How long does it take to grade a stone?

[kenny]

Does anyone know how much time is allowed to grade a diamond at the big labs like the GIA, AGS and EGL?
Is the gemologist given a certain number of stones per day?

Would it take longer to grade an IF than, say, an SI1?
Does a small stone take longer than a larger one?

Do human eyes make every decision, or do they use machines to judge, say, color?
Isn't this a very physically and mentally fatiguing to do this for 8 hours a day?
Wouldn't it be human nature to be less accurate as the day dragged on, or on Friday afternoon, or just before a vacation?
Does a second person check the first person for every report?
If so, does the second person see the first report and verify the first gemologist's grades or would he or she start from scratch without the pressure and politics of agreeing or disagreeing?

Are there a lot of repetitive stress injuries with these workers?

Do you suspect all labs allow the same time for grading?
Or, do some take their time to be more certain of the grades, while others are more driven by volume and speed?

 

[kenny]

bump

 

[Mara]

kenny seems like most of the experts are in Vegas so it may take a little while to get an answer...

 

[RockDoc]

I think it depends on many factors.

Does it take longer for an IF /FL stone?... sure it does, at least with me it does, as one pinpoint missed would totally screw up the grading. I think when exceptional stones ( or really large ones or fancy colors ones) are submitted they are reviewed. A lab wouldn''t want to be incorrect when grading a notable diamond.

The major labs do handle things in a "production" style fashion, so I''ve heard.

I''ve heard that IGI is almost akin to being a ''sweat shop'' for their graders.

Does more than one grader look at stones? I believe so, as I''ve been told that in some labs - some graders just do proportions, some do color, and other clarity. I''ve also heard that when there is a question, other opinions from other graders or supervisors also are used.

In the commercial labs, time is of the essence. I think a lot of the dealers are in a rush and don''t want their stones tied up too long. AGS does grade stones within 5 business days, GIA has a backlog all the time, so it takes weeks, although you can get rush service sometimes.

I think as a very generalized guideline, graders have about 30 minutes per stone.

I''ve never worked at any of the major labs, so all of this is just comments over the years that I''ve heard, so accept what I''ve written in that spirit, as things could have changed too.

Rockdoc

 

[Richard Sherwood]

Date: 6/1/2006 1:54:15 PM
Author:kenny
Does anyone know how much time is allowed to grade a diamond at the big labs like the GIA, AGS and EGL?

The time varies according to the complexity of the stone and degree of responsibility involved in it. Most graders are going to finish a $1,000 0.50 carat a lot quicker than a $100,000 5.00 carat. I agree with RockDoc's estimate of 30 minutes as an "average".

Is the gemologist given a certain number of stones per day?

I don't know, but I would suspect they are given a quota each day which they try to accomplish.

Would it take longer to grade an IF than, say, an SI1?

Yes, much longer.

Does a small stone take longer than a larger one?

No, it's usually the other way around.

Do human eyes make every decision, or do they use machines to judge, say, color?

All final decisions are made with the human eye, while machines may (and probably do) contribute to the color grading process & certainly to the proportion grading process.

Isn't this a very physically and mentally fatiguing to do this for 8 hours a day?

Yes. You have to pace yourself and take breaks. I typically take a 10 minute break every hour, meditating and "relaxing" my eyes.

Wouldn't it be human nature to be less accurate as the day dragged on, or on Friday afternoon, or just before a vacation?

Yes. Most graders try to get all their color grading done in the morning hours, when their eyes are the freshest. Clarity and proportion grading can be done no problem in the afternoons, as they don't require the intensity of focus that color grading does.

Does a second person check the first person for every report?
If so, does the second person see the first report and verify the first gemologist's grades or would he or she start from scratch without the pressure and politics of agreeing or disagreeing?

From what I understand, the GIA has two junior graders grade each stone independently, with their work reviewed by a senior grader. The senior grader is the "tie breaker" in any disagreements of grading. The senior grader also grades important high value stones as well.

Are there a lot of repetitive stress injuries with these workers?

I would suspect that eye strain is probably your most common injury. It's almost a Zen thing to learn how to relax your eyes, and not strain them.

Do you suspect all labs allow the same time for grading?
Or, do some take their time to be more certain of the grades, while others are more driven by volume and speed?

I suspect that labs which are driven foremost by accuracy and integrity take more time than labs which are driven foremost by profit.

That would certainly seem to be the case judging from the wide range of quality control I've witnessed between the different lab's work.

 

[Modified Brilliant]

Does more than one grader look at stones? I believe so, as I''ve been told that in some labs - some graders just do proportions, some do color, and other clarity. I''ve also heard that when there is a question, other opinions from other graders or supervisors also are used.
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I''ve heard that said also, Rockdoc. The first lab person "measures the diamond." I was surprised a few months ago when the depth of a lab graded stone was way off on the measurements. If you can''t get that right...that''s sending a negative message about the info on the rest of the report. You absolutely can never take anything for granted. Great questions and great answers, guys!

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