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joxxxelyn

Shiny_Rock
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Jan 14, 2010
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Does anyone know why a diamond listed on GOG would have different proportions listed for the table on the AGS report vs. the info GOG itself lists for the diamond? I thought it was a mistake but it turns out that even when the tables of August Vintage rounds are around 47, the info for the diamond lists them as closer to 50. Here''s an example of what I mean: http://www.goodoldgold.com/diamond/6928/ and http://www.goodoldgold.com/diamond/6808/

Where other diamonds actually measure out the same as the report, they do match. Also, the crown and pavilion are always listed the same: 34.5 and 40.75. It seems like they are "rounding" the proportions on the diamond''s info closer to the ideal side.

I already asked them about this a week ago and am still waiting. I was wondering: which measurements are more reliable?
 
Very odd. But, really, whatever the numbers are, they aren't very important. What's more important is the pictures. I mean, looking at it, yes, I can see that it's a very small table, 50% or under, but I don't really worry about what that number is exactly once I have pictures in front of me.
 
Jonathan posted the following on another thread. It provides an explanation of the differences.


Date: 2/3/2010 10:33:01 AM
Author: Rhino
Hi reggie,

Caught your posting here and would like to clarify. GIA, AGS and our lab each use what is perhaps the most sophisticated Sarin measuring device on the market to arrive at our proportions. A Sarin machine is a non contact measuring device that measures each facet of the diamond and while each of our machines are calibrated properly, these machines do have a certain amount of tolerance from machine to machine. If you note the comparisons you list below (except for the crown angle) are within .0x or .1% of each other. This is actually pretty amazing consistency. One extra machine we possess is a Helium scanner which is arguably even better than the Sarin and is what we generally use to generate our Gem Advisor files with.


Concerning the biggest discrepancy (the crown angle measurement) there is a default set of angles that get loaded on our website when no angles are provided being 34.5 crown and 40.75 pavilion. A problem we are having taken care of.


Thanks for asking and for considering us reggie. If you''d like you can learn more about the Sarin and the Helium scanners here.


Jonathan

 
joxxxelyn – Good question as I noticed the same thing when I was getting ready to buy a av cushion. I agree that it seems a little suspect that the numbers aren't universally accurately. I find it interesting that both the av cushion and av round are having these issues.

If you find out the answer please tell us all as I’m sure we aren’t the only two who have ever had these questions before. I would give them a call instead of waiting for an email reply. I found that everyone I talked too seemed a 100 times more helpful on the phone. Maybe they think you are more of a serious buyer when you are willing to pick up the phone and so they go the extra mile for you. For example, when I asked them for a video of a few diamonds by email they didn’t want to do it unless I came up with a good enough reason (they said pictures could answer all of my questions instead). When I talked to them on the phone they volunteered to do it without me even asking.

Regarding my situation and after reading your post I think to myself why didn’t I ask them about these discrepancies when I was on the phone with them. Not to make an excuse for them but I determined (as far as av cushions go) that it didn’t matter what the number said as I’m still going to buy the diamond if the video and pictures all look good. I think I would have probably bought something if it had any numbers really.

When purchasing a round the basic stats do seem to hold a higher value when evaluating a purchase. It seems all the proportions and angles have ideal ratios and any deviations from that should at least make you pause until you can get more information. Fortunately GOG and some other vendors do provide you with extra information but you still have to know how to interpret them.

To me it’s clear something is really wrong with their accuracy between the lab report and their own av numbers. When looking at the second diamond you posted the table % is off by 2.71%. The table % was off by 1.22% for the av cushion I was looking at. As a company who utilizes the internet for sales you would think accuracy of everything should be a given otherwise a potential customer might decide to pass on this vendor and go with another. I think this is especially true when the potential customer is in the initial phase of a purchase and is in the process of trying to gather information from different sources. BTW, I ended up buying their av cushion h vs2 that was mentioned on this thread.

Good luck and I’m sure the answer to your question isn’t as sinister as we might initially assume.
 
Date: 2/6/2010 10:21:45 PM
Author:joxxxelyn


I already asked them about this a week ago and am still waiting. I was wondering: which measurements are more reliable?
I always go with the AGS or GIA reports for the measuremens. But heck.. sometimes vendors even attach the wrong report or have the wrong price.
 
GOG is doing nothing wrong.
I worked in engineering, taking and analyzing data, for 23 years and measuring anything precisely is not easy.
Dealing with people looking at data is not easy.

Data always have some number of figures.
This number has 5 figures: 64.748.
This number has 3 figures: 64.7.

Everyone wants more and more figures, so they spend lots of money buying equipment that can report more figures.
Everyone splits hairs.
But the truth is you cannot always believe the last figures that any test instrument gives you.
The experienced people know this but when there is pressure to achieve a certain number the there is financial pressure to believe every digit the instrument gives you.

A multimillion-dollar contract may depend on one spec being 2.45.
If it is only 2.42 your company does not get the contract.

Even the finest test equipment, by Hewlett Packard, was not perfectly repeatable.
We had identical test benches, each valued at over a quarter of a million dollars, all freshly calibrated by the same person.
We'd measure the same item on all 5 benches and get slightly different numbers.
Then if you did the same test the next day the same bench of equipment would not give you the exact same number it gave you yesterday.
This drove the managers and program directors crazy.
In the end we learned to be very pleased if data varied by less than 10%.

When third parties are checking data they love to nitpick those last figures not repeating precisely.
Unfortunately they do not know, or accept, that the variation is the result of what we call the noise of measurement accuracy.

The expectation of perfection is not realistic.
You should be skeptical of the last digit that any test equipment gives you.
Example: The equipment reads 64.748, so I should really write down 64.75.
I have much more confidence in 64.75 than I do that it was actually 64.748.

If I want to have 5 figures that are believable I should spend another hundred thousand dollars and buy test equipment that reports SIX figures.
Then I'd throw out the last one and report 5.

I'll let Rhino address the specific example above but the principles of measurement accuracy I have outlined here applies to everything that is measured.
 
The AGS/GIA specs are what set the price and cut grade and what will matter in the long run for replacement value of the diamond. Most vendors do not even perform their own sarin analysis and atempt to give their own reports. The fact that GOG and some other companies do this is an added value. The fact that these numbers vary slightly from the GIA/AGS reports in immaterial because GOG''s numbers do no supercede AGS/GIA numbers anyways! Even if they are "skewed" in the direction of ideal, it doesn''t matter. Only the cert numbers matter.
 
As far as being a customer, I already am one. They also have always written me back via email, before during and after my purchase- until now.

I also am not usually one to split hairs, especially to three places after a decimal place. However, when you notice trends in the data of a certain type of data being off a few places in the tens (47 vs. 49), I think it is different than splitting hairs over decimal places, which is something I would never do. Now, these variations in being off to the tens are especially curious given that the ONLY variations are on stones with smaller tables. When GOG measures a table closer to 50, and it matches AGS or GIA, that''s what they put in their diamond''s info as well. If this is really a matter of accuracy, then wouldn''t all tables stand an equal statistical chance of being off somewhere in the tens?? Also, all of the other measurements match more closely, so these variations are outliers with high z scores (if you took statistics). So, while I do not think they are doing anything wrong, I think I may have noticed something that could be significant, which is why I asked. But I will adhere to the reports from now on.
 
Greetings,

Hope everyone is having a good superbowl weekend.
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Thanks for the questions.

As Karl pointed out, and to reiterate these measuring devices have their limiatations as does any technology. If the information is confusing you perhaps it is best that we not publish it to avoid the confusion. Numbers, while genearlly good to know do not tell the story like ASET/DiamXray and optical exams performed on the diamond. Although we have invested in the finest equipment available on the market to measure and scan diamonds, on these particular diamonds it's not good enough and my apologies for any confusion.

As noted in my previous post if information is not loaded on a diamond there is a default set of numbers 34.5/40.75 that are loaded in the system. Please forgive as this is not done to mislead or dont out of maliscious intent to confuse or make a person to think a diamond is better than it actually is. We purposely do not load detailed numerical information on August Vintage diamonds (cushion or round) as well as Octavia so you will generally see the 34.5/40.75 on these diamonds until we get the system fixed.

Hi Joxxeclyn,

This past week we were short a key staff member who was on vacation so my apologies of there has been any delay in email. If for any reason you are not getting an email back as quickly as you'd like call us and we'll take care of any questions/concerns immediately.

Hi Reggie and thank you for everything. Just wanted to address your concern with the video of the cushions and our response via email vs phone. We get numerous requests to shoot videos of diamonds that have already been shot already and we have to be careful how we allot our time as that is a very time consuming process to perform. Particularly if the comparison is one that has been shot multiple times that we can link a client to. Ie. If a person wants to see a comparison of August Vintage Cushions that all look identical and there is no difference from diamond to diamond, we have many videos that show this already. The beautiful thing about a quality brand is that there will be consistency from diamond to diamond. If it is 2 different looking cushions (or any other shape) we are happy to shoot as that will be a new & different comparison and not one that has been shot already many times over.

Hope that helps.

Kind regards,
 
I have an engineering background so I am all about numbers and stats but frankly I am a little baffled with these recent concerns. I agree that the numbers should be accurate and "default" numbers should not be included. But to imply that we are being deceived seem very off base - GOG includes all the reports there for you to access so they are hiding nothing at all.
 
Date: 2/7/2010 11:29:36 PM
Author: CharmyPoo
I have an engineering background so I am all about numbers and stats but frankly I am a little baffled with these recent concerns. I agree that the numbers should be accurate and ''default'' numbers should not be included. But to imply that we are being deceived seem very off base - GOG includes all the reports there for you to access so they are hiding nothing at all.
I agree. True obfuscation would be posting their own results and leaving the GIA/AGS information off the site or something to that effect. I don''t see how there is anything to gain (in the malicious sense) by skewing their own data yet posting the GIA/AGS data as well.

Rhino I am not sure adding the sarin information adds much, personally, to any of the online vendors information. I suppose it adds "completeness" to the vendors assessment of the diamond, but as it is redundant with the GIA/AGS information at best and confusing/contradictory at worst, I don''t see the benefit.
 
Thank you Rhino. That is what I figured. I just wanted to make sure. Again, I want to stress that I do not think GOG did anything wrong, or I would not have purchased from them. As a business it is hard to worry about certain details when you have more pressing efficiencies to consider, like simply processing and uploading all the diamonds and their information. That is a tremendous undertaking and I know GOG stays busy. However, I simply felt that the two figures were competing, and I wondered about the measurement methods due to the differences. As a consumer, I was confused. Dare I suggest that, since consumers use those measurements for things like the cut advisor, that it is made somewhat more clear that there could be variations which affect the HCA score. I don''t think that is very unreasonable, even if it it is just done for standard round brilliant cuts.

And yes, I agree with Reggie, I ultimately purchased because GOG was willing to make videos, scans, and performance indicators for the stones. (That, plus the groundbreaking innovations in cut, make it impossible to pass up.)
 
Thanks for thei input dreamer. Am taking it into consideration. We actually did pull Helium Reports on modified rounds because our scanners have trouble resolving all the facets and was reporting inaccurate data which was confusing folks. I''m not opposed to this idea either.

One correction in my last post ... the poster was not Karl but Kenny. Sorry about that.
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Hi joxx,

Thanks for your response. Thoughts below.


Thank you Rhino. That is what I figured. I just wanted to make sure.
No prob and glad you asked and am happy to oblige.


Again, I want to stress that I do not think GOG did anything wrong, or I would not have purchased from them. As a business it is hard to worry about certain details when you have more pressing efficiencies to consider, like simply processing and uploading all the diamonds and their information. That is a tremendous undertaking and I know GOG stays busy. However, I simply felt that the two figures were competing, and I wondered about the measurement methods due to the differences. As a consumer, I was confused. Dare I suggest that, since consumers use those measurements for things like the cut advisor, that it is made somewhat more clear that there could be variations which affect the HCA score. I don''t think that is very unreasonable, even if it it is just done for standard round brilliant cuts.
I think the value in our Reports (and particularly Helium Reports) are a good value add especially with GIA diamonds which only give the rounded information. At the same time, if one is to consult the HCA on the results of a diamond, that a consumer gain a proper understanding of the tools strengths as well as its limitations. Most of our diamonds score just fine on the HCA but there are round brilliant cuts as well as new round diamonds we feature that score >2 on the HCA yet will be some of the most visually stunning diamonds one will lay eyes on (our new August Vintage Rounds for example). Our first prototypes were cut to get great HCA scores yet suffered miserably in real world observation. I have an article on the subject I''ve authored here in case you haven''t read it.


And yes, I agree with Reggie, I ultimately purchased because GOG was willing to make videos, scans, and performance indicators for the stones. (That, plus the groundbreaking innovations in cut, make it impossible to pass up.)
And I thank you for your patience and patronage as we do our best to serve. Later this year we hope to release some more new ground breaking things.
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Kindest regards,
Jonathan
 
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