New Gia diamond cut grading system

[valeria101]

Date: 1/8/2005 5:21:50 AM
Author: lostdog
What's the impact on the market, do you think?

It's hard not to be cynical and conclude that consumer's options for buying the better grade stones just got visually smaller or more expensive or both.

I don't know all that much about these things... that was just a hunch. It would be a pitty not to follow an interesting discussion !

It's not like ideal and branded cuts are GIA's new, new thing - these are tried and true selling points by now. There seems to be every possible set of choices among the 50 or so diamond cut brands listed: havy, spready, anywhere between 150 and 8 facets... Anything goes.

Looking at how current ideals work: round ideals already command a premium although what exactly "ideal" means and which is more ideal is not as much recognized as the empty word. No matter how far or close to the current ideal standard(s) GIA's top grade is, it targets the current "ideal" price point, whatever that is. Will the new grades make higer "ideal" pricess spill over across the board ? Over night ? Don't think so. There is no current shortage of ideals,as far as I know (which is not too far). There's a shortage of cheaper ideals, and of buyers asking for one. So that's where the room for growth is, I would think. GIA1 is not another HOF or Lucida... maybe just once or twice by accident. And GIA has the market clout to prop demand...

With this in mind, I can't be that cynical. Diamonds are no meant to be cheap anyway.

Prices didn't need any excuse to go up until now, so the cut grade may just make the good old trend a bit easier to prop over the counter. Product differentiation supporting price increase doesn not sound innovative at all. With it's weight, GIA can make this happen market-wide, not just in the top price range. GIA already has allot of consumer recognition, so their cut grades will make cut quality that much more known and demanded overall.

How much of a revolution this is yet another question... the ideal cut clout will lift more than just one price hyke, and not just short term, I would think.

As is, prices for the same weight-color-clarity are already very different from one stone & shop to the next. If this variation is only partially due to pricing better cuts differently, than this can only dull the price impact of GIA grades over time. Once diamonds are cut on purpose to fit the grid and customers' recognition of the grades, the price impact can only be further melted into the usual trend.

I am quite curious how many GIA top cuts can there be anyway. This depends on how inclusive is the GIA1 grade relative to current market standards, this I do not know how to pin down.

Why just GIA1 ? Well... AGS1 and below didn't get that much attention, as much as I know - only the top grade did. I expect the same to happen with GIA's top grade. Otherwise whoever buys into the lower grades would actually need to understand what they mean aside recognizing GIA's authority. Well... that may happen on Pricescope. But there are many more diamonds out there.

Already said way more than I know !

 

[Garry H (Cut Nut)]

People do not only buy D iF

People do not only buy Ex Ex

 

[valeria101]

Date: 1/9/2005 5:23:12 AM
Author: Garry H (Cut Nut)
People do not only buy D iF

People do not only buy Ex Ex

Sure so... only it seems that many, many more go for (or at least consider as refference) those "Ex"-s than D/IF, no ?

 

[Fleimstaler]

Hi Garry.

I read your comment that the stone RD 16 was down graded pecause of "Good" polish. I read again what GIA wrote and could not find it on the G & G article.

Quote

"This diamond''s grade is determined by brightness, scintillation, and polish.

Although no one of its proportions would necessarily cause its brightness or scintillation to perform poorly, the combination of this particular set of proportions leads to increase darkness in the pavillion mains"

Unquote.

As my knowledge of english is very unaccurate and therefore I might not understand perfectly the meaning of a sentence what I understand is as follows:

All proportions taken singularly are all right, but as a set, " the combination of this particular set of proportions....."

they do not perfomr properly and therefore the stone is down graded.

As far as I can understand is "this particular set of proportions that leads to........ a down grade, as they "lead to increased darkness of the pavillion mains"

The cause of down grading this stone seems to me to be the set of proportions that cause darkness in the pavillion mains.

Polish cannot cause darkness in this case. It may be a concause, but definitly not the main as there is no mention of it, but the set of proportions are clearly mentioned.

The question is: what is the difference from this particular set of proportions, that in stone N. RD16 cause darkness but, the same set of proportions in stone N. RD01they do not cause it? Not only proportions are the same but all measurments are the same.

GIA must have found a difference other than polish in these two stones, because every gemmologist in any country and without the need for a new grading system, would notice that one is properly polished and the orther is not and would grade it accordingly.

Do you think that GIA would just come out and say: we can differentiate two stones by their lack of polish, and is what we found and is our new Grading system? Would this be so new?

There must be a difference somewhere that does not show up but they can see.

How can you see this difference? This is the point that must be answered to, and this was my quest when started this thread and hoped to have qualified comments on it.

I gave my own experience openly and hoped to discuss it freely. Nothing more nothing less

Thanks and rgds.

Fleimstaler

 

[Garry H (Cut Nut)]

Date: 1/9/2005 6:45:56 AM
Author: Fleimstaler
Hi Garry.

I read your comment that the stone RD 16 was down graded pecause of 'Good' polish. I read again what GIA wrote and could not find it on the G & G article. it is in the text and said at Basel GemFest, and it is commonsense - it is mentioned on the pull out chart.

Quote

'This diamond's grade is determined by brightness, scintillation, and polish.

Although no one of its proportions would necessarily cause its brightness or scintillation to perform poorly, the combination of this particular set of proportions leads to increase darkness in the pavillion mains'

Unquote.

As my knowledge of english is very unaccurate and therefore I might not understand perfectly the meaning of a sentence what I understand is as follows:

All proportions taken singularly are all right, but as a set, ' the combination of this particular set of proportions.....'

they do not perfomr properly and therefore the stone is down graded.

As far as I can understand is 'this particular set of proportions that leads to........ a down grade, as they 'lead to increased darkness of the pavillion mains'

The cause of down grading this stone seems to me to be the set of proportions that cause darkness in the pavillion mains.

Polish cannot cause darkness in this case. It may be a concause, but definitly not the main as there is no mention of it, but the set of proportions are clearly mentioned.

The question is: what is the difference from this particular set of proportions, that in stone N. RD16 cause darkness but, the same set of proportions in stone N. RD01they do not cause it? Not only proportions are the same but all measurments are the same.

GIA must have found a difference other than polish in these two stones, because every gemmologist in any country and without the need for a new grading system, would notice that one is properly polished and the orther is not and would grade it accordingly.

Do you think that GIA would just come out and say: we can differentiate two stones by their lack of polish, and is what we found and is our new Grading system? Would this be so new?

There must be a difference somewhere that does not show up but they can see.

How can you see this difference? This is the point that must be answered to, and this was my quest when started this thread and hoped to have qualified comments on it.

I gave my own experience openly and hoped to discuss it freely. Nothing more nothing less

Thanks and rgds.

Fleimstaler

The proportions are indeed not the same.
There are more accurate proportions in the GIA Fire article Fall 2001 for these stones - they are in brackets on my post above.
The table is 1% smaller.
The crown angle in stone #1 grade is 34.3 #2 is 33.8
Pavilion angles #1 40.6 and #2 40.4

all of these proportions indicate the need for shorter lower girdles
In the Foundation article they quote 75% for both - in the Fire article #1 is 81% and #2 is 76%.
it is apparent in the photo's and the Diamcalc model confirms the numbers.

This can help to understand?
http://www.ideal-scope.com/manuf_fine_tuning.asp

 

[Garry H (Cut Nut)]

Edited - link was broken
http://journal.pricescope.com/Authors/2/Garry-Holloway.aspx

I am sorry it has taken so long to publish this
If you wish to discuss the article could you please do so at this Forum topic:
https://www.pricescope.com/community/threads/discuss-review-of-gia-foundation-article-posted-in-the-journal.23588/

 

[Fleimstaler]

Hi Gary,

thanks for the answer.

Fleimstaler

 

[Fleimstaler]

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[Fleimstaler]

Hi Neal

Comments will follow.

Fleimstaler

 

[Fleimstaler]

Hi Neal.

As I promised I sent some gemprint photos of different round cut diamonds.

Please take a look at photo N. 04. This is a photo of brilliant cut diamond graded for proportions and finish VERY GOOD.

Now take a look of photo n: 01. This photo does not belong to me and I do not know whose photo it is as it was torn out of catalogue in Japan by a friend of mine and brougt it to me as it is.

This cut diamond has perfect reflections by all means. I would like to have one like this but I do not have one. Do you see the difference from photo N. 01 and 04?

The others are the reflections of round cut diamonds that have been graded EXCELLENT.

The first studies on gemprint like reflections of cut on gemstones, was done Germany in 1925.

As you can see through these photos a great amount of information can be retieved from them.

Rgds.

Fleimstaler