Evaluating Cut – time to add Light Performance to certifications

[Cehrabehra]

Date: 7/26/2007 1:41:19 PM
Author: DiamondDumbie


If you are evaluating diamonds that you are buying sight unseen (via the internet or a distant retail store), how do you determine the best diamond when you cannot see the diamond? Nobody is going to send you multiple (2 or 3) diamonds to see which one is more pleasing to the eye. Are they?

1. Find a vendor you TRUST.
2. Find a diamond or a few diamonds you''re interested in.
3. Ask here for advice on a specific diamond (optional)
4. Purchase a diamond with a return period for personal evaluation
5. Arrange for a couple diamonds to be sent to an approved appraiser for your viewing

 

[Cehrabehra]

Date: 7/26/2007 1:58:11 PM
Author: JohnQuixote

Date: 7/26/2007 1:41:19 PM
Author: DiamondDumbie


If you are evaluating diamonds that you are buying sight unseen (via the internet or a distant retail store), how do you determine the best diamond when you cannot see the diamond? Nobody is going to send you multiple (2 or 3) diamonds to see which one is more pleasing to the eye. Are they?

Ah, but what is ''best?'' We have ways to assure high performance. Beyond that it''s a matter of taste. Once you have identified several diamonds which are all top performers in their class & clategory there are still slight differences. It''s like the finalists in the Miss America pageant. They all have great pedigree, top appeal and wonderful character but the subtle nuances of which finalist suits your personal taste ''best'' is something only you can decide. PS enables conversation and brings a host of experienced people together to help those who would like to go as far as possible sight-unseen. Most people walking the earth just want something sparkly. For those wanting to put even the top finalists through a ''27 point personality questionnaire'' you have PS.

John, I really think this should be in your sigline LOL It sums it up... I can even think of drumming/music metaphors....

 

[strmrdr]

Date: 7/26/2007 2:41:27 PM
Author: Cehrabehra

Date: 7/26/2007 1:29:39 PM
Author: strmrdr
buying an EC/SE based in light return only is a huge mistake.
As a matter of fact a prominent PS vendor started carrying better asshers when they stopped using the b-scope on them.
The highest light return does not the most beautiful diamond make in any cut.
The best diamond is one that combines several elements in a pleasing to the eye combination.
With rounds it is possible to get near the max light return and keep other properties but even the best super-ideal diamond trades some raw light return for fire and contrast.

Further: do a search on contrast brilliance.
Brilliance without contrast is less bright.
http://www.acagemlab.com/articles/Describing.htm

I love that you think like this storm.... kudos!

The funny thing is that I didn't really get diamond performance until I started studying asschers and had to come up with answers on my own instead of having a whole ton of information already packaged up and ready too go(tutorials and stuff).

 

[Cehrabehra]

Date: 7/26/2007 3:31:12 PM
Author: strmrdr

Date: 7/26/2007 2:41:27 PM
Author: Cehrabehra

Date: 7/26/2007 1:29:39 PM
Author: strmrdr
buying an EC/SE based in light return only is a huge mistake.
As a matter of fact a prominent PS vendor started carrying better asshers when they stopped using the b-scope on them.
The highest light return does not the most beautiful diamond make in any cut.
The best diamond is one that combines several elements in a pleasing to the eye combination.
With rounds it is possible to get near the max light return and keep other properties but even the best super-ideal diamond trades some raw light return for fire and contrast.

Further: do a search on contrast brilliance.
Brilliance without contrast is less bright.
http://www.acagemlab.com/articles/Describing.htm

I love that you think like this storm.... kudos!

The funny thing is that I didn''t really get diamond performance until I started studying asschers and had to come up with answers on my own instead of having a whole ton of information already packaged up and ready too go(tutorials and stuff).

Well, I feel the same about antique style cushions as you do. I don''t think all of it is about light return - granted it can still be very good and excellent, but I''ve been wearing a 10mm round and while the RING looks lovely from the side, the stone is meh. It has a wonderful face up range but the light is designed to come in and go out the top. And I know it isn''t in the realm of superideal, but with my stone all of that "leaked" light makes for a very gorgeous stone from any angle. You can look at it in profile and the stone itself still radiates. When john said he could get performance but beyond that it is taste.... I think you and I understand that sometimes preference means you lower one type of performance in order to gain other types. I really relate more to what you say about asschers and emeralds than I do to rounds or ovals (which are also brilliant cut like my stone).

 

[Garry H (Cut Nut)]

Sergey sivovolenko was the first to note that there is no ability to compare diamonds of different cut with any cut rating systems.

We in the Cut Goup believe this is a big failing.

All the direct assesment and AGS type technologies could do that, and people ought to be mature enough to understand a marquise is not going to rate as high as a round. But they and their trade clients are afraid.

The worst of that is that it impedes the development of better and better fancies which have a huge way to go to catch up to the round brillinat.

Consider the RB 50 years ago - many modern fancies like Princess and asschers would outperform most 50 year old round brilliants. if the starting line and the finish were the same for all cuts - we would all benefit.

So I like your smart thread Diamond Dumbie

 

[stebbo]

I see no reason to evaluate cut any further than it is, even if it was possible to rate a highly subjective factor. In fact, I think AGS has even gone too far. Why make it simple for EVERYONE to find a stunner? There is already enough information available. There are ample specs, tools, appraisers and highly reputable dealers to make buying even sight-unseen 100% successful.

Everyone here who puts some effort into research ends up with a nice diamond at a good price. That''s the reward. The excitement of researching and learning about something new and meeting a new community is also reward.

If someone doesn''t put in the research, then they won''t even know what they might be missing anyway, so all is fair. I''m sure you have many diamond-illiterate friends who are incredibly happy with their (what would probably be an) AGS-6. Who cares if they overpaid, they''re happy. An absolute ''quality indicator'' would only put pressure on them to think they have to spend more. And did they truly overpay anyway? How much is the time spent researching worth?

It''s only when one learns there is better that it must be had, and if you learn there''s better, you''re already on the path to finding it. All''s good.

 

[Garry H (Cut Nut)]

Date: 7/27/2007 12:58:18 AM
Author: stebbo
I see no reason to evaluate cut any further than it is, even if it was possible to rate a highly subjective factor. In fact, I think AGS has even gone too far. Why make it simple for EVERYONE to find a stunner? There is already enough information available. There are ample specs, tools, appraisers and highly reputable dealers to make buying even sight-unseen 100% successful.

Everyone here who puts some effort into research ends up with a nice diamond at a good price. That''s the reward. The excitement of researching and learning about something new and meeting a new community is also reward.

If someone doesn''t put in the research, then they won''t even know what they might be missing anyway, so all is fair. I''m sure you have many diamond-illiterate friends who are incredibly happy with their (what would probably be an) AGS-6. Who cares if they overpaid, they''re happy. An absolute ''quality indicator'' would only put pressure on them to think they have to spend more. And did they truly overpay anyway? How much is the time spent researching worth?

It''s only when one learns there is better that it must be had, and if you learn there''s better, you''re already on the path to finding it. All''s good.

Selfish but true Stebbo.

With color the difference between an off color (M) and top color (D) is about 3 times for 1ct sizes.
With Clarity it is 5 to 10 times the difference IF to I3

The difference between a woofer make and a stone you would buy is about 2 times.

Once we can all agree on a cut grading scale i expect the difference might be about 4 to 5 times.

That means all the off makes now could be worth more recut to real beauties

 

[diagem]

Date: 7/26/2007 8:24:07 PM
Author: Garry H (Cut Nut)
Sergey sivovolenko was the first to note that there is no ability to compare diamonds of different cut with any cut rating systems.

We in the Cut Goup believe this is a big failing.

All the direct assesment and AGS type technologies could do that, and people ought to be mature enough to understand a marquise is not going to rate as high as a round. But they and their trade clients are afraid.
And people shouldnt expect a MQ to have the same appearance as a Round..., do you really think that''s the problem??

The worst of that is that it impedes the development of better and better fancies which have a huge way to go to catch up to the round brillinat.

I agree on this one..., allthough fancy shapes have their own rules..., and in my opinion cant be compared to rounds...
I assume this is the main problem you "cut group" are tackled by.
I also must admit..., due to the rapid changes our industry is going through, I am witnessing a natural path to better fancy cuts thanks to "trial & Error" combining with the technology available these days.

Consider the RB 50 years ago - many modern fancies like Princess and asschers would outperform most 50 year old round brilliants. if the starting line and the finish were the same for all cuts - we would all benefit.
Yes..., but look at the market reality..., Diamonds that were cut 50..., even 300+ years ago are considered beautiful sought after Diamonds even in todays high tech Diamond cutting age.

A "rated" Diamond also means a symmerical uniformed type Diamond look..., and there are plenty of people that dont care for it and/or dont like this type of look.

What I am trying to get to is..., that the fact that a Princess Cut Diamond will out-perform an older cut Diamond does by no means make it more attractive/beautiful.

So I like your smart thread Diamond Dumbie, me too!!!

One thing is for sure..., light performance will help commoditize the "Common" Diamonds out there..., and you are 110 % correct DiamondDumbie...
Its can serve as a great tool for sight-unseen marketing!

 

[Regular Guy]

Date: 7/27/2007 4:08:58 AM
Author: Garry H (Cut Nut)

With color the difference between an off color (M) and top color (D) is about 3 times for 1ct sizes.
With Clarity it is 5 to 10 times the difference IF to I3

The difference between a woofer make and a stone you would buy is about 2 times.

Once we can all agree on a cut grading scale i expect the difference might be about 4 to 5 times.

That means all the off makes now could be worth more recut to real beauties

I think this general point above is an important one.

But...where I''ve highlighted it...shouldn''t that be both agree and understood?

I mean...although there is a difference between AGS & GIA standards...the difference isn''t exactly remarkable.

Also, note...when you go into virtually all stores selling diamonds, two things may be true:

a) they will very possibly explain the concept of ideal lighting to a diamond, and encourage a good buy on that basis
b) they will then explain the 4 Cs, describing C as essentially the shape of the diamond, and completely forgetting what they had just told them, not incorporating it whatsoever.

Isn''t this true, still. Despite...GIA certs now coming out with cut standards on them?

I posted about this 3 years ago (at point #3) when I thought I was about to leave this board.

So...I''m not sure that it''s the current discrepancies in the nits between the systems that causes the delay in the valuing of the nature of the cut. It''s something else.

Certainly, time & Pricescope would add to the understanding. But...what else?

 

[diagem]

Date: 7/26/2007 2:22:52 PM
Author: strmrdr

Date: 7/26/2007 2:06:57 PM
Author: DiamondDumbie




Is it really that difficult? Honestly, I do not know. It is just hard to imagine this cannot be done within an industry with so much history, experience and intelligence.

Strmrdr, i am impressed at your view....

Actually that is one of the biggest things holding cut grading back.
The tradition of trust me in the industry. Its not holding it back but finaly it is shifting to include the consumers who are willing to invest their time learning.
Strmrdr, this industry can''t survive without that "tradition of trust" you are talking about.
Sadly that trust has often not extended to consumers which has led to grading reports and the huge labs dominating the consumer end of the market.
Too understand the diamond market you have to understand the history.
True, laboratories are controling a specific bolt in this huge world called Diamond/Diamond jewelry marketing..., and this bolt is a significant one.
It has been a very controlled market and the controlling parties control is slipping more and more every day.
This is leaving people in a scramble to compete and put food on the table.
I dont know which was better for the consumer..., a controled market meant steady prices for a long term..., today we are witnessing severe movements in specific segments..., the consumer is not feeling it yet..., but (in my opinion) it is irreversible,and only a matter of time until it will reach the consumers.
It happened in other industries starting in the 70s but because of the tight control of the industry it lasted longer in the diamond industry.
Now it is going threw a very painful realignment. So true...
One local shop closed its door last month, the owner retired and his son found it easier to make money selling used cars than diamonds and wanted nothing too do with the trade.

Thats because this industry is going through a major change..., not only the "controlling parties" are loosing control...., but this industry is moving towards professionalism..., groups like the "cut group" et al are researching and at the same time educating..., it''s a must for moving forward...
Unfortunately (but cant be avoided or stopped), shops and businesses run by unprofessionaly qualified staff are at "High" risk of droping out of the game.

This industry is not as simple and easy ias it may seem!!!

 

[strmrdr]

not going to do a huge quote but interesting post DiaGem.

Sure the industry could thrive on a cash based market, it would drive a lot of marginal stores out of business however.

Until prices rise and fall like a normal market the industry will remain in the dark ages.
The best thing that could happen is a rise of a professional cash based non-controlled supply chain on the ashes of the current system.
Its going too happen and is happening.
Clan based supply chains do not last in today''s market place they get chewed up and spit out by WalMart.

 

[DiamondDumbie]

Date: 7/26/2007 8:24:07 PM
Author: Garry H (Cut Nut)
Sergey sivovolenko was the first to note that there is no ability to compare diamonds of different cut with any cut rating systems.

We in the Cut Goup believe this is a big failing.

All the direct assesment and AGS type technologies could do that, and people ought to be mature enough to understand a marquise is not going to rate as high as a round. But they and their trade clients are afraid.

The worst of that is that it impedes the development of better and better fancies which have a huge way to go to catch up to the round brillinat.

Consider the RB 50 years ago - many modern fancies like Princess and asschers would outperform most 50 year old round brilliants. if the starting line and the finish were the same for all cuts - we would all benefit.

So I like your smart thread Diamond Dumbie

I had a strong feeling you would agree!!

Light Performance grade would be valuable when comparing two like diamonds (shape – ie Emerald, Carat, Color and Clarity, these areas are nearly identical).

This is no different than how Color is valuable when comparing two like diamonds (shape – ie Emerald, Carat, Color and Cut, these areas are nearly identical).

Polish and Symmetry is not enough to grade Cut. This cannot be argued. It is undisputable that the brilliance, fire and sparkle are the best means to evaluate Cut. Therefore, make this part of the diamond report.

How is this accomplished?

Use a BrillanceScope and IdealScope. GIA or AGS can create a setup for every diamond that is repeatable. It is not difficult. Furthermore, this is a good start and it can enhance with time. This solution is definitely better than doing nothing at all.

 

[DiamondDumbie]

Date: 7/26/2007 3:27:42 PM
Author: aljdewey
Well, let me issue a challenge.

Since this is such a ''simple thing'' to fix in your eyes, why don''t you feel free to add to this thread your suggestions on precisely how this should be done.

Before you do that, please know that there are many learned minds in the field who contribute to these forums---MIT graduates, people with 30-40 years in the business, major players at grading labs, etc. I''m sure they''ll read your suggestions with great interest.

Unless you relish completely embarassing yourself, I''d suggest taking a quick read-through on some of their threads first to get a feel for what paths have already been covered. Then, when you are ready to unveil your suggested solution that everyone else has missed, I''m sure they''ll all be waiting to hear it.

Try reading my posts within this thread and you will see my recommendations. If everyone was afraid or embarrassed to stick their neck out and make recommendations for improvement that may be considered out-side-the-box, our civilization would be decades or centuries behind where we are today.

Does it look like I am worried about being embarrassed? Honestly? Am I not putting my newbie butt out for everyone to see?

It is not as if I am going into this subject without any prior research or knowledge. However, I also realize that there are a plethora of smarter people within the diamond industry. That is why I put this subject on the table. It merits the attention of those capable of making the necessary improvements.

I would also presume you are cable of more constructive and productive input than your latest thread. I am going on another limb, but I suspect you are better than that.

 

[DiamondDumbie]

Date: 7/26/2007 3:19:26 PM
Author: decodelighted

Date: 7/26/2007 2:59:07 PM
Author: DiamondDumbie

Date: 7/26/2007 2:05:28 PM
Author: decodelighted
Ultimately the reponsibility for seeking out more info falls on the people doing the BUYING -- not the people doing the selling, or even the ones doing the analysing. I guess you''re wishing there was a kind of not-for-profit diamond evaluation panel. Or even a paid one. But, as many people have said, it''s just impossible. Because the factors involved are AESTHETIC ... INDIVIDUAL TASTES ... a soup of too many flavors & potentially awesome/horrific combos to accurately 100% of the time predict what''s ''best''.

Am I missing something? GIA and AGS are not the Sellers.
I DIDN''T SAY THEY WERE THE SELLERS ... I SAID ''OR EVEN THE ONES DOING THE ANALYZING'' THE GIA & AGS ARE ''ANAYLZERS'' BUT NOT ''JUDGES'' AS I DO BELIEVE ''JUDGING'' IS IMPOSSIBLE.

You say it is “just impossible”. Wow! That is a telling statement. It is pretty clear why you have taken the position you have taken. First of all, nothing is impossible. Without question, quantifying the Cut criteria is FAR from impossible especially since it is already being done.
WAIT A DAY, A MONTH, A YEAR ... TASTES CHANGE. NOT LONG AGO PEOPLE THOUGHT 60/60 DIAMONDS WERE ''SUPER IDEAL'' -- PERFECTION IS A MOVING TARGET, THERFORE UNKNOWABLE.

Is Jessica Alba more beautiful than Kate Hudson? You can map out the geometry of their faces and analyze the symmetry but - c''mon ... WHY WOULD YOU? Or wait, is it because they have no intrinsic value? They''re not on ''the market'' -- well, yes they are. Who makes a larger salary per movie? Who commands more for endorsements? That value is based on more than LUMINESCENSE I''d bet.

You just do not understand the point of Light Performance.

Light Performance is used to evaluate between two similar cut diamonds. Just as Color is used to evaluate to like stones, as I mentioned above. For example, two Emerald cut diamonds with identical – Carat, Color and Clarity.

Your analogy of two different women is like comparing a Round cut versus an Emerald cut.

The correct analogy is how to evaluate the difference between two identical girl twins. An IQ test could tell you which girl is smarter.

This analogy points out how Light Performance can be used to evaluate the difference between two very similar diamonds that have different light performances. I understand no two diamonds are identical. However, like human identical twins, the difference can be almost unnoticeable but no two humans are completely identical just as no two diamonds are completely identical.

Now do you see how Light Performance can be utilized within a diamond report, such as GIA or AGS?

 

[diagem]

Date: 7/27/2007 1:39:26 PM
Author: DiamondDumbie

Date: 7/26/2007 8:24:07 PM
Author: Garry H (Cut Nut)
Sergey sivovolenko was the first to note that there is no ability to compare diamonds of different cut with any cut rating systems.

We in the Cut Goup believe this is a big failing.

All the direct assesment and AGS type technologies could do that, and people ought to be mature enough to understand a marquise is not going to rate as high as a round. But they and their trade clients are afraid.

The worst of that is that it impedes the development of better and better fancies which have a huge way to go to catch up to the round brillinat.

Consider the RB 50 years ago - many modern fancies like Princess and asschers would outperform most 50 year old round brilliants. if the starting line and the finish were the same for all cuts - we would all benefit.

So I like your smart thread Diamond Dumbie

I had a strong feeling you would agree!!

Light Performance grade would be valuable when comparing two like diamonds (shape – ie Emerald, Carat, Color and Clarity, these areas are nearly identical).

This is no different than how Color is valuable when comparing two like diamonds (shape – ie Emerald, Carat, Color and Cut, these areas are nearly identical).

Polish and Symmetry is not enough to grade Cut. This cannot be argued. It is undisputable that the brilliance, fire and sparkle are the best means to evaluate Cut. Therefore, make this part of the diamond report.

Not necessarily..., there are novelty cuts out there that can''t be and are not evaluated on the same parameters. You need to take those into consideration!!

How is this accomplished? I assure you it is NOT that simple to accomplish!!

Use a BrillanceScope and IdealScope. GIA or AGS can create a setup for every diamond that is repeatable. It is not difficult. Furthermore, this is a good start and it can enhance with time. This solution is definitely better than doing nothing at all.

 

[CaptAubrey]

Date: 7/27/2007 1:56:54 PM
Author: DiamondDumbie

The correct analogy is how to evaluate the difference between two identical girl twins. An IQ test could tell you which girl is smarter.

This analogy points out how Light Performance can be used to evaluate the difference between two very similar diamonds that have different light performances. I understand no two diamonds are identical. However, like human identical twins, the difference can be almost unnoticeable but no two humans are completely identical just as no two diamonds are completely identical.

Now do you see how Light Performance can be utilized within a diamond report, such as GIA or AGS?

The problem here, and the one you seem unable to grasp, is that there are established and agreed-upon methodologies for conducting IQ tests. Not so with diamond light performance. There are at least half a dozen approaches currently being used in the market that I''m aware of, and it''s not just because certain parties are trying to establish their own proprietary methods as the standard (though that''s part of it). It''s because the experts don''t agree on how to do it.

So. Yes, let''s test light performance. What method do you propose using, and what''s your justification for choosing that methodology?

 

[denverappraiser]

Date: 7/27/2007 1:39:26 PM
Author: DiamondDumbie

It is undisputable that the brilliance, fire and sparkle are the best means to evaluate Cut.

I dispute this.

Many others here have disputed it. Beauty is the best means to evaluate cut. I agree that beauty is a difficult thing to measure but wishing that it were the same as light return because that's easier to quantify and to measure does not make it so.

Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Jewelry Appraisals in Denver

 

[strmrdr]

Date: 7/27/2007 3:26:50 PM
Author: denverappraiser

Date: 7/27/2007 1:39:26 PM
Author: DiamondDumbie

It is undisputable that the brilliance, fire and sparkle are the best means to evaluate Cut.

I dispute this.

Many others here have disputed it. Beauty is the best means to evaluate cut. I agree that beauty is a difficult thing to measure but wishing that it were the same as light return because that''s easier to quantify and to measure does not make it so.

Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Jewelry Appraisals in Denver

Well said...
first: sparkle <--- how is this defined? number? area? intensity?
Its impossible to define a fair metric so forgetting it...

Lets define 100 as the the most possible.

Lets take 2 rounds...
one scores:
brilliance - 85
fire - 100

The other scores:
brilliance - 100
fire - 85

They can both be equally beautiful to me.
btw that would equal a oec and a super-ideal RB try and say both arent beautiful and Cehra is gonna kick ya butt :}

 

[stebbo]

Date: 7/27/2007 4:08:58 AM
Author: Garry H (Cut Nut)
Selfish but true Stebbo.

With color the difference between an off color (M) and top color (D) is about 3 times for 1ct sizes.

With Clarity it is 5 to 10 times the difference IF to I3


The difference between a woofer make and a stone you would buy is about 2 times.

Once we can all agree on a cut grading scale i expect the difference might be about 4 to 5 times.

Exactly - and you can bet the top cuts will shift up in price more than woofers will move down.

So everyone who is looking for the definitive cut grade, be prepared to pay for it. Premium in any commodity, whether it be saucepans or cars, doesn't come at only twice the price of the 'common' make, but 5 to 10 times. We've got it good with diamonds, shhhh...

That means all the off makes now could be worth more recut to real beauties

Totally believable, just as it can currently be cost effective sacrifice a bit of weight for better proportions and/or clarity, make premium cuts worth too much more and we'll start seeing 5 caraters chopped into lots of little 'perfect' 50 pointers. I'd hate to be the cutter on that job.