Need help! GIA xxx diamond but terrible holloway - why?

[lucida]

Hello,

I always look to Pricescope for assistance. So I'm looking to buy a GIA certified diamond. The image is attached.
2.01 carat
xxx
G color
vs2 clarity

I plugged in the data in Holloway and it gave back a 6!!!! I've never seen such a poor score.
So they are a pair of studs with identical (almost) GIA reports. The other diamond scored a 1.9 on the Holloway and this one was a 6. Anyone out there can please explain this to me? I tried it both with the angle and % options (one came back at 6 and the other at 5.9). I wasn't even going to plug it in thinking that it was XXX and there would be no need to even plug it in, but I figured I'd try it. So for it to shine briliantly, I thought it had to have per fect cut (XXX). But this doesn't make sense to me.

Any ideas or suggestions?
I've attached the GIA for your review.
Thank you in advance!

 

[bunnycat]

Hello,

I always look to Pricescope for assistance. So I'm looking to buy a GIA certified diamond. The image is attached.
2.01 carat
xxx
G color
vs2 clarity

I plugged in the data in Holloway and it gave back a 6!!!! I've never seen such a poor score.
So they are a pair of studs with identical (almost) GIA reports. The other diamond scored a 1.9 on the Holloway and this one was a 6. Anyone out there can please explain this to me? I tried it both with the angle and % options (one came back at 6 and the other at 5.9). I wasn't even going to plug it in thinking that it was XXX and there would be no need to even plug it in, but I figured I'd try it. So for it to shine briliantly, I thought it had to have per fect cut (XXX). But this doesn't make sense to me.

Any ideas or suggestions?
I've attached the GIA for your review.
Thank you in advance!

GIA XXX is a broad category. Not all diamonds that fall in to GIA XXX also fall in to Ideal cut territory.

In this one, the pavilion angle look like 41.8, which is over the recommended pav angle for an ideal cut stone of max 41.

 

[flyingpig]

look at the chart again. See where "X" is situated. It is barely GIA ex.
As the previous poster said, GIA ex cut grade is very board. Just see the difference between the dotted border (GIA ex), and the solid line border (AGS 0).

While I respect GIA's color and clarity grading, GIA's cut grade system and rounding system for proportion numbers are !#$#@.

This diamond could have been an ideal cut diamond by lowering the pav angle a bit. But the cutter did not to maintain 2.0c+ weight.

 

[bmfang]

That stone was cut to retain weight. Using a quick and dirty method to determine if the cutter cheated the stone, if it were cut to ideal proportions, it should have weighed in at 1.99cts. The temptation was too strong for the cutter to retain weight so that it could cross over the 2ct mark.

 

[ChristineRose]

Most stones nowadays are cut right to the border of GIA XXX.

The X cut rating was based on showing a whole bunch of people a whole bunch of stones. Some people liked the "badly" cut stones better. That's why the rating is so broad. There is no guarantee that you will like this stone better than a "good" stone, of course, so it's a bad choice for an online purchase.

The HCA though has been criticized for bias towards a particular type of stone that some people like. This particular stone is way down on the other end of what the HCA likes.

 

[lucida]

Wow, ok. In the past I'd been told to only consider GIA XXX diamonds and now this
So you don't suggest it and it would not shine like the other stud (with a holloway of 1.9)? If so, I'm glad that I didn't go through with it. I was willing to pay 18k for both, thinking that I was getting the best possible diamonds.

So the "X" needs to be enclosed in the solid line to be guaranteed that it'll shine like crazy - am I right?

Thank you all for your input.
Thanks.

 

[ChristineRose]

The purpose of the HCA is to narrow down the selection of online stones to those that are most likely to be attractive. That's it. It doesn't account for funky tastes and all the ways a good cutter can tweak a stone, and it is not a guarantee of anything. It is quite possible for a stone with a bad Holloway (maybe not a 6 bad) to be nicer than a stone with a good Holloway. It's just not nearly as likely as the opposite.

When you find a promising stone, you ask for more info, such as an Idealscope. At this point it becomes a tradeoff between more expensive dealers who will give you a lot of information, and cheaper dealers who may be less helpful.

If you want a guarantee of a gorgeous stone, talk to one of the recommended dealers who specialize in gorgeous stones. They will cost you a bit more though. Otherwise, be prepared to sort through a few of them.

 

[bmfang]

No such thing as an iron clad guarantee. More like a high probability if the X falls within the boundaries of both the solid and broken lines that the stone should be a good performer. There is always the chance that due to inclusions or fluorescence that a stone that sounds good on paper can look like a dog's breakfast in reality.

 

[John P]

Wow, ok. In the past I'd been told to only consider GIA XXX diamonds...

Some more perspective may be interesting.

Right now there are 807,000.- GIA graded round brilliants (0.30-3.00ct, D-M, FL-SI2) listed on the industry's largest wholesale trading platform.

How many of those 800,000+ earned the lab's topmost cut judgment of GIA Excellent? ...67%
When you limit that judgment to Triple-EX ...55%

Compare to GIA D color, no fluor...11%
Compare to GIA FL-IF clarity...7%
Pretty crazy, no?

Now consider: 54% of these 807,000 diamonds are graded between FL-VS2 in clarity. In visible terms many or most will be clean to the average eye without a loupe. And yet, depending on the VS-VVS-F grade, one might be 70% more expensive than a twin of the same weight, color and cut.

Meanwhile: The 67% of diamonds which carry "GIA EX" on their grading report might be presented as "the same" in cut-quality to a layman, even though they span a tremendous range of variable appearances and performance-quality levels - most of which slide toward the lenient side of the scale.

Most stones nowadays are cut right to the border of GIA XXX.

Precisely.

For anyone interested, there's upstream insight in this post about the bizarre pricing-dysfunction - relative to cut-quality and GIA grading - persisting between miners, cutters and - ultimately - those of you who are end consumers.
https://www.pricescope.com/communit...rity-and-prices.228480/#post-4125381#p4125381

 

[flyingpig]

So the "X" needs to be enclosed in the solid line to be guaranteed that it'll shine like crazy - am I right?
Thanks.

If the "X" is enclosed in the solid line, it means the diamond may qualify for AGS0, based on the proportions alone. In most cases, it is certainly better than a borderline GIA ex.

However, many PSers go one step further and use the following guide
Table 54-58, Depth less than 62.3, Crown 34-35, Pav 40.6-40.9

Try to find a diamond whose proportions fall within the above ranges AND score less 2.0 in HCA

They are many cut quality screening tools. GIA cut grading is one. AGS proportion chart is another one. HCA score is useful, so is the ideal proportion ranges. I always use all four, because no single tool is perfect. These are SCREENING tools.

NOw, once you are decided on stones, you need to request ASET or Idealscope images. With the budget and carat size you are working with, I would definitely ask for ASET image. IS image alone is not sufficient.

 

[Texas Leaguer]

So the "X" needs to be enclosed in the solid line to be guaranteed that it'll shine like crazy - am I right?
Thanks.

If the "X" is enclosed in the solid line, it means the diamond may qualify for AGS0, based on the proportions alone. In most cases, it is certainly better than a borderline GIA ex.

However, many PSers go one step further and use the following guide
Table 54-58, Depth less than 62.3, Crown 34-35, Pav 40.6-40.9

Try to find a diamond whose proportions fall within the above ranges AND score less 2.0 in HCA

They are many cut quality screening tools. GIA cut grading is one. AGS proportion chart is another one. HCA score is useful, so is the ideal proportion ranges. I always use all four, because no single tool is perfect. These are SCREENING tools.

NOw, once you are decided on stones, you need to request ASET or Idealscope images. With the budget and carat size you are working with, I would definitely ask for ASET image. IS image alone is not sufficient.

I agree with this guidance. The reason more cut quality vetting is necessary for GIA diamonds is not only the fact that the top grade is very broad, but because it is a "table based" system that uses rounded and averaged inputs to peg grades on predefined grading tables and charts. Using those inputs in the HCA tool, a similar table based system, will likewise obscure important aspects of light performance.

And faceting precision (aka optical precision) is also very important to understand if you are interested in maximizing beauty. Just as having one foot in boiling water and the other in a bucket of ice does not make for a comfortable average temperature, large variations in cutting angles do not make for optimal light performance, even if the averages hit sweet spots on grading tables.

ASET fills in much of the gap in understanding about light return, light leakage, contrast, and also sheds light on facet precision.