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 » RockyTalky
»  » Checking CUT grades on older GIA reports.....Interesting
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Checking CUT grades on older GIA reports.....Interesting |
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| P: 1/22/2006 12:45:57 AM | |
Garry H (Cut Nut) Ideal Rock Total Posts: 11,586 Last Post: 11/25/2009 Member Since: 8/16/2000 |
First find the certificate # and Carat weight from any site that lists diamonds with report info Enter the data here http://reportcheck.gia.edu/ and click retrieve You will see a page that lists the new cut report data. (Rarely there will be no info - just a note to say something like "this stone must be sent back to the lab") I looked up a few stones on GOG and then ran the data thru http://facetware.gia.edu/ In a few cases I got conflicting grades - the lab seems generally a bit tougher than Facetware - this could be a curse for manufacturers? Some examples http://www.goodoldgold.com/1_23ct_e_vs2.htm report 14780212 1.23ct C35.5 P41.2 T59% DEpth 62.2 VG by lab Ex by Facetware http://www.goodoldgold.com/1_35ct_h_si1.htm Report 14276146 1.35ct C 34.5 P41.4 T55% Depth 62.6% Medium Girdle This gets VG on both Facetware and the new Lab report - but if you drop the depth % by 0.1% it gets Excellent. So a diamond with a GIA medium girdle can have too poor a spread? I invite other to play and post their results here 
Garry Holloway FGAA DipDT HCA and Ideal-scope developer http://www.ideal-scope.com and http://www.HollowayDiamonds.com.au |
| Posted: 1/22/2006 12:45:57 AM | |
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There are 12 replies to this message. There are 12 replies on this page. |
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| P: 1/22/2006 1:08:08 AM | |
strmrdr Ideal Rock Total Posts: 23,296 Last Post: 10/9/2009 Member Since: 11/1/2003 |
gia new cert: http://www.goodoldgold.com/1_24ct_h_vs1_h%26a1.htm ........... Karl has joined the diamond trade and is now posting as Karl_K |
| Posted: 1/22/2006 1:08:08 AM | |
| P: 1/22/2006 3:57:13 AM | |
valeria101 Ideal Rock Total Posts: 14,048 Last Post: 4/30/2006 Member Since: 8/29/2003 |
wrong post... Ana "The greatest experts are only as good as the sum total of what they have seen." [Souren Melikian] |
| Posted: 1/22/2006 3:57:13 AM | |
| P: 1/22/2006 3:27:41 PM | |
Paul-Antwerp Ideal Rock Total Posts: 1,911 Last Post: 11/24/2009 Member Since: 9/3/2002 |
Indeed, very interesting, Garry.
Paul Slegers |
| Posted: 1/22/2006 3:27:41 PM | |
| P: 1/22/2006 3:41:17 PM | |
Serg Ideal Rock Total Posts: 1,519 Last Post: 11/25/2009 Member Since: 3/22/2002 |
re:http://www.goodoldgold.com/1_23ct_e_vs2.htm report 14780212 1.23ct C35.5 P41.2 T59% DEpth 62.2 VG by lab Ex by Facetware Garry< What girdle did you use In Facetware? try 5% Sergey Sivovolenko |
| Posted: 1/22/2006 3:41:17 PM | |
| P: 1/22/2006 6:06:39 PM | |
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Garry H (Cut Nut) Ideal Rock Total Posts: 11,586 Last Post: 11/25/2009 Member Since: 8/16/2000 |
Date: 1/22/2006 3:41:17 PM
Author: Serg re:http://www.goodoldgold.com/1_23ct_e_vs2.htm report 14780212 1.23ct C35.5 P41.2 T59% DEpth 62.2 VG by lab Ex by Facetware Garry< What girdle did you use In Facetware? medium and entered 62.2% which calculated 4% - but when I raise the stones depth % to 62.5% the girdle thickness goes to 4.5% and the stone drops down to VG. The next drop comes at 63.9% which is girdle 5.5% try 5% Why? Garry Holloway FGAA DipDT |
| Posted: 1/22/2006 6:06:39 PM | |
| P: 1/23/2006 3:02:59 AM | |
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Serg Ideal Rock Total Posts: 1,519 Last Post: 11/25/2009 Member Since: 3/22/2002 |
Date: 1/22/2006 6:06:39 PM 61.9-14.3-42.8=4.8
Author: Garry H (Cut Nut) Date: 1/22/2006 3:41:17 PM Author: Serg re:http://www.goodoldgold.com/1_23ct_e_vs2.htm report 14780212 1.23ct C35.5 P41.2 T59% DEpth 62.2 VG by lab Ex by Facetware Garry&lt; What girdle did you use In Facetware? medium and entered 62.2% which calculated 4% - but when I raise the stones depth % to 62.5% the girdle thickness goes to 4.5% and the stone drops down to VG. The next drop comes at 63.9% which is girdle 5.5% try 5% Why? Sergey Sivovolenko |
| Posted: 1/23/2006 3:02:59 AM | |
| P: 1/23/2006 7:14:07 AM | |
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Garry H (Cut Nut) Ideal Rock Total Posts: 11,586 Last Post: 11/25/2009 Member Since: 8/16/2000 |
Date: 1/23/2006 3:02:59 AM Author: Serg Date: 1/22/2006 6:06:39 PM 61.9-14.3-42.8=4.8Author: Garry H (Cut Nut) Date: 1/22/2006 3:41:17 PM Author: Serg re:http://www.goodoldgold.com/1_23ct_e_vs2.htm report 14780212 1.23ct C35.5 P41.2 T59% DEpth 62.2 VG by lab Ex by Facetware Garry&amp;lt; What girdle did you use In Facetware? medium and entered 62.2% which calculated 4% - but when I raise the stones depth % to 62.5% the girdle thickness goes to 4.5% and the stone drops down to VG. The next drop comes at 63.9% which is girdle 5.5% try 5% Why? 1. GOG Ogi scanner is always 0.2 degree too shallow on pavilion. 2. If you use #'s from GIA report and dimensions and make weight correct - you get 3.6% girdle. Garry Holloway FGAA DipDT |
| Posted: 1/23/2006 7:14:07 AM | |
| P: 1/23/2006 7:21:31 AM | |
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Serg Ideal Rock Total Posts: 1,519 Last Post: 11/25/2009 Member Since: 3/22/2002 |
re:2. If you use #'s from GIA report and dimensions and make weight correct - you get 3.6% girdle. It is incorrect operation for nonstandard girdle. Sergey Sivovolenko |
| Posted: 1/23/2006 7:21:31 AM | |
| P: 1/23/2006 8:57:19 AM | |
oldminer Ideal Rock Total Posts: 4,966 Last Post: 11/24/2009 Member Since: 9/4/2000 |
Since 1986 I published parameters for use as screening tools for finding the general quality of the cut for various shaped diamonds. People from all around the world quietly adopted these parameters, but most were smart enough to take into account their inherent limitations. We've made tens of thousands of AGA-CERTs with these grades without ever having a problem with a consumer or a dealer. Now the GIA is supporting their notion that you can purely determine the quality of cut by making more measurements. However, in rounding off measurements and additionally taking into account the degree of machine error, they now want to suggest their "grade" has the substance to make it more than a screening tool. Somehow, I doubt the validity of the end result will be more than "a useful screening tool". Before you know it, people will be saying something like, "Well the grade is a very good one, but you must examine the stone with your own eyes, to be sure it is a great stone." If this happens, then we'll all know that their system has problems and is misused except for screening. It seems as if the cutters and researchers here already think there are problems. Maybe the GIA ought to look again at their methodolgy and perfect things before they make a larger problem for themselves and the trade, too. This may delay their grading program for a few months or a year, but we've waited so long, it ought to be "the best" when its finally offered. Then again, we do have alternatives, but I think everyone was hoping for a meticulous and useful job to be done by GIA. David S. Atlas |
| Posted: 1/23/2006 8:57:19 AM | |
| P: 1/23/2006 10:46:48 AM | |
sylvesterii Cut Rock Total Posts: 295 Last Post: 5/27/2009 Member Since: 11/3/2002 |
perhaps I am doing something wrong, or perhaps the diamond report is too old (2002), but I don't get any more info than what was included on the original GIA diamond report...
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| Posted: 1/23/2006 10:46:48 AM | |
| P: 1/23/2006 10:54:53 AM | |
Rod Ideal Rock Total Posts: 3,260 Last Post: 11/24/2009 Member Since: 12/28/2005 |
I had the same issue, except my stone was graded by the GIA in September of 2005. I wonder why it would not provide the updated information for a stone so recently graded??
"Got Diamond? |
| Posted: 1/23/2006 10:54:53 AM | |
| P: 1/23/2006 10:58:58 AM | |
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Serg Ideal Rock Total Posts: 1,519 Last Post: 11/25/2009 Member Since: 3/22/2002 |
re:the lab seems generally a bit tougher than Facetware The GIA Facetware™ Cut Estimator is intended to provide an estimation of the cut grade that would be received from the GIA Laboratory for the same diamond. However, there are several reasons why the grade provided by GIA Facetware™ may be different from that received from the GIA Laboratory. Some of the reasons are: The diamond's actual proportions (such as the crown angle or star length) or visually assessed parameters (such as the girdle thickness or symmetry) as determined by the GIA Laboratory are different from the proportions or parameters assumed by the user. The diamond has been manufactured using non-standard brillianteering such that it is significantly "painted" or "dug-out" (i.e., the diamond has its upper- and/or lower-half facets fashioned at tilt angles different from those traditionally used for standard round brilliant diamonds). Click here to learn more. The accuracy and tolerances of different methodologies and optical devices used to measure a diamond's proportions or parameters may differ from those used by GIA. Click here to learn more. Sergey Sivovolenko |
| Posted: 1/23/2006 10:58:58 AM | |
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