GIA classes of cuts

[simpleplan]

Hi, all

I am confused when someone told me that the diamond I am about to purchase has AGS ideal 000 has GIA class IV cut. I know that GIA system is now using EX-EX-EX and AGS used Ideal 000.

I read the Fred Cuellar book about diamond. He did mention about GIA class I and II are well-proportioned and class III and IV which cost way less for the price.

Is AGS ideal 000 equal either GIA class I or II?

The seller also told me that if the total depth percentage of the diamond cut over 61% is considered as GIA class III or IV. What is standard total depth percentage of a well-proportioned cut diamond?

Any ideas on this?

Thanks

 

[JulieN]

there is no such GIA class organization.

62 or 62.3 are generally cutoff ceilings, as if you go more than that, you start losing spread, but there are tradeoffs.

 

[simpleplan]

Date: 10/23/2007 11:14:56 PM
Author: JulieN
there is no such GIA class organization.

62 or 62.3 are generally cutoff ceilings, as if you go more than that, you start losing spread, but there are tradeoffs.

The seller insisted the perfect cut of the total depth should below 61% since they tend to cut deeper to make the diamond heavier

The book also wrote if the total depth percentage over 61% is not a well-proportioned

 

[JulieN]

you can have a well-proportioned stone at 63%. it''s all about the combination.

 

[diamondseeker2006]

I would suggest that the book is not up-to-date or else it is incorrect (and the same with the seller, apparently). Please use this site for current cut information under the Knowledge section. Also, if you put in your diamond''s table, depth, crown and pavilion angles into the cut advisor under Tools, you can see where AGS0 and GIA Excellent fall. GIA Excellent is broader, so you have to be more selective when looking at GIA Excellents.

 

[DiamondExpert]

Just make sure you don''t get a warped diamond

!!

 

[Chase035]

Step 1: Read everything under knowledge here.
Step 2: Have a look at the cut adviser under tools above or just look up holloway cut adviser on google.

I remember reading some of Fred''s stuff. He is good but I believe the book you are reading now is old. GIA has recently changed their grading system. The cut adviser will clue you in to help demonstrate when a larger depth is acceptable. It is true that long depths for the same carat weight usually result in smaller diameter stones. But what you really want to look at are the crown and pavillion angles in addition to the depth and table. The cut adviser is good for this.

 

[gbreaux]

hi,

i found this board the same as you. .. because i was being told by DCI (Fred Cuellar) that every diamond i found was a class IV and also probably warped...and oh why wasn''t my H or G being graded 1 - 5. and why wasn''t it...probably because the vendor was trying to hide something no doubt.

and then they would send me their megascope with H 1 on it plain as day. they said i could get a 1 H and this would be as good as G 5. they said they were just trying to save me money. confusing huh??

am i glad i found this board before buying from these shmucks!!

they recently sent me one of their books just for corresponding w/ them about diamonds i was considering for purchase.

i wish i could tell you what the book was like, but i threw in the trash unopened.

i recently purchased a totally "cut up" 1.02 G / VS1 from Good Old Gold here on this website and am awaiting the ring now.

it''s in; i''m just waiting for the diamond to be laser inscribed because it has no visible inclusions and i need to be able to identify it some way.

advice: just relax now and let these good people help you out.

do a search for gbreaux and you''ll see what i mean. these schmucks told me the diamond i''m buying now is class IV. what a joke these people are!!!!

i''ll try to upload a pic of the ring.

 

[oldminer]

The GIA once taught the four classes of cut grading for round diamonds. I doubt they do it today although other information surrounding cut quality is certainly part of the educational process. Rapaport uses cut class A, or C. These are wide cut grade ranges, much like the old GIA 4 class system and have some importance, mostly to cutters and dealers.

Advice that there was no four cut classes taught by GIA is wrong information. They never used this in their lab because no dealers wanted more information provided on reports. I am sure many dealers still want more information to be kept hidden, but the genie is out of the bottle. To my way of thinking, it was long overdue.

 

[simpleplan]

gbreaux,

That is good. The DCI also insisted that they have the best cut diamond. They always say the other people diamond is not cut well. They G5 and H1 are confused the heck out of me until I found this website and the HCA which is execllent to check for the proportion.

DCI also sell some very expensive diamond if you don''t know what you are looking for.

 

[JohnQuixote]

Date: 10/24/2007 8:06:07 AM
Author: oldminer
The GIA once taught the four classes of cut grading for round diamonds. I doubt they do it today although other information surrounding cut quality is certainly part of the educational process. Rapaport uses cut class A, or C. These are wide cut grade ranges, much like the old GIA 4 class system and have some importance, mostly to cutters and dealers.

Advice that there was no four cut classes taught by GIA is wrong information. They never used this in their lab because no dealers wanted more information provided on reports. I am sure many dealers still want more information to be kept hidden, but the genie is out of the bottle. To my way of thinking, it was long overdue.

Just a few years ago it he was still in there, well-capped, stuffed under a pillow (with the occasional poof of AGS smoke leaking out). GIA uncorked the bottle themselves in 2006.