GIA color grading

[kevinraja]

When a GIA report says a stone to be G color and med flourescence, does that mean that the GIA graded the stone to be G color discounting the med flourescence or they actually might have graded an H or an I color stone to be G color because of the medium flourescence?

 

[windowshopper]

kevinraja

i asked this of a few people and they said they can filter the fluor to accurately assess the color

 

[kevinraja]

Do you know how they do it?

 

[cflutist]

If I am not mistaken, color grading should be done against a dull white brackground (e.g. using a diamond trough) in a darkened room using filtered, cool white, balanced fluorescent light which is nearly free of ultraviolet. The GIA GEM DiamondLite provides such light.

Fluorescence is detected with any standard longwave ultraviolet lamp (aka blacklight). Sunlight also contains ultraviolet light but not as much as the former. The GIA GEM DiamondLite also has an longwave ultraviolet lamp built in. Best way for a consumer to check fluorescence is to go to a poster shop to look at your diamonds ... I''ve done that.

 

[windowshopper]

Date: 1/15/2005 8:39:32 PM
Author: kevinraja
Do you know how they do it?

no i dont

 

[valeria101]

If you have an afternoon .... there is allot of detail about what lighting GIA uses or used by Martin Haske on the site of Adamas Lab (link). He has been posting on Pricescope too. ''Guess the summary of Adamas records is that GIA gradually decided to give up filtering UW out of the standard grading environment, for better or worse. Actually, once you read their tytle, there is no turning back from the following spectrophotometry diagrams. The intro reads:

"35% Of Diamonds Graded Will Now Potentially Get A Better Color Grade By Fiat Of The Gemological Institute Of America"

According to a short article in Professional jeweler (199, each lab decided on either side at some point. (link) Here''s what they say:

"The Gem Quality Institute and the AGS Lab filter out UV rays when color grading diamonds. GIA doesn''t. Is there one right way?
[...]
#1. Gem Quality Institute now issues two grades for strongly fluorescent diamonds: one reflecting use of a filter, one without.
#2. The AGS Lab uses a permanent filter to screen UV light when color-grading diamonds.
#3. Martin Haske, owner of Adamas Gemological Laboratory in Brookline, MA, agrees.
#4. Diamond market expert Martin Rapaport [...] says the issue deserves further study, but that "GIA is still the standard..."

Take your pick, I guess

 

[windowshopper]

thats awful.......................so all GIA stones should have an independant appraisal to verify color I guess

 

[RockDoc]

The way to filter out UV is by using a piece of Lexan. I do here, plus use the Gran colorimeter, which is not eyes, but a machine. So with a fluorescent stone, it does give it a little "credit" since in most cases blue masks yellow.

Lexan is sold by plastic sheet dealers. It''s not too expensive a thing to have. Consumers can get one, inexpensively, but it is sort of academic to be color grading diamonds if you don''t have..

Diamond grading Master Stones

Grader''s eyes check for color/hue discrimination.

I have a diamond light, but don''t like the newer bulbs Gem Instruments sells. The new bulbs have a very light greenish tint to them. So I got another one. It is 5800 Kelvin and uses LED whites "bulbs" in it... It has about 150 - 200 LEDS in it... Pricey but gotta have it.


Another practice GIA & AGS is generally not to split grade a stone. Instead they average color. I have seen two stones with GIA reports that have been split graded but both were very low colors. One report said S-T .


Rockdoc

 

[kevinraja]

So G clor with med flour might actually be a H or a I color?

 

[windowshopper]

it would seem that is a possibility

 

[Brian Knox]

Bottom line is that color and clarity are opinions, there is an amount of subjectivity involved.

GIA, is one of the two highly respected labs in the industry for their grading standards, AGS being the other.

Therefore, a diamond from either of these Labs is much more likely to be what they say it is than second,third and forth tier Labs.

Still, it is impossible to speak in absolutes.

As well, color is a range, there are high G''s and low G''s

Go to a jeweler that can show you various GIA and AGS stones.

I feel the two top labs are equally strict on color.

 

[kevinraja]

We all know any opinion is subjective. The question here is a YES or NO question.

Is it possible that a GIA report''s G color with med flour might actually be a H, or maybe even a I color?

If yes, then consumers on PS should be alerted that when they buy a G med flour, they are actually buying a H or a I color and any combination of color & flour thereof. That will make sense why a G color No flour is pricier than a G color with med flour, as a G color with med flour is not a G, but it is a H or even a I color.

This is a very important issue, experts here better clarify this. Since most of the appraisers here are GIA certified, I hope to see a response from them.

If what I think is true, then GIA report is misleading. It should then state a G color with med flour as "G color as a result of med flour" instead of just mentioning G color & med flour.

 

[valeria101]

Date: 1/16/2005 8:19:10 AM
Author: kevinraja
So G clor with med flour might actually be a H or a I color?

Well... there are three things that keep me from saying that straight. It is quite clear and certain what fluorescence does, but how effective it is at making a difference seems to be orders of magnitude harder to pin down

Not that I am right... just saying what I happen to know.

How does this sound to you ?


#1. the degree of fluorescence is not graded nearly as tightly as color is, so it is not possible to say what amount of color shift there is until someone makes grades of fluorescence calibrated to fit degrees of color shift

Garry had a line up photo showing this.

#2. arguably, body color is always there but the tint caused by fluorescence is not. So how do you call a J color that looks like I 30% of the time ?

Now, I think #2 is a case of schizophrenia: the grading environment is designed to unrealistically tough on color (all white, while diamonds are not worn on white gloves) but fluorescence does not get the same treatment - the lighting used is not unrealistically tough on fluorescence since it does contain UV like most other sources do. Well, schizophrenia might not be the best word - inconsistent methodology is more likely, IMO.

If you guys want those diamonds regraded, than Martin Haske got his point across, it seems

 

[windowshopper]

yes ---how about a class action lawsuit by all purchasers of GIA certified stones with fluorescence from the date GIA stopped using the filter to assess color independant of fluorescence?


So is my D color with fluorescence really an E or and F? for the premium ones pays for D i sure hope so but I wouldnt bet on it

 

[kevinraja]

Class action lawsuit sounds like a good idea windowshopper

 

[valeria101]

Gia cares to demonstrate that the issue is not there - that the visual impact of fluorescence is neglijable... They have a study published to support this ( basically a pannel of professionals and buyers). The chart below was part of it.
Diamond colors are not very relevant in photo, but it does show that the degree on fluorescence varies quite a bit under each "name", I think.

Can''t believe anyone missed the opportunity of class acction, but fluorescence is discounted for higher color grades for reasonable doubt, as is. Leonid had some statistical evidence of the practice. It might be hard to tell what was discount on fluorescence and what was premium on cut on a diamond like yours WS (or those H&A rounds)... which is unfortunate lack of clarity, obviously.

Hope anyone can clarify how these price shifts can be understood and handled !

 

[windowshopper]

okay off topic but i have a great idea for a novel:

rabble rouser from Pricescope goes after GIA and diamond industry--they put out a hit on him.................. Kevin which movie star should play you?

 

[kevinraja]

Billy Bob Thornton who I think will portray well my "anti-establishment" and "rebel" attitude.

"Question the Authority. Don''t Ask Why. Just do it"

 

[valeria101]

No joke... prices make little sense. For example: take the current quotes for 3 carat D-F Ec (peers of your stone, WS...), there seems to be a consistent discount for medium fluorescence (there are no examples with strong), but from D to F prices overlap allot. It doesn seem that there is a consistent premium for D over F after all.

(PS: these three posts should ahve been one after another - couldn't follow the jokes while making charts!

and now they sound out of place

)

 

[windowshopper]

billy bob in slingblade or bad santa? (great in both.) in all seriousness this is troubling..............................in a big picture sense

 

[perry]

My understanding of the issue, is that potentially up to 10% of the diamonds GIA grades could be color shifted by one color, and a fraction of 1% might be shifted by 2 grades (light fluorescence will not shift a color grade that much).

Keep in mind that most diamonds of 1 carat or larger are sent to several labs for grading - and then the wholesaler sells the diamond with the best grade. Since GIA allows the UV to color shift - guess which lab's report gets presented more often with fluorescence diamonds...

More interesting is that several of the high quality pricescope vendors have reported in previous postings that GIA may not report fluorescense in diamonds that clearly have fluorescense.

The federal standards in regards to blue white diamonds - which are colorless diamonds with strong blue fluoresence require the use of "North Daylight" to grade these diamonds, and there is an old GIA definition of North Daylight from the period of the adoption of the federal standards that would indicate that diamonds should be graded without UV (Overcast sky would have minimal if any UV), and this also controls what kind of light spectrum is used (another shift by GIA).

Based on this I believe that you can easily argue that fluoresence diamonds are required to be color graded without UV. In fact, I have a hard time seeing how you could argue that you are not required - within the US - to use UV free light to color grade such diamonds.

I personally believe that a class action lawsuit is a good idea - and probalby winable: However, who is going to fund it. $100,000 for openers. Probably 1/3 to 1/2 million to take the case to completion, and if things take a strange turn - 1 million or more.

It is my understanding that Marty is trying to drum up the necessary support for such a lawsuit. The problem of course is that only the consumers are hurt by this. The wholesalers, and even the dealers make out because they are selling the diamonds as more valuable diamonds - based of course on the "industry expert".

My initial review of price reductions for fluoresence was that it was less than the price difference of a color shift one grade.

Unfortunately, the federal consumer protection department is largly ineffective as they have never really been funded well enough to persue many consumer frauds out there. That is one reason that State DA's seem to be more effective on many consumer protection issues - and you hear that a series of states have filed against some company for fraud more often than you hear about the federal governemnt filing against that kind of company.

This is not the first time that larger companies have strayed away from following the standards for reasons that always seems to help thier bottom line.

I will also note that the GIA cert provides the least amount of data as well (nothing related to cut dimensions or angles at all).

Perry

 

[kevinraja]

Interesting numbers Ana.

Since F color with mb flour is expensive than F color with no flour, I believe that F color with mb is actually F color discounting mb, which would make F color with mb look like a E or an F color, and that would justify the higher price for F color with mb compared to F with no flour.

 

[valeria101]

Date: 1/16/2005 10:19:33 AM
Author: kevinraja
Interesting numbers Ana.

Since F color with mb flour is expensive than F color with no flour, I believe that F color with mb is actually F color discounting mb, which would make F color with mb look like a E or an F color, and that would justify the higher price for F color with mb compared to F with no flour.

Oh... it''s never guaranteed that the fluorescent are rock bottom in each category - but they are always towards the bottom of the list. There''s not knowing if there is any other reason for the cheaper Fs to be that way. ''Guess one would need to call in those diamonds or at leats look at the rest of the info that I cut off.

Something else seems to stand out: once there is mb, there is no price difference between D and F , right ? Speaking of some average not down to the last cent, as usual.

Just as a half joke, ''cause I would not take numbers this lightly on a more serious note, but after looking at those quotes my question would be:

Can you guys tell D from F when there is some fluorescence around ?

Really ?

 

[windowshopper]

Date: 1/16/2005 10:26:13 AM
Author: valeria101

Date: 1/16/2005 10:19:33 AM
Author: kevinraja
Interesting numbers Ana.

Since F color with mb flour is expensive than F color with no flour, I believe that F color with mb is actually F color discounting mb, which would make F color with mb look like a E or an F color, and that would justify the higher price for F color with mb compared to F with no flour.

Oh... it''s never guaranteed that the fluorescent are rock bottom in each category - but they are always towards the bottom of the list. There''s not knowing if there is any other reason for the cheaper Fs to be that way. ''Guess one would need to call in those diamonds or at leats look at the rest of the info that I cut off.

Something else seems to stand out: once there is mb, there is no price difference between D and F , right ? Speaking of some average not down to the last cent, as usual.

Just as a half joke, ''cause I would not take numbers this lightly on a more serious note, but after looking at those quotes my question would be:

Can you guys tell D from F when there is some fluorescence around ?

Really ?

ANA--WHAT SCARES ME IS THAT MY STONE IS A D--WITH GIA NOTED FAINT FLOUR. THE APPRAISER SAID THE FLOUR WAS MORE LIKE MODERATE BLUE BUT I DIDNT CARE THINKING AS LONG AS IT S CRYSTAL CLEAR WHO CARES.........? SO DO HAVE A F COLOR DIAMOND?

 

[windowshopper]

Date: 1/16/2005 9:35:19 AM
Author: kevinraja
Class action lawsuit sounds like a good idea windowshopper

I KNOW SCADS OF LAWYERS.......................

 

[valeria101]

Date: 1/16/2005 10:33:3 AM
Author: windowshopper

Date: 1/16/2005 10:26:13 AM
Author: valeria101

Can you guys tell D from F when there is some fluorescence around ?

ANA--WHAT SCARES ME IS THAT MY STONE IS A D--WITH GIA NOTED FAINT FLOUR.
THE APPRAISER SAID THE FLOUR WAS MORE LIKE MODERATE BLUE BUT I DIDNT CARE THINKING AS LONG AS IT S CRYSTAL CLEAR WHO CARES.........?
SO DO I HAVE A F COLOR DIAMOND?

That's why I asked about grading...

Only you know if the fluorescence detail about your diamond also came at the right price. Perhaps the appraiser who came up with the comment could clarify. There is not much left to say without dimamond in hand, as far as I know these things (not too far).

 

[RockDoc]

Date: 1/16/2005 9:35:19 AM
Author: kevinraja
Class action lawsuit sounds like a good idea windowshopper

Class Action Lawsuit......

Actually it isn''t such a good idea.

Firstly, a class action suit has to be "certified". Certification of a class action can take quite a while. Certification is not granted because it''s a more efficient way of bringing a lot of people together in order to save individual legal costs, it is granted because the court feels that it is better for the court to try a lot of cases together to save time.

Secondly, the members of the class action have to be damaged equally. This is tough to do, in this scenario. You''d have to file a separate class action for people who purchased D colors and got E... and D''s that got F''s etc.

Thirdly, let''s consider the results of other class action suits. Years ago there was a suit filed because computer monitor sizes were being misrepresented. The industry would say you''re getting a 15" monitor when the consumer actually got less size than that. The outcome.. was that if a consumer bought a monitor in the future, they would get a small credit towards the next purchase. Those who didn''t buy another monitor got nothing.

Then there''s the GTE conversion to Verizon, where the stockholders were cheated on the transfer of stock. The attorneys got millions in fees, and the members of the class got I think 25 cents per share.

Then the battery class actions, for proper disposal of the batteries. The gov''t got money from fines, but the consumer got nothing but increased costs for batteries.

The other problem with with suing over the misgrading of color, is that in many suits, like this, GIA didn''t prepare the report for you directly. The seller did. So probably each person ( unless the Court decided differently after a motion was filed) would have to file against their seller, and the seller would have to sue GIA. See State of Florida case against Neiman Marcus)

Then there''s the situation of appeal and collection of the monies awarded in both civil suits and class actions. If companies lose, many times they claim bankruptcy and keep the class plaintiffs in limbo for years.

Also consider that as an individual in a class action, that you may lose control of the outcome.. Your only option is to leave the class and sue individually if you don''t agree with the settlement if one is negotiated.

Just try to report the facts of the system since most consumers have the false belief that a class action benefits them when many times it doesn''t. There are benefits in a class, but a lot of thought and planning have to go into it.

Another issue, is a law firm has to be willing to finance such an action. Legal fees for class actions are expensive. Since the plaintiffs do not advance the legal costs, someone has to. This burden is placed on the law firm. Lawfirms are not going to invest in a class action unless there''s a "pot of gold" for them at the end of the rainbow.

Perhaps this is not the best of sources, but two movies, sort of capture the nature of this situation.... one was the legal movie (starring John Travolta) that was a representation of the bad water case in Wooburn MA, ( Marty Haske''s neighborhood. The second one was Rainmaker with Danny De Vito and Matt ( his last name escapes me at the moment) where they win a case against the insurance company, and win a judgement with immense punitive damages, where the company claimed bankruptcy and the plaintiff got zilch.

Perhaps there are better way to get justice instead of "justus" , but that would take some serious research into how to plan it properly.

Rockdoc

 

[oldminer]

The grading of diamonds is still somewhat subjective. Less subjectivity in color grading is just around the corner, but determining how much UV content is to be allowed in grading color is not written in stone. It is not one of the Ten Commandments or part of any lesser legal code, but left up to labs and diamond people to decide how to market and grade their products. Caveat Emptor is good advice when such is the case.

One must understand that larger diamonds look darker than identical color graded, smaller diamonds. No other product on earth is color graded or matched in this way. If a color in a thin piece of glass didin't match the color of a thick piece of glass, no one would would claim they match, but with diamonds, this is the way it is done. Color grading is on a sliding scale that matches the degradation of color to the voulme or weight of the material to adjust for absorption. Now, it makes some sense. Take a large, say 5ct, H color diamond, should a tiny piece be chipped off it would match an H color 0.25ct stone, yet as a 5ct stone the H would look quite a bit darker than a H 1/4ct diamond. It is the finances being considered. Matching of color grades is very much a secondary thing. Just think how much less that large diamond would be if it was graded as if it was glass! If it was graded a I or J color there would be gigantic consequences in the value or price because of the way these things are marketed.

Because of the very unqiue character and high value of diamonds, color grading is, up to now, an art, not a science. The decision of how much UV to allow in color grading is up to the experts and the marketers. You can see the market is very smart in that value/price is adjusted for diamonds where fluorescence creates a problem or a potential objection. I wear a very fluorescent diamond every day, which I like, so it is not a problem when you know what you are buying.

When a power comes into the market with the rights to tell everyone else how to grade diamonds, we will have more consistent grading. What power would this possibly be? Therein lies the crux of the issue. No one is in charge and I would not vote the government the power to regulate more. Rule by bureaucracy is is not necessarily beneficial to a free market.

I think the arguments on the many sides of this issue are all worth listening to and understanding. At the heart of all of this, is the market for diamonds and the faith consumers place in vendors and laboratories. Anything that can be done to increase consistency of grading without detroying the value and marketability of the product is worth consideration. Anything destructive of value or of questionable in consistency, are things that should not be considered. Diamond grading can be very accurate, but marketing is not just cold science. Diamonds bridge these two fields in very unique ways.

 

[windowshopper]

YES BUT IT BE A GREAT PUBLIC AWARENESS CAMPAIGN

 

[kevinraja]

Appraisers and vendors on this site probably hate us (Windowshopper, Regular Guy, ... and myself) as we try to reveal and discuss the ins and outs of the trade, which they might actually prefer us not to do.

I notice one thing, anytime a consumer raises a serious and a thoughtful question, it always happens that these appraisers and vendors RUSH to answer/knock them off by using the "most often used excuse word" subjective/objective.