Four Questions about Diamond Databases, and the interpretations of cut they afford...

[Regular Guy]

Dear Friends,

Thanks for helping me understand the databases that make this world go round...

1) Regarding the big database, that is referenced at Dirt Cheap Diamonds and Abazias and White Flash, and by many of the internet vendors who we do have reference to, that includes 50 - 60,000 diamonds ...

a) who populates the data in the databases, gets diamonds into their inventory, and sets prices in them
b) is it clear that among the categories that are included in this big database, different grading categories are available to populate as well, and as a result, when White Flash and DCD has diamonds listed respectively as:

White Flash:

A) Ideal H&A
B) Ideal
C) Very Good
D) Good

Dirt Cheap Diamonds

B) Ideal
C) Premium
D) Average

...they are merely porting over data...whole...with very little manipulation of the information, just bringing over the categories as they find them populated originally.
c) Importantly, what criteria are used to differentiate these grading categories?
d) Although all vendors may be able to access the entire database, do some of them only advertise selectively from them, such that -- for example -- when the diamonds are visible on both the vendor''s databases, as well as Pricescope''s database, why are only even a couple of duplications noted, instead of multiple duplications, represented by each of the participating vendors?

2) Regarding the database of databases, recorded on the Pricescope website itself, it would seem that the data brought over from these distinct databases is massaged as well, although I assume these grading categories are dropped out
a) But, Pricescope then seems to implement it''s own system to massage data and create grading categories; is that right...
b) as for example, it appears that if the user was merely trying to differentiate those diamonds that were categorized as "AGS0," they would check the box at the top left. And that when doing so, the only screening of information that occurs (is this correct?) to differentiate these diamonds is the changing of percentages for both depth and table:

- Without seeking those diamonds specified as AGS0: Table 53 - 62, Depth 58 - 63
- Narrowing to only those that are AGS0, Table 53 - 58, Depth, 58.7 - 62.3

c) and relatedly, it is also likely that, for even those diamonds that appear in the table to begin with, both good/average diamonds may be screened out at the outset, based on the recording of depth and table data.
d) alternately, when H&A is checked, no additional screening of the data presented seems to occur.

3) Just how meaningful is depth and table data? It seems clear that as a validating measure, it is widely enough used, such that it is the only data one can reliably expect to come over and be reported on, from any and all of these databases, including Pricescope''s data.
a) can perhaps a majority of the story about a diamond''s cut be validated by this info, broadly?
b) Specifically, what validity should be given (as some of these databases seem to imply by their inclusion of this data alone) to the idea that is presented, in a plain spoken manner, and seen at Tradeshop.com:

"Various cutters have slightly varied definitions of the ideal cut, but if you keep the table size in the mid-fifties and depth between 58-63% you will have a fantastic diamond, and look...."

4) OK, I''m also interested in both seeing whether a strategy can be implemented to exploit the data to ones personal gain, and also, to explain the (relatively accidental) success I seem to have had in finding the diamond I purchased last month.
1) Regarding my diamond, I was attracted to it from DCD''s website, and presentation on it''s database, because of it''s basic characteristics: weight, color (G), clarity (VS2), and although I may have given passing notice to its depth, table, and culet measurements (62, 55, 0), it had been grouped among those diamonds that were classified as "ideal." both at the DCD site, and also on Pricescope''s database
2) But, when we did get the diamond "in-house," it could be seen because of the crown and pavilion angles (35.8, 40.1), it would otherwise be "classified" as an AGS2 stone, and likewise, it has been appraised accordingly.
3) Also, regarding the diamond''s pricing, to all appearances, it''s pricing had put it among those diamonds that were not specifically ideal (.9 carats, $3316). Jim Schultz had said it was just "well priced," but I had to wonder what process must have been used to set the price, after which it was placed into the larger "database," and made available to DCD and me.
4) Although I thought it might have strategically been placed among the "ideal" category, based on someone understanding it''s excellent cut (HCA = .9), I think it more likely that it was either mis-categorized, or more probably, categorized as ideal simply because of its table and depth measurements, at the outset, but I can only speculate. At least, I can only speculate, until I hear from you(!)

So, there''s a lot here, the last of which is personal, but most of which is quite general. For anyone in or out of the trade who would like to comment -- your feedback is appreciated.

Thanks!

 

[oldminer]

Ira;

You sure don't ask questions like your nickname, "Regular Guy". I wish I could find adequate time to address the portions of your questions that I might even have a partial answer to. You have some truly insightful questions, but ones which few of us have expertise to share with you.....

I think pricescope does a great job with pricing diamonds and with standard knowledge, but you have picked some far more advanced topics about which few could assist you. It isn't for lack of wanting to help, but just lack of people able to go to your level.....

I sure hope you have found a great diamond besides someone who can share your curiousity and intelligence, as well.

 

[Regular Guy]

Dear David,

You're sweet (I think!) to compliment the questions. And yes, I am very fortunate on both of the points you mention -- in having a wonderful spouse, and also, in having found a ring that she seems to appreciate quite a lot.

But, c'mon. I AM a regular guy! I just write long. But many of the very regular people who write and read here must have similar questions. The answers to the questions represent the foundations upon which Pricescope works.

My guess. Re questions #1 & #2, any interested vendor should be able to address the first one, and re #2, Leonid or anyone who is simply engineering this site should be able to review this one as well.

You could conjecture with some aplomb about #3, I'll bet.

But, yes, who has time. Frankly, I'm trying to get out of the business of making time for this, and hope that will be done by week's end, or earlier. Thankfully, professionals such as yourself make time with some frequency to attend to this site as often as you do, and we are grateful benefactors of this.

But, as one who has seen how the grading classification you have created of "1A" hits the sweet spot within AGS0, surely you can speak in a "waving your hand sort of way" to the relative relevance of this for the "regular guy" shopper, and the consequences of shopping for it, or not.

But I'll not twist your arm. Thanks already for writing back!

With sincere respect,

 

[valeria101]

Not in the trade, so .... I would not venture with my 0.2, but you may guess I gave these a thought before.

To me this open databases make a great environemnt for nudging consensus both among quality categories and pricing across the board (literally, since the content of databases starts from cutters and gets client exposure). If you do find lots and lots of time to dig into the recent history of the ideal cut and PS's posts to conclude how the expectations about diamond quality evolved, maybe you would agree. There is some pretty well established theory backing such observations as well.

Would it be possible to sum up your questions in just one? It is a bit difficult for me to catch up the main issue under your questions (beyond the hasty guess above)...

 

[Regular Guy]

I suppose the singular question could be:

How can one take best advantage of the resources of Pricescope to make a diamond purchase, finding a diamond at the intersection of price and quality, that will do justice to our sweetheart -- based on whatever budget we happen to have?

The individuated questions here are just designed to pick out the details associated with getting at the answer. You know what they say….the devil’s in the details (so scroll up to the first entry for items 1 – 4)

Sounds pretty much like a regular guy kind of question to me!

Thanks for your interest.

 

[pricescope]

RG,

1.a. Some of these listings are they own inventories and others are populated automatically using available sources in the trade such as wholesalers’ databases or different B2B trading networks. Note that there are much more diamonds in the trading networks that is currently listed in the internet. Many wholesalers do not want their diamonds to show up in the web which might irritate their retail customers.

1.b&c. My guess: it is done automatically to simplify filtering diamonds based on available data such as table, depth girdle, etc. In this case vendors can have their own filtering criteria e.g. diamond with 63% depth or thick girdle cannot be in Very Good cut grade. It can be helpful if you don’t want to consider nothing less than (e.g.) very good numbers. Then you still have to check each diamond separately because these grades are rather for preliminary automatic filtering than a guarantee of quality.

1.d. Not always. Sometimes certain vendors prefer to work with certain suppliers and vice versa. However, there are still plenty of duplicate listings out there.

2. All the numbers/data that can be retrieved from vendors' websites or databases are included into PS database. Home-made cut grades are not used because they can be different e.g. Blue Nile, DCD, WF, Mondera.

2.a. I do not use any in-house system but merely filter diamonds for the stats based on the AGA classes. However, there might be mistakes because majority of the diamond listings do not have crown and pavilion data.

2.b. When one searches for diamonds with AGS0 option on, only diamonds with AGS0 report or with AGS0 or Sarin0 in the comments should come up. I only try to make sure that there are no mistakes and diamonds with say 60% table won't show up.

2.d. When you select H&A, there should be only diamonds that are AGS0 (see 2.b above) and also commented as H&A.

3. Table and depth number should be considered in accord with other parameters but sometimes you can say the table is too large or depth is too deep or shallow and filter such diamonds out.

3.a. I'm afraid, no. Diamond cut issue is going far beyond just numbers even if all of them are known. Sometimes you can say the diamond with this parameters should be a nice stone or definite reject. However you cannot say I like this one more than another.

3.b. Based on this statement you can buy a nice diamond but you also might buy a bad one. It is about the same as saying buy 60/60. For example, there is high risk to get not-so-good stone with 58% table and 63% depth. Both of these parameters are connected and one should know at least crown and pavilion angles for round diamond. For fancy shaped diamonds even crown and pavilion will not be enough.

4.2. You've got a great stone not because table and depth but because crown and pavilion angle relationship was right (HCA=0.9).

4.3. there are many factors in "pricing" the diamonds - cut quality is only one of them.

4.4. I'm speculating too but I think it was placed into ideal category only because of its table and depth numbers and you were lucky to get also nice combination of crown and pavilion angles.

Don't worry about current AGS2. Hopefully, next year GIA and AGS will come up with new cut grading system and your diamond will be graded/cost much higher.

 

[oldminer]

You're right. #3 is okay for me.

Quote:
"3) Just how meaningful is depth and table data? It seems clear that as a validating measure, it is widely enough used, such that it is the only data one can reliably expect to come over and be reported on, from any and all of these databases, including Pricescope's data."

REPLY:
Depth and table data BEGINS to tell the story of the craftmanship in the diamond. You can have ugly diamonds with perfect table or depth measurements, however. So it is insufficient to make a decision only on this criteria. However, it is very unlikely to find a wonderful diamond outside of the recommended ranges, too. Diamonds that just happen to look great when outside the fine cut range usually have serious durability or small appearance for their carat weight issues. Other things such as the right depth and table combined with a super heavy or super thin girdle obviously are problematic.....

Quote:
"a) can perhaps a majority of the story about a diamond's cut be validated by this info, broadly?"

REPLY:
Unfortunately, NO. Many sellers would love you to think so and I don't blame them for hoping to save their time and effort, but it isn't possible to do it this way and reveal the whole story. It is a good way to conceal problems.

Quote:
"b) Specifically, what validity should be given (as some of these databases seem to imply by their inclusion of this data alone) to the idea that is presented, in a plain spoken manner, and seen at Tradeshop.com:"
"Various cutters have slightly varied definitions of the ideal cut, but if you keep the table size in the mid-fifties and depth between 58-63% you will have a fantastic diamond, and look....""

REPLY:
Tradeshop is a good site. They do use plain language and most all of it is going to steer people correctly. I think buying a diamond outside of their recommended parameters is likely to make the purchase dangerous. Again, not every single diamond within these parameters is a superb stone. Not every AGS 0 cut diamond is equal to another. The variation from one AGS 0 to another AGS 0 can be quite surprisingly wide. AGS 0 incorporates some weakish parameters within the 0 cut grade....Maybe they will improve upon this in the future. An AGA 1A has no weak zones, but is harder to find.

Another thing to consider is so many GIA graded diamonds are available and only come without a lot of the important data. Do we want to disregard these stones? Some of them could be very good stones to buy. Dealers must advocate consideration of GIA graded diamonds in order to make their necessary sales. I am not against that, but one must then rely on the seller to look at the diamond and tell them it is a fine example, and not a poor looking one. Even an added Sarin or Ogi report does not define light behavior.

In the end, Tradeshop and many other sellers are saying to consumers, "Look, we have examined this diamond. It has important characteristics that are on target AND we tell you it looks fantastic." Trust is the issue, not parameters. If a respected dealer promises you a diamond that has excellent parameters AND excellent light return, then a consumer may say, "Fine, show me the diamond." "I'll take a look."

I think this is the way to play this out. One can't make blanket assessment of light performance based on a couple parameters when having every parameter still won't quite do the whole job. Even ray tracing has problems and faults. One must have light behavior data or have an expert look at the stone. Nothing else could be so complete.

Hope this answers the question.

 

[Regular Guy]

Here’s to a couple of hard working blokes, the likes of which I could have barely hoped to see.

I’d like to raise a virtual beer to you both.

And, since I have to think my specific note caused your reply, it is my greatest hope that others will benefit from your hard work, as well.

Sincerely,