind cutting this particular stone, and others like the example I posted!

Sure thing. Let's keep it on neutral ground, to accommodate forum policies.

First, I should clarify what I mean by the edge of a "Cutting-Cliff."

Here are two excerpts from the AGS manufacturer's guides (reproduced with permission). AGSL provides them so producers can see the expected light-performance ballpark for various proportions-sets.

But these guides are general, not guaranteed. The result for an actual finished diamond also depends on minor-facet choices, the actual measurements being close to the given averages, the level of 3D cut precision/virtual facets and brillianteering choices. All of those things are accounted-for in the ray-trace and impact the final light performance grade.

Diamonds near 6mm with 57% tables.

I have circled Tolkowsky: 57 40.75 34.5


This excerpt is an area of well-known performance. Looking above, you can see how the numbers adjacent to the zeroes are largely 1s or 2s. It makes these sets smooth targets, in terms of acquiring minimum numbers for AGS0.

For long-time readers: Note that PA 41.0 needs care with CAs 34.3+. Such diamonds turn into zeroes with good consistency and proper minor faceting, but that ledge is why some purists won't go over 40.9 degrees with their dedicated-Tolk-makes... 41+ can become zero but they don't view it as the topmost-zero.

*

Now let's look at a Cutting-Cliff

Diamonds near 8mm with 57% tables.

I have circled the choice KC-BBQ's cutter made: 57 40.9 36.4


Now that's cutting on a cliff!

In the circled area zero is nearly an island (40.6 36.4) threatened by 3s and 4s. Directly above is a fall from 0 to 3, primarily related to brightness. Beyond that comes a fall to 6 that's about physical leakage. Brightness can be improved with tradecraft, but when you get to leakage it's largely unavoidable.

So why did he/she choose this target? Why the island-area? If weight was no consideration it's safer to reduce PA to 40.6 or both PA and CA to 40.7/35ish. Either would be a safer ideal, while still qualifying for GIA EX. I'd wager no 2ct ideal was possible, so they went for keeping 1.9X by using this combo and employing smart brillianteering choices that popped the AGS0.

That's what I mean by a Cutting-Cliff.

The risks above contribute to the reasons AGSL receives a fraction of diamonds compared to other labs. Even if a producer shoots for AGS0 he can't know for sure until AGSL tests how all 57 facets work together using 3D ray-tracing. AGS does have software available so a scan can be run to see what performance grade is predicted, but few producers bother. Since other lab systems use average proportions, producers only need to target the 2D proportions they know will get X, Y or Z cut grade. Far easier.

In response to requests for a chart-based system AGS introduced the more lenient "Gold" metric. This mimics the GIA approach (and the pre-2005 AGSL approach) using averaged 2D proportions for a predictive grade that's not diamond-specific. The Gold system also permits polish and symmetry to be less than 'Ideal' and still earn the overall Gold Ideal grade. Once in a while we see someone linking-to the Gold lookup charts on Pricescope, thinking they relate to the Platinum metric. They do not.

Returning to the cliff... Here is an example of a cutter "going-for" the kind of proportions KC-BBQ's diamond has. I presume the Gold report was requested because some aspect slipped off the cliff and it didn't make Platinum Ideal.

http://www.agslab.com/pdf_sync_reports/104058169001-GDQR.PDF
(this is not a diamond for-sale on PS).

A wise producer might also submit it to another lab, for paper that moves well outside the USA. 4.53 is a nice size on any continent!

 

[John P]

John, I agree that the cutter must have been very adept! But how can we guess to what purpose was he showing off, if indeed he was? Was it merely to create an edge-case AGS0? (ie. what do you see here that I don't, and can I coax you into sharing it? )

Yssie, I hope the above explained the "showoff" aspect I was talking about. While not all borderline choices are on a cutting-cliff, this one was.

And of course the bigger question is whether this type of edge-case AGS0 matches OP's definition of "beautiful".

Absolutely. I presume that's the biggest question for anyone. It absolutely relates to different makes, including those on cutting cliffs, and respective visual flavors. I hope to post more later.

 

[Just_Starting]

Really enjoyed reading your posts John, very informative. Thanks for sharing .

 

[Bonfire]

Thanks John for taking the time to illustrate and explain so well. I think we all learned from that
More, tell us more!!