A question for appraisers

[kenny]

The same stone sent to GIA, then AGS, then EGL is likely to come back with different ratings.
We all know that is the unfortunate truth.

Let's say I send you a stone, with no lab report.
Let's say you give it F VS1.
Which criteria do you use?
AGS, GIA, EGL, other?

Do you state the criteria on the report.
Do you write something like: F VS1, (per GIA's criteria)?

 

[RockDoc]

Hi Kenny

Really good question.

I''d say you have to ask each appraiser what they do. Although I''d surmise that most use the GIA basis for grading

Keep in mind though that clarity grading "loosens up" on diamonds weighing more than 1.50 carats

I grade using the GIA description /nomenclature for clarity color, but AGS as well as some others for proportion analysis. I do not subscribe or practice using the SI-3 grade.

However not every shape has a cut grade, so there I use my own judgment and talk with each client with the description and when applicable the result of the B Scope Analyzer and Viewer, and the Firescope.

Rockdoc

 

[oldminer]

Because until very recently there was no choice at all, diamond dealers and regular people from most places were forced into using the GIA as the "standard". It isn't a terrible choice, but it is not a perfect system. There is a degree of subjectivity as to where to cross a line from one grade to another when the call is "close". No matter how well you fine tune such a system, there ALWAYS will be arguments over near misses to the next better grade. If a dealer is lucky he gets the better grade. If the consumer is lucky, they get the better diamond with the next lower grade.

In the end, the average is that people get pretty much what they are paying for.....It isn't quite perfect, but the market is a very free and smart one, where the dollars asked are often adjusted to the proper grade regardless of the paper. It is a competitive reality that prices reflect the free market along with the reputation of each lab for being not only exacting, but how stiffly they grade.

Getting the strictest grade does not change the diamond from having the same diamond get slightly higher grading from a slightly less stiff grading lab. The value may appear to change, but the asking price will likely reflect how the dealer feels the grading is. A strictly and accurately graded diamond sets the standard. Over or Under graded diamonds command somewhat different prices depending on which lab and how much someone wants to spend. It is NOT EXACT.

We can now grade round diamonds in my lab for color grade using a statistical database and technological ImaGem equipment that gives GIA type results with a higher degree of consistency than human grading. It is capable of decreasing the number of borderline situations in color grading better than the human eye of graders. There are still, and always will be, borderline calls until we accept the fact that the D to Z color scale has too few steps to eliminate those problems. Eventually there will be color grading numerically, I suppose. Then the steps will be very small and there will be no subjective grading of color.

What we have now, D to Z, works very well in a free market, but it is just not perfect.. Human grading is certainly "good enough". Few things are truly objective and perfectly done.

 

[Regular Guy]

A couple of things are interesting about this.

First, Kenny, I''m not sure if this was your question or not, but...are you asking if a "color" is defined differently by different labs...or are you asking about how the application of one standard varies from one lab to the other?

From the structure of your question, it sounds like the former. But, from the nature of the responses, and what I think is the case, is that the latter is true, and there is one...if I''m not mistaken...GIA standard, based on what has come to be used as a referent GIA master set, and that all reference for color is known to point to, regardless of a pattern of application from one or another lab.

So, the interesting thing, however incidental, would be the training of, say, EGL non-USA lab techs. For example, in Grading Survey sponsored by Pricescope, EGL USA, is pulled out and compared to GIA (and AGS), and the suggestion is that you might only get a one grade bump from EGL USA. With this said, what are the implication from EGL Israel, or non USA. Three grades of difference? And likewise, again, try to imagine a Saturday Night Live skit where a new hire is going through training:

Manager: ...comparing that diamond to the master set, what do you see.
New Hire: that looks like a J to me
Manager (lifts his eyebrows)
New Hire: I?
Manager (lifts his eyebrows)
New Hire: H
Manager (hands on hips and frowns)
New Hire: by god that''s a G, isn''t isn''t?
Manager goes to shake hands of their new employee.

So, would it work something like that?

 

[Richard Sherwood]

Date: 7/15/2005 12:14:10 PM
Author: oldminer

We can now grade round diamonds in my lab for color grade using a statistical database and technological ImaGem equipment that gives GIA type results with a higher degree of consistency than human grading. It is capable of decreasing the number of borderline situations in color grading better than the human eye of graders.

I'm not sure I would trust a machine's estimate of borderline grading over the human eye. I think the day has not yet arrived where a machine even begins to approach the precision and accuracy of the trained human eye.

The eye and brain of the average man can distinguish 800 shades of gray, while that of the average woman can distinguish 1100 shades. Does this Imagem even come close to that kind of precision?

I doubt it.

The only way to get the industry to begin to accept the ImaGem, is to make it widely available for independent scrutiny. Until then, it will be an unknown, with no widespread credibility.

 

[MissAva]

Date: 7/17/2005 10:40:37 PM
Author: Regular Guy
A couple of things are interesting about this.

First, Kenny, I''m not sure if this was your question or not, but...are you asking if a ''color'' is defined differently by different labs...or are you asking about how the application of one standard varies from one lab to the other?

From the structure of your question, it sounds like the former. But, from the nature of the responses, and what I think is the case, is that the latter is true, and there is one...if I''m not mistaken...GIA standard, based on what has come to be used as a referent GIA master set, and that all reference for color is known to point to, regardless of a pattern of application from one or another lab.

So, the interesting thing, however incidental, would be the training of, say, EGL non-USA lab techs. For example, in Grading Survey sponsored by Pricescope, EGL USA, is pulled out and compared to GIA (and AGS), and the suggestion is that you might only get a one grade bump from EGL USA. With this said, what are the implication from EGL Israel, or non USA. Three grades of difference? And likewise, again, try to imagine a Saturday Night Live skit where a new hire is going through training:

Manager: ...comparing that diamond to the master set, what do you see.
New Hire: that looks like a J to me
Manager (lifts his eyebrows)
New Hire: I?
Manager (lifts his eyebrows)
New Hire: H
Manager (hands on hips and frowns)
New Hire: by god that''s a G, isn''t isn''t?
Manager goes to shake hands of their new employee.

So, would it work something like that?

LOL!!!

 

[JohnQuixote]

LOL Ira.

 

[RockDoc]

Interesting Skit Ira.

But in reality, and competent diamond grader who can''t separate a G from a J, needs a seeing eye dog.

or maybe its better said that would be "WILLFULLY BLIND"!

Rockdoc