GIA''s amazing new patent

[adamasgem]

I just randomly grabbed a NEW GIA (NEW ARITHMETIC), cert from a web site..

CH=15%
Table=55%
CA=34.5%

Mathematics says 33.69 degrees GREAT CONSISTENCY, AND THEY ARE GOING TO PATENT THIS...


BUYERS BEWARE, DON'T TRUST WHAT IS ON THE GIA PAPER...

This is what half assed rounding does to you, what number is correct, if any. NOTE the words "profile is to actual proportions" yah... right......
.

 

[adamasgem]

The Green Blocks below ort of show where the "truth" may lie, based on the nearest half degree round of the crown angle, nearest 0.5% for crown height and nearest 1% for table size "rounding" criteria.. If the have the "real" average numbers, why don''t they print them out using conventional rounding. FarceWare(TM) can do the lookup without pre rounding.. STOOPID

 

[RockDoc]

Hmmmm...


"Actual"?????????? Are they back to that again?


What''s actual about an AVERAGE ???, then add insult to injury by rounding up/down!!!!!

It''s bad enough that there is some variance in the Sarin/Ogi etc.

A triple decker whammy?????

Guess now we all have to check the math on GIA reports..... hmmmmm.

Rockdoc

 

[Serg]

Date: 1/24/2007 6:34:13 PM
Author: adamasgem
I just randomly grabbed a NEW GIA (NEW ARITHMETIC), cert from a web site..

CH=15%
Table=55%
CA=34.5%

Mathematics says 33.69 degrees GREAT CONSISTENCY, AND THEY ARE GOING TO PATENT THIS...


BUYERS BEWARE, DON''T TRUST WHAT IS ON THE GIA PAPER...

This is what half assed rounding does to you, what number is correct, if any. NOTE the words ''profile is to actual proportions'' yah... right......
.

BTW. GIA uses very strange way to mark crown and pavilion Heights on plot.
What is connection between two horizontal lines( girdle model in 2D part plot) and 3D girdle shape( Is it for bezel level ?)

 

[adamasgem]

Date: 1/25/2007 3:06:48 AM
Author: Serg

BTW. GIA uses very strange way to mark crown and pavilion Heights on plot.
What is connection between two horizontal lines( girdle model in 2D part plot) and 3D girdle shape( Is it for bezel level ?)

Serg.. I think so... There are a few issues with the girdle...
1) Typically the girdle thickness is assesed at the minimums of the scallops which are inbetween the mains and the break junctions yet the diagram implies they are at the crown/pavilion main junction
2) The pavilion numerics suffer from the same numerical problem as the crowns because of the "rounding"
3) I sort of wonder how the crown data is computed, ther patent suggests that some numbers are "derived", but that doesn't make any sense .. Typically, I think in scanners methodology, angles are derived from linear measurements..
4) I'd have to do some thinking about the relative inaccuracies of the angles.. GIA's rounding of the pavilion angles is to the nearest even .2 degree increment and the crown main to the nearest half degree. The 2.5 to one implied uncertainty ratio might be consistent with uncertainties based on base length differences, but doesn't consider that one could use multiple line segments to determin the plane angle wrt the girdle plane.
1) A plane is uniquely defined by 3 points or 2 lines, however with measurement errors, and the fact that you have overdefined planes by virtue of multiple profile measurements, the methododology for determining angle uncertainties might well have the uncertainties of the crown and pavilion mains quite similar because, if you consider the crown mains versus the pavilion mains, the crown mains are much wider and contain more profile line segments than the pavilion mains.. So the rounding of the Crown angles to 0.5 degree seems overly conservative..

Can you comment on this please. Serg..

GIA reports on measurements seem next to useless, and their statement about "actual" proportions appears outright fraudulant. My underatnding, is based on an older Pricescope thread, and a published comment by Rockdoc in Modern, that they may have "corrected" this in newer paper. I believe the paper's example in the inet that I pulled was from April 2006.
Can anyone point me to some newer paper...RECALL...

Appraisers who use the paper's numbers in their description of the stone should clearly NOTE in their appraisal that the numbers have been averaged and the rounded and are NOT mathematically consistent, in stark contrast to the implied staements in the paper and in their patent application. The liberal use of the terminology "approximately" prior to ANY number is advised, something I've done for many years, and also ste the implied rounding criteria, as both appraisals and paper can be held to be legal documents subject to litigation. The qualitative assesment of SYMMETRY could be very suspect also, as the criteria is ill defined. Bill Brays Brayscore methodology is the only quantitative defined methodology that I have seen, and the AGS ASET photographs (as well as H&A and Firescope and Ideal Scope) certainly show asymmetry beter than any subjective statement on GIA reports. The absense of min-maxs on laboratory paper is eggregious, given the state of vastly improved scanner accuracy.
Or maybe GIA paper is a reflection of the relative accuracy of the Farceware(TM) scanner.

PS Anyone got a spell checker that works inside the PS input window

 

[JulieN]

RockDoc: https://www.pricescope.com/community/threads/gia-noticed.49633/

New report

 

[RockDoc]

Julie

That is interesting.... that this report dated this month is back to the "actual" reference again.

That is based on the methodology of what they report, misleading and fraudulent.

Simply stated the "numbers" aren''t actual.

Making decsions to purchase only relying on the numbers possibly may result in consumers getting something different than they relied on.

No statement is better than the "actual" one.

Methinks they must have a lot of extra kitty littter, and are digging into it deeper than they already have done.

Rockdoc

 

[adamasgem]

Date: 1/25/2007 12:28:51 PM
Author: JulieN
RockDoc: https://www.pricescope.com/community/threads/gia-noticed.49633/

New report

Thanks JulieN

"Profile to "actual" proportions", certainly not to the "actual" proportions of the stone, as as the numerics shown are not mathamaitcally consistent. The callaout is different than their advertizement in the Loupe stating that the diagram is the actual proportions of the stone.

Actual proprtions of WHAT???????

Intentionally misleading, if not outright fraudulant, in my opinion. And certainly NOT to the consistency implied and stated in their "amazing" patent application...

Typically GIA, saying one thing, and doing something entirely different..

Sounds like a class action to me.

Someone (consumer, trade) should forward this thread to the FTC.

And also Donna Baker..

She being a lawyer, should understand the implications $$$$$$ of this.

 

[adamasgem]

Here is an interesting comparison on a brand new painted girdle stone, the GIA report and a Sarin scan of the same stone.

Note the LACK of the "actual proportion" comment, and the incorrect rendering of the break facet heights on the GIA profile view rendering.

Makes you wonder whether when they have paper that says "actual proportions" whether or NOT the girdle profile is based on the "actual" min max's of the stone...

Inquiring minds want to know..

Great consistency with the stated objectives in their "amazing" patent application..

By the way, this stone, as well as others cut by the same cuter, have the best symmetry in girdle profiles I have ever seen. The Sarin scan of this stone is with Sarins new software which fixed previous problems with this class of stone.
Thank you Sarin for responding promptly to the industry's (and my) concerns.

BTW.. This is a bruted girdle stone, not a faceted as implied by the GIA diagram, and the culet on the pavilion view would show as such.

 

[Rhino]

Marty, can you forward me the .srn on that stone? I'd like to see and compare to my scans if you dont mind. In case you didn't catch it I had posted this comparison in another thread regarding the scanning of painted stones. Before and after with the updated Sarin. A world of difference regarding the meet point symmetry scan. I did get the update to the OGI but no change in results on that front.

 

[adamasgem]

Date: 1/25/2007 2:22:53 PM
Author: Rhino
Marty, can you forward me the .srn on that stone? I''d like to see and compare to my scans if you dont mind. In case you didn''t catch it I had posted this comparison in another thread regarding the scanning of painted stones. Before and after with the updated Sarin. A world of difference regarding the meet point symmetry scan. I did get the update to the OGI but no change in results on that front.

Done..

Pity OGI can''t get their act together, and they are in Bed with GIA... Makes you wonder what FarceWare(TM) is based on..

 

[adamasgem]

One interesting thing that I just noticed is that the left hand side of the profile view is a slice through the break facet junctions, instead of through the mains...

 

[stebbo]

Date: 1/23/2007 8:39:47 PM
Author: adamasgem

Do the arithmatic on the numbers in the graphic above on the patent..

Table 57%
Crown Height = 13.5%
Crown Angle 34.5 degrees
...
...
I don't believe MY arithmatic is wrong. Am I missing something?

I even went back and looked at their dummy charts, for those who can't use a calculator, in their new diamond grading Lab manual, and they have it correct there (within rounding error)

Even the largest rounding errors yields no more than 33 degrees of crown - maybe they didn't like their diamonds being called warped and now measure crown height from the girdle valleys?

You must admit, the figures add up!

Author: adamasgem

4) I'd have to do some thinking about the relative inaccuracies of the angles.. GIA's rounding of the pavilion angles is to the nearest even .2 degree increment and the crown main to the nearest half degree. The 2.5 to one implied uncertainty ratio might be consistent with uncertainties based on base length differences, but doesn't consider that one could use multiple line segments to determin the plane angle wrt the girdle plane.

I don't believe the 2.5:1 uncertainty ratio is because of measurement accuracies. Bigger stones can be measured more accurately than smaller stones, yet the rounding is consistent. Afterall, the crown on a ideal 2.5 carat is as long as the pavilion on an ideal 0.2 carat.

I could believe they're trying to incorporate typical angle deviations from the average into their measurements and the 2.5:1 is their (understated) opinion of the pavilion:crown relative sensitivities in affecting light performance.

I can definitely believe that like their wide 'excellent' attracts business, these roundings also increase the number of stones on the market that can get away with being 34.5/40.75's.

Stebbo

 

[strmrdr]

Date: 1/25/2007 12:14:24 PM
Author: adamasgem


PS Anyone got a spell checker that works inside the PS input window

http://toolbar.google.com/T4/index_xp.html?utm_source=en-et-more&utm_medium=et&utm_campaign=en

 

[Rhino]

I''ve been following this to an extent and see it''s gotten off the original topic and onto the rounding issue and thought I''d throw in my .02c. Firstly, I sympathize with the views being expressed. I like more detail and don''t hesitate to spend the funds to acquire them. However, if we are to really get particular about defining what are actual proportions or not I must ask ...

Consider the 4 scans below all taken from the same stone. 3 of these scans are from us and one is taken from an appraiser who owns a Sarin. Which of these scans, in your opinion represent the actual proportions of the diamond in question?

 

[adamasgem]

Date: 1/26/2007 7:44:50 AM
Author: strmrdr

Date: 1/25/2007 12:14:24 PM
Author: adamasgem


PS Anyone got a spell checker that works inside the PS input window

http://toolbar.google.com/T4/index_xp.html?utm_source=en-et-more&utm_medium=et&utm_campaign=en

Thank You Storm...

 

[strmrdr]

Date: 1/26/2007 3:18:08 PM
Author: Rhino
I've been following this to an extent and see it's gotten off the original topic and onto the rounding issue and thought I'd throw in my .02c. Firstly, I sympathize with the views being expressed. I like more detail and don't hesitate to spend the funds to acquire them. However, if we are to really get particular about defining what are actual proportions or not I must ask ...

Consider the 4 scans below all taken from the same stone. 3 of these scans are from us and one is taken from an appraiser who owns a Sarin. Which of these scans, in your opinion represent the actual proportions of the diamond in question?

The first and the last.
The first is most likely your sarin because its closer to the helium scan and for whatever reason you seem to get better results with yours than some do.
So within the limits of the sarin its the second most acceptable.

the last is a helium scan and the most accurate of the bunch and what I would consider the "true" measurements.

 

[strmrdr]

Have a question why does the ogi always seem to get the pavilion angle .2 degrees shallower than sarin are they measuring them different?
Or is the ogi just that lame?

 

[adamasgem]

Date: 1/26/2007 3:18:08 PM
Author: Rhino
I've been following this to an extent and see it's gotten off the original topic and onto the rounding issue and thought I'd throw in my .02c. Firstly, I sympathize with the views being expressed. I like more detail and don't hesitate to spend the funds to acquire them. However, if we are to really get particular about defining what are actual proportions or not I must ask ...

Consider the 4 scans below all taken from the same stone. 3 of these scans are from us and one is taken from an appraiser who owns a Sarin. Which of these scans, in your opinion represent the actual proportions of the diamond in question?

To use a Clintonesque phrase. "I guess it all depends on what the meaning of the word "actual" is..

All of the values are rounded averages, are typically rounded using standard decimal rounding conventions. INDIVIDUAL facets are not averages..

That is why I have asked SARIN to report angles, diamentions and averages to 2 decimal places...

In your examples the "differences" seen could represent calibration errors, run to run variances, or unit to unit variances, so the use of the wording "actual" should be avoided, and the computed uncertainty (or min max) for each measurement set presented, should be given.

There are always measurement errors, but they shouldn't be compounded by artificial rounding..

Just as one uses a Class "S" or better weight for scale calibration, users of scanners should have a reference stone to be used for calibration checking on a daily basis.....

Which scan is right, that is anyone's guess, as, at first glance, I can't guess, other than the last carries out the data to finer quantization, relative to the implied decimal rounding standards used..

There are many factors that have to be considered, firstly, whether all machines have been properly calibrated, and to what "standard(s)"

Secondly, most scanners have a fast and most accurate scanning mode. The most accurate mode looking at more "slices" of the diamond, which enables more accurate estimation of dimensions and angles.

Unfortunately, the trade typically likes the FAST option.

NONE is the technically "correct" answer to your question, regardless of "opinions"

 

[adamasgem]

Date: 1/26/2007 3:38:27 PM
Author: strmrdr

Date: 1/26/2007 3:18:08 PM
Author: Rhino
I''ve been following this to an extent and see it''s gotten off the original topic and onto the rounding issue and thought I''d throw in my .02c. Firstly, I sympathize with the views being expressed. I like more detail and don''t hesitate to spend the funds to acquire them. However, if we are to really get particular about defining what are actual proportions or not I must ask ...

Consider the 4 scans below all taken from the same stone. 3 of these scans are from us and one is taken from an appraiser who owns a Sarin. Which of these scans, in your opinion represent the actual proportions of the diamond in question?

The first and the last.
The first is most likely your sarin because its closer to the helium scan and for whatever reason you seem to get better results with yours than some do.
So within the limits of the sarin its the second most acceptable.

the last is a helium scan and the most accurate of the bunch and what I would consider the ''true'' measurements.

Good observation Storm.. I didn''t even think about which scanner was used for each picture..

 

[adamasgem]

Date: 1/26/2007 3:42:54 PM
Author: strmrdr
Have a question why does the ogi always seem to get the pavilion angle .2 degrees shallower than sarin are they measuring them different?
Or is the ogi just that lame? ====== GIA FarceWare(TM)????

 

[Adylon]

One thing I''d REALLY like to see on a grading report is some tolerances.

54.8 +/- 0.2% table, 62.7 +/- 0.3% depth or something to that affect.

It would be very nice if they gave tolerances of their human-observed grading as well, like clarity, color, etc, but I don''t think that''s going to happen any time soon because of all the politics surrounding that topic of course. But when something is measured by machine or gauge, why not specify what the precision of that tool is?

 

[adamasgem]

Date: 1/26/2007 4:29:57 PM
Author: Adylon
One thing I''d REALLY like to see on a grading report is some tolerances.

54.8 +/- 0.2% table, 62.7 +/- 0.3% depth or something to that affect.

It would be very nice if they gave tolerances of their human-observed grading as well, like clarity, color, etc, but I don''t think that''s going to happen any time soon because of all the politics surrounding that topic of course. But when something is measured by machine or gauge, why not specify what the precision of that tool is?

By "politics", you mean BIG money don''t you, and the opening up of bargaining positions or opportunities.. is it "really" a "D" or is it an "E" ??? That why everything is an "opinion" with no guaranties. When I developed my SAS2000 I institued confidence bounds on color grading, because we really don''t know the length of our "blessed" yardsticks.. Most in the trade consider their master stones sacrosanct, as absolutes, and they are not. One of the things that has been covered up (swept under the rug) for many years. I think I have covered this subject in another PriceScope thread before.

 

[adamasgem]

Date: 1/26/2007 3:38:27 PM
Author: strmrdr

Date: 1/26/2007 3:18:08 PM
Author: Rhino
I''ve been following this to an extent and see it''s gotten off the original topic and onto the rounding issue and thought I''d throw in my .02c. Firstly, I sympathize with the views being expressed. I like more detail and don''t hesitate to spend the funds to acquire them. However, if we are to really get particular about defining what are actual proportions or not I must ask ...

Consider the 4 scans below all taken from the same stone. 3 of these scans are from us and one is taken from an appraiser who owns a Sarin. Which of these scans, in your opinion represent the actual proportions of the diamond in question?

The first and the last.
The first is most likely your sarin because its closer to the helium scan and for whatever reason you seem to get better results with yours than some do.
So within the limits of the sarin its the second most acceptable.

the last is a helium scan and the most accurate of the bunch and what I would consider the ''true'' measurements.

Storm, one might surmise, that all other factors being equal, the presentation of more decimal places, makes the representation more accurate.
However, given other factors, such as methodology, that may NOT NECESSARILY be factual, although both you and I believe it to be so,

 

[Rhino]

Date: 1/26/2007 3:38:27 PM
Author: strmrdr

Date: 1/26/2007 3:18:08 PM
Author: Rhino
I''ve been following this to an extent and see it''s gotten off the original topic and onto the rounding issue and thought I''d throw in my .02c. Firstly, I sympathize with the views being expressed. I like more detail and don''t hesitate to spend the funds to acquire them. However, if we are to really get particular about defining what are actual proportions or not I must ask ...

Consider the 4 scans below all taken from the same stone. 3 of these scans are from us and one is taken from an appraiser who owns a Sarin. Which of these scans, in your opinion represent the actual proportions of the diamond in question?

The first and the last.

I happen to agree but then who are you or I to say?

The first is most likely your sarin because its closer to the helium scan and for whatever reason you seem to get better results with yours than some do.
So within the limits of the sarin its the second most acceptable.

You do happen to be one of the extremely rare exceptions of consumers who are familiar with the tolerances of both our Sarin and Helium scanners but what of the vast majority of people not aware of this? The additional Sarin I provided comes from a very reputable appraiser who is highly regarded in the industry. His Sarin is off by .2 on the pavilion and at least .1-.2 degrees on the crown of the actual proportions if we are to accept your answer. Of course he may argue differently and I would of course accept his right to disagree, however... who is to say? I think there is an answer to this solution but I want to play a little devil''s advocate here if we''re going to get this anal.

the last is a helium scan and the most accurate of the bunch and what I would consider the ''true'' measurements.

I agree strm but last I checked I''m one of the only labs in this country with one. Having all folks send stones here for an appraisal of true actual measurements is not practical and implies all others that don''t match it aren''t true or actual.

Marty hit the nail on the head in the next post I see when he states ... It depends on your meaning of the word "actual".

This begs the question ... Considering the variances of non contact measuring devices on the market today, is GIA being reasonable or unreasonable with their use of the word actual on their report?

Food for thought.

 

[Rhino]

Date: 1/26/2007 3:42:54 PM
Author: strmrdr
Have a question why does the ogi always seem to get the pavilion angle .2 degrees shallower than sarin are they measuring them different?
Or is the ogi just that lame?

It's algorythm for computing pavilion angles are different from Sarin/Helium to my knowledge. I don't have the details in front of me. Garry or Marty may know more of the details off the cuff.

 

[Rhino]

Date: 1/26/2007 5:00:14 PM
Author: adamasgem

Date: 1/26/2007 3:38:27 PM
Author: strmrdr

Date: 1/26/2007 3:18:08 PM
Author: Rhino
I''ve been following this to an extent and see it''s gotten off the original topic and onto the rounding issue and thought I''d throw in my .02c. Firstly, I sympathize with the views being expressed. I like more detail and don''t hesitate to spend the funds to acquire them. However, if we are to really get particular about defining what are actual proportions or not I must ask ...

Consider the 4 scans below all taken from the same stone. 3 of these scans are from us and one is taken from an appraiser who owns a Sarin. Which of these scans, in your opinion represent the actual proportions of the diamond in question?

The first and the last.
The first is most likely your sarin because its closer to the helium scan and for whatever reason you seem to get better results with yours than some do.
So within the limits of the sarin its the second most acceptable.

the last is a helium scan and the most accurate of the bunch and what I would consider the ''true'' measurements.

Storm, one might surmise, that all other factors being equal, the presentation of more decimal places, makes the representation more accurate.
However, given other factors, such as methodology, that may NOT NECESSARILY be factual, although both you and I believe it to be so,

Not sure if that was strm''s point, but you do raise a good point too Marty. Just because it''s reporting down to 1/100th of a degree doesn''t mean more accurate. We can detract from Sarin files down to 1/100th even when a Sarin is off.

 

[strmrdr]

You know something about my answer bugged me and after thinking about it...

Can average angles of 8 facets ever be considered true or actual?
None of the facets may actualy have that specific number.

 

[Rhino]

Date: 1/26/2007 5:16:33 PM
Author: strmrdr
You know something about my answer bugged me and after thinking about it...

Can average angles of 8 facets ever be considered true or actual?
None of the facets may actualy have that specific number.

Answer: Yes. The proper wording IMO would be "They are the actual average crown angles."

 

[adamasgem]

Date: 1/26/2007 5:27:56 PM
Author: Rhino

Date: 1/26/2007 5:16:33 PM
Author: strmrdr
You know something about my answer bugged me and after thinking about it...

Can average angles of 8 facets ever be considered true or actual?
None of the facets may actualy have that specific number.

Answer: Yes. The proper wording IMO would be 'They are the actual average crown angles.'

It is my understanding that the scanners use the stepped pedestal to calibrate the system.

It might be interesting to check the scanners linear calibration using square steel guage blocks, which can be obtained for $25 bucks or so in 1/4 inch sizes with linear tolerances +/- 0.000005 inches 0r equivilently +/- 0.000125mm

A small right angle optical prism to check angle accuracy or consistency might also prove informative, as one can flip it..

Of course the apriori model the scanner is trying to solve for would have to be changed. I don't know how difficult that would be. Have to check with Sarin on that, or maybe Serg could comment..

PS I would avoid the use of the word "actual" and replace it with "measured"