What are GIA criteria diamonds?

[hairgirl95]

This may be a dumb question, and I searched the old posts about this but didn''t really find a true answer. My question is this: GIA is by far the most respected grading lab. So, do they only grade TOP diamonds?? Such as, if you purchase a GIA certed stone, it is because that stone is much better than most of the other stones out there? I ask this because of the current diamond hunt I am on. If I pick a GIA stone I like, is it a top QUALITY stone since the GIA cert is attached?? Will GIA grade a not so great stone? Sorry if this is confusing, I hope you all understand what I am asking. I refuse to do this upgrade unless its a GIA cert stone, (per everyone''s advice here) so I am wanting to make sure I am understanding this. Thank you and I hope this wasn''t too confusing.

 

[Erik Carlson GG]

GIA will grade the good the bad and the ugly. Just because the stone is GIA does not make it a higher quality.

That said, quality for quality GIA certed stones will trade for much higher value than other certification companies.

 

[hairgirl95]

Thanks Erik that is EXACTLY what I was looking for! I needed some clarification on it.

 

[surfgirl]

As Erik said, GIA grades all types of stones and has no way of knowing what they''re getting in to grade when they receive a stone so yes, it can be anything from a D/Flawless, to a M+/I3 whatever...But what getting the GIA cert DOES do is tell you that it is pretty certain that what the stone was graded at in GIA, is most likely what the stone really is. If you compare a stone cert''d from EGL Israel, for example, and EGL G/SI2 could end up really being a I/J I2 if you sent the same stone to GIA. So you''re getting a stone that''s held up to a higher, more stringent standard that EGL or other certification labs. And the reason a GIA stone might command a little higher price is simply because there''s less wiggle room for someone else to say "well, actually this stone is a lower grade", etc. With GIA, hopefully WYSIWYG.

 

[Lorelei]

Date: 2/20/2008 1:08:05 AM
Author:hairgirl95
This may be a dumb question, and I searched the old posts about this but didn''t really find a true answer. My question is this: GIA is by far the most respected grading lab. So, do they only grade TOP diamonds?? Such as, if you purchase a GIA certed stone, it is because that stone is much better than most of the other stones out there? I ask this because of the current diamond hunt I am on. If I pick a GIA stone I like, is it a top QUALITY stone since the GIA cert is attached?? Will GIA grade a not so great stone? Sorry if this is confusing, I hope you all understand what I am asking. I refuse to do this upgrade unless its a GIA cert stone, (per everyone''s advice here) so I am wanting to make sure I am understanding this. Thank you and I hope this wasn''t too confusing.

Also FYI, AGS is the other top tier lab, so you may want to consider diamonds which have an AGS report also.

 

[Allison D.]

Hair, both AGS and GIA are considered very reputable labs. In both cases, they enjoy solid reputations for grading accuracy relating to color/clarity.

AGS enjoys a slightly more elite reputation as far as cut grading goes because they were the first lab to actually grade the cut of a stone, and they maintain a pretty strict criteria for what gets their top grade.

In the last few years, GIA has also begun grading cut, but their criteria for earning a top cut grade is much broader (more lenient?)

An AGS grading report tends to cost more because it's perceived to be 'more elite' by those who are cut-obsessed due to stricter cut-grading paramaters. If a dealer knows a given stone isn't likely to earn the elite cut grade, it doesn't make sense to pay the premium to obtain an AGS grading report. As such, it stands to reason that most of the stones submitted to AGS are expected to hit the elite cut grade status.

GIA didn't provide cut grading until the last few years. Also, their grading reports are less expensive than GIA, and the GIA name is more familiar to consumers. Accordingly, it makes sense they receive a broader range of stones to grade....they grade stones across a broad spectrum including top-make, above average make, and average make stones. They don't grade only top make stones.

Dealers who deal in various makes might to send all their goods through GIA instead of breaking them out among different grading labs. Accordingly, it's possible that some GIA ex stones would also earn the elite AGS0 grade if they went to AGS, but the dealer chooses to do business with GIA due to their good business relationship and for convenience.

From a consumer standpoint, you can take comfort in knowing that both labs are considered quite accurate in terms of color and clarity grading. While both vary a bit on ideology regarding cut, they are still both light years ahead of most others.

 

[hairgirl95]

I am understanding this MUCH better now! Its about the accuracy of the grading. Now I see why everyone says to go with the GIA or also the AGS. It makes total sense. You are really getting what the cert says, not manipulated numbers. I was a little confused about whether or not top tier graders would put a cert out on a not so great diamond. You all did great answering my question! Thank you all!

 

[oldminer]

Allison; I always get the slight feeling of a hot poker when a member of the trade says that the AGS lab was "the first" to grade the cut of diamonds. They clearly were not first. This is something they can get away with claiming because of their size and advertising, but it isn''t so. Peter Yantzer is a good guy and AGSL has taken back this claim a couple times where they made it and I raised an objection.
AGSL is the first large scale lab to offer cut grading, but my old lab, AGA was grading 9000 or more diamonds a year for several years before AGSL graded cut. AGA was grading Cut before there was an AGSL. I don''t blame you for not knowing. I could only wish I had enjoyed the wide acclaim AGSL has earned since they opened. They do a very fine job and I am not a resentful person.

 

[Allison D.]

Dave, you know it isn't my intention to give you the 'hot poker' effect.

My comments were really more meant to comment on the 'large-scale' labs; I'm sorry if it didn't come through that way.

 

[oldminer]

I know. No problem. My sensitivity buttons are turned up today. Just having too much fun for one day!

Diamond has inherent hardness, luster and optical properties which led those who developed the round ideal range, such as Tolkowsky and Morse, etc to cut it within fairly narrow guidelines. They did not all perfectly agree with one another, but nearly all of them are closely packed into a reasonably distinct range. I found that these properties make cutting fancy shaped diamonds cluster within certain ranges, too. Fancy shapes have so many more variables of shape that cutting parameters don''t dictate the entire result, but there are clearly certain similar, inherent things about beautiful diamonds which are never missing in any shape, round or fancy. This set of principals led to the AGA Cut Class system and now into the DFS system recently publsihed in the Rapaport Feb 08 edition. This article got sandwiched in between an article about AGS and one about GIA.....not a bad position being the meat in the sandwich.

The great stones from vendors like Whiteflash get the highest AGA grades, so no worries. We were grading such diamonds long before the Internet ever had any effect on the diamond business.