How can a consumer select a fancy shape?

[Karl_K]

Date: 3/25/2010 4:13:43 PM
Author: QueenMum

Date: 3/25/2010 4:06:31 PM

Author: kenny

If I was a vendor and customers educated by your charts didn't buy my diamonds I'd work to discredit your charts, or introduce doubt about them.

Kenny, you didn't follow the AGA chart when buying an Octavia... and your Octavia is beautiful.

The case that proves the point....
Run it through the AGA charts.
If I believed in them it never would have been designed.
Fancies can not be defined by numbers on a chart.
The first fatal flaw in the charts is that spread is not proportional to depth in step cuts and many other fancy cuts.
The second fatal flaw is that the best performance in many fancy cuts is on the deep end not the shallow end.

 

[Stephan]

Kenny, I highly respect Karl.
The Octavia is probably a ''never seen before'' beauty.
I wouldn''t buy it because I prefer long flashes in step cuts (like in an EC) and because of the spread factor. Indeed, paying a premium for a brand while having a smaller looking diamond is not my cup of tea.
If you respect the AGA chart when buying an Asscher, I think it will look bigger than an equal weighted Octavia, correct me if I''m wrong.

Karl was genial enough to create a cut that both pleases the consumer ... and the rough.
That is my conviction.

 

[pancake]

I'm a consumer, very much a novice, and I've only ever bought 1 diamond.

In general I am a very thorough and diligent researcher; my line of (non-diamond related!) work is heavily "evidence-based" and driven by this, and I think I'm diligent (read: obsessive) and thorough (read: anal) outside of work too.

My one diamond purchase was an EC for my engagement ring. I trawled reputable internet sources (PS, but also others) for probably a hundred hours before embarking on buying my own. I was all set to look at ASETS and be very "evidence-based" in my diamond research.

However, in the end I went with ERD who were - at that stage - not providing ASET. I was given some photos, a lot of discussion (phone and email) and a Sarin. I contradicted myself quite a bit in the process, as I had been very keen to make the search as technically rigorous as possible - but ended up choosing a stone through a vendor who I trusted to be my "eyes" (and more informed eyes than mine). (Aside: I did know that the stone sat in the AGA 1A class for all but one parameter). My EC is not large but it is a knockout!

I have no doubt that had I gone with eg. GOG that I would have also found myself an incredible stone (and I found Sarah absolutely fantastic in preliminary discussions, which were eventually interrupted by finding a stone at ERD).

I don't really know what point I am trying to make here, except to say that I think that it is possible to find a wonderful stone without the tech tools, provided that the vendor is scrupulous, committed and on the same wavelength as the buyer.

And also, I guess - from another point of view as an "expert" in another highly technical field - that I am not entirely sure of the value of technical information in the hands of laypeople. (disclaimer: obviously this is different for experts such as many here on PS)

 

[Stephan]

Date: 3/25/2010 4:22:42 PM
Author: Karl_K
The first fatal flaw in the charts is that spread is not proportional to depth in step cuts and many other fancy cuts.

Correct, same thing happens with Paul''s princesses, by the numbers they can look slightly deep, but they have better spread than other ''shallower by numbers'' princesses.
Yet I sill think most of the squarish fancy cuts are cut for weight retention, even if some achieve real beauty.

 

[Karl_K]

Date: 3/25/2010 4:25:12 PM
Author: QueenMum


If you respect the AGA chart when buying an Asscher, I think it will look bigger than an equal weighted Octavia, correct me if I'm wrong.


Karl was genial enough to create a cut that both pleases the consumer ... and the rough.

That is my conviction.

You are wrong on the spread.
Spread is not proportional to depth in step cuts and many other fancies.
It has the same spread as common asschers that make 1a-1b on the charts.
It will also look bigger from better light return and controlled reflections.

Sadly wrong on yield also which is why they will never be cheap.

 

[kenny]

QueenMum, frankly I bought our ACA, Solasfera, generic asscher and the Octavia (and three other rounds) without consulting the AGA chart.
I didn't feel the need to myself.
I felt confident in the light performance of my choices before and after the sales.

I support its existence and use as a tool for shoppers of of the fancy cuts like pear, radiant marquise etc.
Is it perfect or does everyone agree on the data?
No, but it's better than nothing.

Shopping for fancy cuts online is difficult.
I'm hoping Paul started this thread because he has some clever new tool up his sleeve.

 

[Stephan]

As many said, in real life vision is so important.
Funny example: some people love table glare, other hate it.

 

[Rockdiamond]

Date: 3/25/2010 3:39:09 PM
Author: mrskantz
Is an ASET even a good sign of how good the diamond will look?

Doesn''t it just measure how light reflects when looking straight down at the diamond?

BINGO!!!

Take a single snapshot of Joe Shmoe, and he looks like Cary Grant- or vice versa.
An ASET looks at a diamond one way, while in reality we look at diamonds in literally, millions of angles and lighting combinations.

 

[Rockdiamond]

Date: 3/25/2010 3:55:27 PM
Author: oldminer
The AGA Cut Class charts are good screening tools for fancy shapes. One must choose an outline which pleases them. This is very personal and not part of the function of screening by parameters. The charts will help you target stones which look reasonably large for their weight because better quality stones are not overly deep. Or it will downgrade amazing stones that look very large for thier weight (with no downside) because they are more shallow than 1A. The charts will help consumers avoid girdles which are overly thick or overly thin. Thin girdles can contribute to unforeseen durability issues and thick girdles contribute to excess weight and correspondingly less visual size. The preceding statement is a generalization. If we''re talking about Radiant Cuts, for example, they actually have 8 separate girdles. There are many stones with EX thick girdles yet have nice spread. Likewise thin- it''s far to general to say GIA calling a girdle thin means a diamond is more likely to break. Same for the next statement about shallow crowns. Shallow crown diamonds may have durability issues, especially near pointed ends in pear and marquise shapes. Steep crown diamonds are not so problematic. Tables within certain ranges of width allow for maximization of sparkle and fire around the crown. Overly large tables may hurt light performance and overly small tables will not look like the kind of diamonds dealers agree are premium, fine cuts. All due respect David, but I don''t believe you''ll find many dealers endorsing the AGA chart- how many dealers were involved in drawing the charts? The length to width ratios are also non-grading suggestions based on dealer preferences. Consumers are free to choose any length to width ratio they personally prefer.

The charts take into account what experts know intuitively about diamonds, but what they have generally avoided in communicating to customers. The more blind diamonds are, the easier it is to sell the less than fine stones for premium prices. Diamonds and diamond dealers are tricky as all small merchants are. Try to buy oriental rugs at an Indian or Arabian bazaar and see how knowledge is the basis for making a good deal. The more you know, the better a deal you may make.

I think the criticism here is based on misunderstanding of what the AGA system does and what is does not do. People have said for a long time that they don''t do what they are supposed to do, yet consumers use them and find great make fancy shapes. If you go through the parameters for round diamonds, you''ll find the GIA and AGS0 stones are in the 1A-1B categories. I did this before GIA and AGS did it and I believe I did it right. The fancy shapes which make 2B and higher grades are all worthy of consideration. Cutters do not go out of their way to make 1A fancy cuts, but of those I''ve seen, they appear to be excellent looking. Cutters are very smart and do cut great looking diamonds when they are able to use such fine proportions. Why would they cut an ugly diamond with such excellent proportions? They wouldn''t.

The AGA system helps consumers eliminate diamonds which have obvious parametric problems. It helps those who want very fine stones to know where the sweet spots are in a gradual way. There are many great diamonds in fancy shapes which are 2B and better and with that in the consumer''s mind, I still believe the AGA system is very helpful to their search.

Those who disagree usually are those who are hoping to sell fancy shaped diamonds which have durability or visual size issues that a novice consumer would not understand unless they use the AGA system for screening. This sort of bias is understandable by anyone reading this, but just because eight or ten critics say the system is worthless, does not make it so. In fact, the noise making implies to me the uncomfortable elements of truth which some might prefer to just go away are clearly evident to consumers in the AGA system.
The preceding statement is just an overly broad, yet direct insult to any dealer who disagrees with the charts. I don''t recall seeing many ( if any) dealers advocating the their use. I enjoy this discussion- and I feel it''s relevant. This is NOT because I''ve been deluged with consumers asking for "1A" stones- I don''t recall any consumers even mentioning the charts

If Paul would cut AGA 1A ovals or pear shaped diamonds and market them he''d find that there are consumers who would love his production. It would take a lot of money and courage to buck the mainstream, but with enough staying power a cutter could carve a super niche with finely cut, beautiful diamonds which closely fit what I have deduced at top cut diamonds. No, I''m not the GIA, but this is the work of many years and based on observations of many diamonds. I have always asked for constructive advice and a few here have shared some with me. I have changed the charts a few times in order to do the job better. Saying they are worthless is just not helpful to anyone and in my opinion is not the best advice.

Here''s what I find particularly insidious about this: If the charts are "right", then I ( and other dealers) must forget about looking at actual diamonds, and tell our cutters only to show me "1A" stones.
We must throw away years of experience to trust what AGA says.
The charts are not practical - as I''ve already pointed out, false negatives can be very damaging.

Paul- I applaud the thread- although we may not see eye to eye on some issues, I did agree with a lot of what you wrote.
I will not quote you or put meaning to your words- but in my interpretation, I found a lot to agree with.
Have a good night''s sleep!!

 

[WinkHPD]

Date: 3/25/2010 4:43:34 PM
Author: Rockdiamond

Date: 3/25/2010 3:39:09 PM
Author: mrskantz
Is an ASET even a good sign of how good the diamond will look?

Doesn''t it just measure how light reflects when looking straight down at the diamond?

BINGO!!!

Take a single snapshot of Joe Shmoe, and he looks like Cary Grant- or vice versa.
An ASET looks at a diamond one way, while in reality we look at diamonds in literally, millions of angles and lighting combinations.

Not Bingo, not even close. You take an incorrect statement and twist it to suit you. Shame on you!

The ASET measures NOTHING! We have discussed this before and I believe you know it by now, which is why I am both shocked and disappointed in your comment.

The ASET tells you where the light that you are seeing is coming from. Period. The light that is coming from 0 degrees to 45 degrees from the horizon is seen as green in the ASET. That light coming from 45 degrees to 75 degrees is seen as red in the ASET. The light that is obstructed by the viewer, 75 degrees to 90 degrees, is seen as dark blue in the ASET. Leakage is shown as either black or white depending on whether you are using a white or black background.

It is perfectly easy in the original ASET to tilt the stone at any angle and assess what you are seeing. You know these things already. The ASET is most normally used to look at a diamond and see where the light is coming from, it tells us volumes about the potential of the diamond, it does not matter what shape.

For example, when I see an ASET like the one on the left in this picture, I do not need to be a rocket scientist to know that it has the potential to be a lifeless lump of crystallized carbon, and it is. On the other hand, the ASET on the right is full of red, which is likely to be the most intense light, coming from overhead, with a respectable mix of green and a well defined obstruction pattern to provide contrast and most likely, scintillation as the obstructed facets light up as the stone is moved and other facets become obstructed. It is this very on/off blinking that makes diamonds more interesting. I know from looking at this pattern that the diamond has great potential.

While looking at fancies is nowhere near as easy to judge as looking at rounds, it should not take rocket scientist to see if there is a good mix of red and green and if there is some type of pattern of blue, or is it all a muddle in one place. Is there more black than green or red? If so, I have a pretty good idea of that "gem''s" potential.

You do too!

I was going to finish reading the thread before making a comment to assist mrskantz in understanding the ASET better, but your post put me in a "do it now" mood. Your comment is pure balderdash.

Wink

 

[Hest88]

Date: 3/25/2010 4:43:34 PM
Author: Rockdiamond

Take a single snapshot of Joe Shmoe, and he looks like Cary Grant- or vice versa.

Oh gosh. So why haven''t I taken any photos that make me look like Angelina Jolie?

 

[mrskantz]

Date: 3/25/2010 6:37:33 PM
Author: Wink

Date: 3/25/2010 4:43:34 PM

Author: Rockdiamond

Date: 3/25/2010 3:39:09 PM

Author: mrskantz

Is an ASET even a good sign of how good the diamond will look?


Doesn''t it just measure how light reflects when looking straight down at the diamond?

BINGO!!!


Take a single snapshot of Joe Shmoe, and he looks like Cary Grant- or vice versa.

An ASET looks at a diamond one way, while in reality we look at diamonds in literally, millions of angles and lighting combinations.

Your comment is pure balderdash.


Wink

Balderdash...I love that game

Thank you for your explanation. I see a lot of people talking about it and judging solely by it when one can do just as good by slowly rotating the diamond under light and counting the amount of "flashes" per quadrant. The ASET seems like a good tool but only tells 1/4 of the story.

I''d really like Paul to comment on the GIA report I posted for my diamond. Of course only gives a little insight, but it seems to line up to his numbers better and boy does my diamond looks like the Superbowl stadium at night for opening kickoff when it is rotated.

 

[Rockdiamond]

Wink, my apologies. I did not consider the use of the word "measure"- although how the ASET is commonly used here seems a lot like measurement to me.

My point is that ASET photos show a single perspective, light coming from a single direction.

I have no doubt whatsoever that your assessment of the stone on the left has merit- but if I was called upon to comment on it, I'd still want to see the stone.
Or a good series of digital photos- which would be far more illuminating than ASET IMO

Personally, I would never use ASET to either select, or reject a diamond.

 

[ChunkyCushionLover]

Date: 3/25/2010 6:37:33 PM
Author: Wink

Date: 3/25/2010 4:43:34 PM
Author: Rockdiamond

Date: 3/25/2010 3:39:09 PM
Author: mrskantz
Is an ASET even a good sign of how good the diamond will look?

Doesn't it just measure how light reflects when looking straight down at the diamond?

BINGO!!!

Take a single snapshot of Joe Shmoe, and he looks like Cary Grant- or vice versa.
An ASET looks at a diamond one way, while in reality we look at diamonds in literally, millions of angles and lighting combinations.

Not Bingo, not even close. You take an incorrect statement and twist it to suit you. Shame on you!

The ASET measures NOTHING! We have discussed this before and I believe you know it by now, which is why I am both shocked and disappointed in your comment.

The ASET tells you where the light that you are seeing is coming from. Period. The light that is coming from 0 degrees to 45 degrees from the horizon is seen as green in the ASET. That light coming from 45 degrees to 75 degrees is seen as red in the ASET. The light that is obstructed by the viewer, 75 degrees to 90 degrees, is seen as dark blue in the ASET. Leakage is shown as either black or white depending on whether you are using a white or black background.

It is perfectly easy in the original ASET to tilt the stone at any angle and assess what you are seeing. You know these things already. The ASET is most normally used to look at a diamond and see where the light is coming from, it tells us volumes about the potential of the diamond, it does not matter what shape.

For example, when I see an ASET like the one on the left in this picture, I do not need to be a rocket scientist to know that it has the potential to be a lifeless lump of crystallized carbon, and it is. On the other hand, the ASET on the right is full of red, which is likely to be the most intense light, coming from overhead, with a respectable mix of green and a well defined obstruction pattern to provide contrast and most likely, scintillation as the obstructed facets light up as the stone is moved and other facets become obstructed. It is this very on/off blinking that makes diamonds more interesting. I know from looking at this pattern that the diamond has great potential.

While looking at fancies is nowhere near as easy to judge as looking at rounds, it should not take rocket scientist to see if there is a good mix of red and green and if there is some type of pattern of blue, or is it all a muddle in one place. Is there more black than green or red? If so, I have a pretty good idea of that 'gem's' potential.

You do too!

I was going to finish reading the thread before making a comment to assist mrskantz in understanding the ASET better, but your post put me in a 'do it now' mood. Your comment is pure balderdash.

Wink

Good post Wink, I haven't played balderdash in a while but its funny seeing it used as a noun.

The newest AGS ASET camera which I beleive is being used most often by PS vendors these days offers a video feed directly to a computer. It was designed with video in mind and not just the static snapshots.
It is upsetting that this latest "most modern" ASET camera doesn't provide the option to take white background backlit images, and also that so many vendors have trouble controlling the office lighting and calibration of their cameras. There is somewhat of a steep learning curve in learning to operate the black background ASET, whereas the original was much easier to use.

If I had the time and incentive I would design an enclosed chamber (like the presentation ASET) with backlighting and a white background and place the diamond on a tiltable platform and rotate the diamond in several directions to take a video. This should remove a great deal of limitations that occur with the use of the ASET, even AGS in their PGS uses a weighing of 5 tilt positions (the most heavily weighted is faceup).

I beleive once a vendor overcomes the learning curve of the photography and lighting setup the use of ASET distinguishes them from the hundreds of other vendors selling virtual diamonds. GOG and WF are two vendors that take consisantly good ASET images in fancy shapes (not just princess cuts) and I beleive this really helps them increase their sales and distinguishes them from their competitors.

This slideshow is in my mind useful in describing to trade and consumers the design and application of the ASET http://www.americangemsociety.org/uploads/ASETTheory-709.pdf

 

[Rockdiamond]

ccl- not to start another argument, but I believe that balderdash is a noun in the Wink's post

If I was writing as a consumer I can see a lot of the points you raise.
But I can honestly say that I would prefer that effort expended in technology for sellers of diamonds- or any item on the web, it would be photos and video in natural , or even high intensity lighting. Without the restriction of ASET.
As tradesperson I share your admiration for those sites who really have used the technology very well for their clients.

I admire Wink, and his site- please don;t misunderstand my points bout ASET to be a criticism of sites who use ASET- because in those cases it always comes along with good digital photos, AND first hand observation by well respected sellers.
Which is entirely different form trying to judge stones based on ASET when they are can't be judged first hand- which is the strongest argument FOR ASET, I know.

I'd still like to see good photos of the ugly stone on the left in the ASET- just for fun.

 

[Rockdiamond]

I have no problem seeing the implied lighting patterns, and their import, looking at the diamond on the right in Winks post.
Stone on the left?
The patterns have less meaning as it''s almost too weird to be called a "brilliant cut".



This is my best try at taking an ASET photo.
What does it tell us?
I ask this in earnest.
I''m totally clear that if I wanted an ASET analyzed, experts ARE here.

 

[ChunkyCushionLover]

Date: 3/25/2010 8:06:46 PM
Author: Rockdiamond
I have no problem seeing the implied lighting patterns, and their import, looking at the diamond on the right in Winks post.
Stone on the left?
The patterns have less meaning as it's almost too weird to be called a 'brilliant cut'.



This is my best try at taking an ASET photo.
What does it tell us?
I ask this in earnest.
I'm totally clear that if I wanted an ASET analyzed, experts ARE here.

Stone on the left has short LGFs and a culet and has an appearance similar to that of an OEC albeit a poorly cut one.

To improve your image should put white paper between the light source and the diamond, both to provide a backgound for contrast and to prevent direct light from hitting the diamond and scope, the best images come where the diamond is lit from behind with mild diffuse light not sharp directional light. Try to prevent direct lighting from hitting the scope and diamond from the side.

Ignoring the tweaking needed it seems like a pretty nice vintage faceted cushion (I see some leakage(clear) but it also has a lot of areas which gather light from overhead(red)). I can see already you are very good at focussing through an ASET scope

.

Retake the image with the white background and then what I suspect is the comments may be quite positive on the cut of this cushion.

Not sure what is going on in the bottom right corner of the girdle is that a chip, lint or an optical illusion?

 

[Circe]

Date: 3/25/2010 2:34:50 PM
Author: Rockdiamond

...

False negatives can be just as damaging as false positives as they can prevent the proper stone from being considered.


The ACA charts have this same problem- as well as another, which also bothers me greatly.

The ACA charts place ratings on stones.

A 1a is ''better'' than a 2a- right?

Well, if you''re the consumer who just bought a stone you LOVE, then plug in the numbers to find you bought a ''less than optimal'' stone, it can hurt. It might actually place a seed of doubt in the consumer''s mind with no basis whatsoever in fact. But a grading system like 1a, 2a etc sounds ''factual''

Again, false negatives can be just as bad as false positives.


....

Snipping since I don''t know how to highlight - and BRAVO to you as well, David, for making a very important point.

When I bought my pear, I was delighted ... until I read the chart and saw that the 64.5 depth stuck it firmly into 2B class. I second-guessed it for ages and even posted a thread here looking for reassurance despite Lorelei and FB''s (and other expert PS''rs - sorry for being forgetful, guys) assurances that that was fine, that was good, that might actually help to reduce bow-tie (which, for the record, after having lived with this stone for a bit, I think it does).

A qualified salesperson to help me in terms of choice and reassurance would have been a boon: instead I gambled on the best rough numbers and the best price and the best return policy (sad that it has to factor into the equation, but, hoo-boy, did it). I believe I came up lucky ... but for a bit there afterhand I was uncertain, and that''s a shame. I believe it''s important to "trust your eyes," but it would have been fantastic to have had an expert''s eyes to trust as a matter of course in the biz, as opposed to a vague chart and my own inexperienced-with-this-shape set of peepers.

The thing is, while we have a few specialists in H&A rounds, and Mark at ERD for cushions, JBEG for old cuts, Karl for asschers ... I am damned if I can think of any stores that specialize in pears, marquis, or ovals. Anybody wanna fill a niche?

 

[Paul-Antwerp]

Date: 3/25/2010 2:34:50 PM
Author: Rockdiamond
BRAVO Paul!!!!

Your points are well thought out, and totally relevant.
I could not agree more.

To address a few points that have already come up:

Cinna- I agree with Karl, you did get lucky- but I''m sure your stone is a knockout!
You mentioned using a highly regarded appraiser.
To me, that is closely related to the points raised about ASET.
Here''s how: If the appraiser LOVES the diamond, that is ZERO guarantee the consumer will.

The main problem these type of tests is that they may produce false positives, or false negatives.
I''ve heard that term so many times- ''use this or that tool for rejection''

False negatives can be just as damaging as false positives as they can prevent the proper stone from being considered.

The ACA charts have this same problem- as well as another, which also bothers me greatly.
The ACA charts place ratings on stones.
A 1a is ''better'' than a 2a- right?
Well, if you''re the consumer who just bought a stone you LOVE, then plug in the numbers to find you bought a ''less than optimal'' stone, it can hurt. It might actually place a seed of doubt in the consumer''s mind with no basis whatsoever in fact. But a grading system like 1a, 2a etc sounds ''factual''
Again, false negatives can be just as bad as false positives.

Another aspect to this which is so very difficult is the lack of trust placed in diamond sellers.
There may be very good cause for this disdain, if we use ''averages''- but this is another area where false negatives can hurt the consumer.

I have enough PS scars no know NOT to refer to ASET as a ''gimmick''- but there are many sellers who have great ability to select and provide fancy shaped diamonds that might use the word.

But Kenny''s attitude ( feeling some sort of definitive test for fancy shapes is desperately needed) points out another common attitude here on PS.
There''s a mistrust of sellers- as well as a feeling that ''prosumers'' are effective at assisting consumers selecting fancy shapes.
Put this together and sometimes it can get antagonistic....which is a shame, especially considering how well PS is monitored- resulting in an atmosphere where I believe the regular posters ( both tradespeople and prosumers) are ALL genuinely interested in helping consumers.

David,

I took my time to read and re-read what you said. A lot of it is off-topic, I must say.

As long as we are discussing rounds, which is not the topic here, you are still not accepting that the rejection-tools used (lab''s cut-grade, HCA, ideal-scope, ASET) are indeed valid rejection-tools for brightness. In that way, the number of ''false negatives'' is extremely limited, when using these tools correctly.

Your defense of these ''false negatives'' is the same as coming up for the ''human'' rights of that poor neglected diamond. While very noble, this defense is not to the benefit of the consumer in any way.

As far as the real topic of this thread goes, you are coming up with arguments that are off-topic and that I definitely did not raise. You may have your beef with the AGA-charts (I do too), and you may even express that you are not using ASET because you find it too complicated and you do not understand it (the latter is clear), but it has no relation to my original post, which depicted the situation of a consumer, trying to make a first selection from a huge virtual list of fancy shapes. They do not have the data to use the AGA-charts, nor do they have ASET''s, not even a cut-grade of a lab. You might agree with me that the task for this consumer is close to impossible, but could you please limit your comment then to agreeing with it, and refrain from a post that turns my observation into a complete criticism of PS.

Live long,

 

[Paul-Antwerp]

Date: 3/25/2010 3:29:14 PM
Author: QueenMum
A part of the solution could be that every diamond is scanned.
Paul and Jonathan already do that, and I applaud them both for that.
But one problem remains, it is the .gem viewer.
Gem Advisor looks way too unreal.
DiamCalc looks much more realistic, but it isn''t for free.
It would be nice to have a limited DiamCalc version, just to view scanned diamonds without the possibility to modify the proportions.
I''m sure potential buyers are ready to pay a premium for diamonds visible in DiamCalc, and this premium could help dealers to finance the project with Octonus.

Considering that the majority of fancy shapes offered for sale are virtual, getting a scan of every stone is not feasible. And it still does not solve the challenge of the consumer looking at the huge virtual list without a clue where to start.

Live long,

 

[Paul-Antwerp]

Date: 3/25/2010 3:41:25 PM
Author: kenny

Date: 3/25/2010 3:39:09 PM
Author: mrskantz
Is an ASET even a good sign of how good the diamond will look?
Doesn''t it just measure how light reflects when looking straight down at the diamond?

Better than that.

The ASET scope gives different colors to the light that enters the diamond from 3 ranges, the horizon, straight up and in between.

A well cut diamond will present a pleasing combination of all three.
It will also continue to do this as you rock it back and forth, although this cannot be captured in one picture.

The reason this is groovy is in real life the light from those three areas is usually different, so the ASET identifies diamonds that will provide pleasing contrast and scintillation in real life.

Kenny,

Off-topic, but important to mention.

The ASET basically shows potential brightness of the stone.

Depending on which ''school of fire'' one believes, that can also indicate or not indicate potential fire. Considering that there is scientific disagreement about how the assessment of the observation of fire should be done, I find it better to refrain from commenting on it.

The same is even more true with scintillation, the under-studied aspect of light performance. Yes, there is agreement that the contrast-pattern (ASET-blue plus leakage) contribute to scintillation, but the true operation of scintillation is still under-studied. The way that you describe this ASET-assessment is not correct. One cannot predict scintillation based upon ASET.

Live long,

 

[Paul-Antwerp]

Date: 3/25/2010 3:55:27 PM
Author: oldminer
The AGA Cut Class charts are good screening tools for fancy shapes. One must choose an outline which pleases them. This is very personal and not part of the function of screening by parameters. The charts will help you target stones which look reasonably large for their weight because better quality stones are not overly deep. The charts will help consumers avoid girdles which are overly thick or overly thin. Thin girdles can contribute to unforeseen durability issues and thick girdles contribute to excess weight and correspondingly less visual size. Shallow crown diamonds may have durability issues, especially near pointed ends in pear and marquise shapes. Steep crown diamonds are not so problematic. Tables within certain ranges of width allow for maximization of sparkle and fire around the crown. Overly large tables may hurt light performance and overly small tables will not look like the kind of diamonds dealers agree are premium, fine cuts. The length to width ratios are also non-grading suggestions based on dealer preferences. Consumers are free to choose any length to width ratio they personally prefer.

The charts take into account what experts know intuitively about diamonds, but what they have generally avoided in communicating to customers. The more blind diamonds are, the easier it is to sell the less than fine stones for premium prices. Diamonds and diamond dealers are tricky as all small merchants are. Try to buy oriental rugs at an Indian or Arabian bazaar and see how knowledge is the basis for making a good deal. The more you know, the better a deal you may make.

I think the criticism here is based on misunderstanding of what the AGA system does and what is does not do. People have said for a long time that they don''t do what they are supposed to do, yet consumers use them and find great make fancy shapes. If you go through the parameters for round diamonds, you''ll find the GIA and AGS0 stones are in the 1A-1B categories. I did this before GIA and AGS did it and I believe I did it right. The fancy shapes which make 2B and higher grades are all worthy of consideration. Cutters do not go out of their way to make 1A fancy cuts, but of those I''ve seen, they appear to be excellent looking. Cutters are very smart and do cut great looking diamonds when they are able to use such fine proportions. Why would they cut an ugly diamond with such excellent proportions? They wouldn''t.

The AGA system helps consumers eliminate diamonds which have obvious parametric problems. It helps those who want very fine stones to know where the sweet spots are in a gradual way. There are many great diamonds in fancy shapes which are 2B and better and with that in the consumer''s mind, I still believe the AGA system is very helpful to their search.

Those who disagree usually are those who are hoping to sell fancy shaped diamonds which have durability or visual size issues that a novice consumer would not understand unless they use the AGA system for screening. This sort of bias is understandable by anyone reading this, but just because eight or ten critics say the system is worthless, does not make it so. In fact, the noise making implies to me the uncomfortable elements of truth which some might prefer to just go away are clearly evident to consumers in the AGA system.

If Paul would cut AGA 1A ovals or pear shaped diamonds and market them he''d find that there are consumers who would love his production. It would take a lot of money and courage to buck the mainstream, but with enough staying power a cutter could carve a super niche with finely cut, beautiful diamonds which closely fit what I have deduced at top cut diamonds. No, I''m not the GIA, but this is the work of many years and based on observations of many diamonds. I have always asked for constructive advice and a few here have shared some with me. I have changed the charts a few times in order to do the job better. Saying they are worthless is just not helpful to anyone and in my opinion is not the best advice.

Thank you for your reply, David, it was enlightening, but totally off-topic, since a consumer cannot use the AGA-charts when considering the virtual list of diamonds, simply because most of the needed data are not available.

Then again, I did say that I do not agree with the charts, so I am a bit shocked by your highlighted remark. Reading your thread now, in which you explain that the charts are based upon a visual-size assessment (not correct in most shapes), durability issues (no comment) and a disputable theory about the table-size being linked directly to light performance, I am even more convinced about my disagreement with the charts.
Sorry for digressing even further.

Live long,

 

[Paul-Antwerp]

Date: 3/25/2010 4:13:38 PM
Author: mrskantz
Paul,

I recently bought an amazing princess cut that follows what you are saying. My jeweler also isn''t a huge fan of the IdealScope. It did see a Sarin machine and another jeweler who raved about it.

Here are the specs:
1.2 Princess Cut
Color: H
Clarity: VVS1
5.94 x 5.76 x 4.44
Depth: 77.1%
Table: 69%
Girdle: Medium to Slightly Thick
Cutlet: None
Polish: Very Good
Symmetry: Excellent
Fluorescence: None

Mrs Kantz,

With these data, I cannot say anything, positive nor negative, about this stone. I do not understand how this example could follow what I am saying.

Live long,

 

[Paul-Antwerp]

Date: 3/25/2010 4:35:15 PM
Author: kenny
QueenMum, frankly I bought our ACA, Solasfera, generic asscher and the Octavia (and three other rounds) without consulting the AGA chart.
I didn''t feel the need to myself.
I felt confident in the light performance of my choices before and after the sales.

I support its existence and use as a tool for shoppers of of the fancy cuts like pear, radiant marquise etc.
Is it perfect or does everyone agree on the data?
No, but it''s better than nothing.

Shopping for fancy cuts online is difficult.
I''m hoping Paul started this thread because he has some clever new tool up his sleeve.

Sorry to disappoint you, Kenny, that is not the reason for this thread.

The reason is to reflect upon realities that are often conveniently neglected. Once a problem is identified, it does not need a lot of geniuses to find various solutions. The first thing to do is to identify a problem, and not to neglect it.

Live long,

 

[Paul-Antwerp]

Date: 3/25/2010 7:17:28 PM
Author: Rockdiamond
Wink, my apologies. I did not consider the use of the word ''measure''- although how the ASET is commonly used here seems a lot like measurement to me.

My point is that ASET photos show a single perspective, light coming from a single direction.

I have no doubt whatsoever that your assessment of the stone on the left has merit- but if I was called upon to comment on it, I''d still want to see the stone.
Or a good series of digital photos- which would be far more illuminating than ASET IMO

Personally, I would never use ASET to either select, or reject a diamond.

The discussion about the merits of ASET is off-topic, since the stones on the virtual list do not come with an ASET.

And David, if you want to discuss this elsewhere, your highlighted sentence proves that you do not understand the tool. ASET shows you light from all potential directions, quite the opposite from your statement.

Live long,

 

[Paul-Antwerp]

Going back to the original topic, I see a lot of agreement with the fact that a consumer is facing an impossible task to select a few candidates from the virtual list.

At best, we must acknowledge that these initial choices are possibly coming to the forum, in order to get further advice from our regulars. So, if not on potential cut-quality, what is this initial selection based upon? Considering the options, I think that it will be entirely based upon carat weight, colour and clarity, AND most importantly price, compared to the other three factors. Basically, chances are great that a consumer starting his search on the virtual list will first consider the ones priced apparently cheapest, considering weight, colour and clarity.

I might be wrong, but I think that the probability of getting a great cut-quality when the first rejection is based upon price is relatively small.

As such, if our regulars take this first selection for granted, and try to choose the best in that selection, I fear that we are not doing the consumer a favour. Maybe, we should reflect upon reply-strategies.

Looking forward to your thoughts on that.

Live long,

 

[Karl_K]

Date: 3/26/2010 7:16:16 AM
Author: Paul-Antwerp
Going back to the original topic, I see a lot of agreement with the fact that a consumer is facing an impossible task to select a few candidates from the virtual list.
Live long,

Paul, well some consumers had better systems than others on figuring out which stones to call in, my track record with asschers was very good.
Part of the reason was being able to recognize a couple different cutters work by the numbers.
Your princess cuts could be picked out of a virtual list in the same way once they were discovered.
There were and are a couple cutters that have a much better chance of being excellent asschers than others on the list, there is two that was guaranteed not to be acceptable that could be sorted out the same way.
Sometimes I knew a stone was not going to be acceptable and it was frustrating when it was insisted on being called in because it was a couple hundred cheaper.
So you are right sorting by price is a bad move, but calling in the most expensive on the list can be just as bad.

That your vendor knows how to pick the right supplier/cutter is important when calling diamonds in.

 

[oldminer]

The AGA system is a craftsmanship screening tool and NOT a beauty or Light Return estimation tool. Beautiful stones often lie outside the top grades, but the top grades contain most of the finely crafted stones. Finely crafted diamonds have common components even in different shapes. Slightly thin to slightly thick girdles are best for durability and visual size. Tables from about 53% to 60% give what I believe to be a best potential outcome for crown height ranges of approximately 10% to 15%. Shallow pavilions lead rapidly to watery appearance with light leakage.

No doubt many fine looking fancy shapes have deeper total depth percentages than in the AGA charts and look excellent, but they generally look smaller than alternative choices which weigh the same and may look larger for the same money. The measurement of depth percentage only against the width in some fancy shapes makes the depth percentage a less than optimum measure, but the GIA in their traditional system did not take length into account and that now would be not only useful, but easily done in today''s automated world.

The charts are governed by rules which many people have never read or avoid understanding although the rules accompany the charts. The rules give increased lattitude to the final grade and help to make up for machine error in measurement and also to give fair grading in the overall since there are numerous combinations of parameters being considered. In the automated grader these rules are built in and the grades obtained often are different than grading the diamond based on the worst component.

The criticism is understood and many people will see that not everyone agrees, yet I see consumers, not dealers, being protected by better understanding of slight or more major problems when confronted by those who would gladly sell them anything without mentioning durability or visual size issues and only call their attention to ASET, I-S, or "beauty" features which promote the stone in a positive way. Sure, that''s salesmanship and naive consumers need protection which only a few great retailers and vendors care about. Fortunately many of the most caring vendors I have ever met are on Pricescope. This is a most unique and special environment which we all should treasure.

In the end, my problem is with dishonesty in disclosure, not with vendors or with beautiful diamonds. Beauty is primary with diamonds, but consumers should get durable stones and the best combination of visual size to weight which also gives great light return elements... Thanks to all for your participation and patience with this long post.

 

[caolsen]

As a complete civilian to the ''trade'' who also loves fancy cuts, this has been a great read. I have learned massive amounts on PS in genral but a great deal about the Cut Grade in particular on this one.

The expertise on this forum is amazing.

Thanks!

caoslen

 

[Karl_K]

Date: 3/26/2010 9:04:19 AM
Author: oldminer
No doubt many fine looking fancy shapes have deeper total depth percentages than in the AGA charts and look excellent, but they generally look smaller than alternative choices which weigh the same and may look larger for the same money.

The above statement is not true.
In step cuts depth is not proportional to spread.
It is also true in many fancies.