Appraisers - matching mounted diamond to lab report

[stebbo]

Not talking about verifying the data on the report, just that the report is indeed for this stone, without unmounting.

Can you correlate enough observations and measurements on a mounted diamond to get essentially 100% confidence in a match or mismatch, assuming things like possible inscription tampering and lack of inclusion plot?

 

[Garry H (Cut Nut)]

yes

 

[diagem]

Date: 9/28/2007 12:55:01 AM
Author:stebbo
Not talking about verifying the data on the report, just that the report is indeed for this stone, without unmounting.

Can you correlate enough observations and measurements on a mounted diamond to get essentially 100% confidence in a match or mismatch, assuming things like possible inscription tampering and lack of inclusion plot?

If you are asking Garry this question...., I would agree with him...
BUT, I would not say all "appraisers" would have either knowledge or experience to I.D. mounted Diamonds..., especially rounds....

 

[denverappraiser]

No,

Some reports are shamefully lacking in information and what’s provided is often inaccurate. The clues to matching a stone to a cert are things like the various dimensions, the faceting of the girdle, the fluorescence, the clarity and color, the weight, the girdle inscription, things on the plot, gemprints, photomicrographs, etc. If the data’s all there it’s pretty easy, if some or most is unavailable it’s a matter of accumulating a preponderance of evidence. A fair amount of lab documents contain little more than 3 dimensions, weight, clarity/color guesses and a completely empty plot. At the same time, some mountings prevent you from precisely getting even the basic measurements. These sorts of situations can’t be matched to anything like 100% accuracy. A GIA/AGS report with a mounting that allows reasonable access to inspect the stone is usually pretty easy to match but there are a LOT of very similar stones out there. Even with this, 100% is not a reasonable standard.

So far, counterfeiting a girdle inscription is extremely unusual. Occasionally they get polished off or hidden by the mounting but, although possible, adding a fake to fool people into matching a stone to the wrong report is very unlikely. As laser equipment becomes more common this may become more of an issue but, so far, I don’t recall ever seeing this.

Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Appraisals in Denver

 

[oldminer]

You can see the correct answer is actually "Yes" and also "No". It depends on many circumstances and it would be simply dangerous to make a blanket statement that a qualified expert can relate every mounted diamond, with 100% accuracy, to a certain report. If there is a measureable or visual difference, then the answer is yes, but if the difference is slight enough to escape detection while mounted, the answer is no.

What degree of certainty is required by most consumers? Most want assurance that their fine diamond has not been switch for a poor diamond. There is no financial benefit to switch one fine diamond with another fine one. If you are going to be a criminal the mentality is usually that you won''t get caught so just go for the maximum benefit.

When we are asked to laser engrave a document number on a diamond, we insist on seeing the ORIGINAL lab report which goes with the diamond. We check the weight, basic measurements, color,,clarity and match the plot before we engrave to prevent fraud on consumers and other dealers. We don''t charge extra for this, but do it because we feel it is essential.

 

[Richard Sherwood]

It depends on how much wine I''ve had.

After a bottle, I get exceptionally good at matching certs to stones. Hell, after two I can even match up EGL-Israel certs to stones.

 

[stebbo]

Date: 9/28/2007 7:03:52 PM
Author: Richard Sherwood
It depends on how much wine I''ve had.

After a bottle, I get exceptionally good at matching certs to stones. Hell, after two I can even match up EGL-Israel certs to stones.

Alcohol also makes diamonds appear better?

Thanks for the insight guys...

 

[Garry H (Cut Nut)]

Date: 9/28/2007 7:31:57 AM
Author: denverappraiser
No,

Some reports are shamefully lacking in information and what’s provided is often inaccurate. The clues to matching a stone to a cert are things like the various dimensions, the faceting of the girdle, the fluorescence, the clarity and color, the weight, the girdle inscription, things on the plot, gemprints, photomicrographs, etc. If the data’s all there it’s pretty easy, if some or most is unavailable it’s a matter of accumulating a preponderance of evidence. A fair amount of lab documents contain little more than 3 dimensions, weight, clarity/color guesses and a completely empty plot. At the same time, some mountings prevent you from precisely getting even the basic measurements. These sorts of situations can’t be matched to anything like 100% accuracy. A GIA/AGS report with a mounting that allows reasonable access to inspect the stone is usually pretty easy to match but there are a LOT of very similar stones out there. Even with this, 100% is not a reasonable standard.

So far, counterfeiting a girdle inscription is extremely unusual. Occasionally they get polished off or hidden by the mounting but, although possible, adding a fake to fool people into matching a stone to the wrong report is very unlikely. As laser equipment becomes more common this may become more of an issue but, so far, I don’t recall ever seeing this.

Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Appraisals in Denver

All good points Neil, but in such lousy report cases - matching it is a waste of time.

In the case of Stebbo''s question - the answer becomes:

Bin the report and provide the client your own.

 

[Garry H (Cut Nut)]

Date: 9/28/2007 9:42:21 PM
Author: stebbo

Date: 9/28/2007 7:03:52 PM
Author: Richard Sherwood
It depends on how much wine I''ve had.

After a bottle, I get exceptionally good at matching certs to stones. Hell, after two I can even match up EGL-Israel certs to stones.

Alcohol also makes diamonds appear better?

Thanks for the insight guys...

Alcohol can also be a substitue for a man needing a women, and so all the diamond budget can go on wine.
(but then the women whine, which becomes wine, women and sort of song)

 

[denverappraiser]

‘Certificate matching’ is a service that gets asked regularly of both appraisers and jewelers. The general idea is that if a stone is ‘certified’, all that’s necessary to know if it’s priced appropriately is to understand that it’s the same stone as what’s described on the the report. I finally stopped offering this service for consumers because inevitably people want to know far more. They want to know if the grading is accurate to GIA standards (which means I have to grade the stone), they want to know if there are other attributes that they should be considering in assessing the merits of the stone (which involves doing more a more in depth inspection as well as providing an explanation) and they want to know if their price is right (which involves research and another explanation). In the end, what they want is a full appraisal and they’re just hoping that this will lower the price.

Matching a stone to a lab report provided by a dealer is often a very useful step and I do it whenever possible as part of the appraisal process for a variety of reasons. For example, usually the labs will get the weight right, which means that if the stone can be matched to the report, the report becomes good evidence about the weight without pulling and resetting the stone which can damage the stone, the mounting or both. The lab report is often the link between the stone and the invoice and this can be a big deal if the client feels that the selling jeweler has misrepresented something or that the stone may have been switched since the original sale was made, both of which are among the reasons that people seek out independent appraisals in the first place.

Matching on unmounted stones is a service I often offer to my dealer clients. Most dealers are fairly accustomed to sending out one or more stones for inspection that are then returned unsold for whatever reason. It’s not so unusual for a store to order in several stones from different sources and it’s easy for them to accidentally ‘shuffle the deck’ before returning them. Mistakes happen. Obviously it’s important to correctly match stones and reports before they go back into inventory and it can be helpful to have a separate set of eyes assist even though they have no interest at all in my opinion about the accuracy of the grades or the attractiveness of pricing.

Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Appraisals in Denver


Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Appraisals in Denver

 

[Richard Sherwood]

I quit "certificate matching" as well. That''s never all the client wants to know. They usually want the whole magilla.

So now I just do the whole magilla up front, which answers all their questions and compensates me for my time.

 

[elmo]

Exactly, the question I ask as a buyer is not just "is this the stone in the report", but how would you grade this when taking the time to do it fairly meticulously, not grading on a GIA assembly line, working with me and not the seller. Then talking with me about things that aren't on the report for 20-30 minutes.

 

[Modified Brilliant]

I like the challenge of doing my own work first..then comparing my findings with GIA or AGS.
If an appraiser has confidence in his/her abilities then this is the best route to take.
If my findings are slightly different, then an explanation is forthcoming.

I love Q & A sessions.
It''s your time and money to use the appraisal session as you see fit.

Jeff Averbook, G.G. Graduate Gemologist/Appraiser

www.metrojewelryappraisers.com