whys is this so "cheap"?

[Sharon101]

Date: 5/26/2008 11:31:45 PM
Author: addiction

Date: 5/26/2008 11:14:57 PM
Author: Sharon101
No offence but you are trying to be too clever. The info is even more in shades of grey than you realise. You are trying to be an appraiser or do the job of someone who had to work and study for years to know how to factor in the variables. Your model will be flawed for reasons you are not aware of. eg the price is not just from the individual variables, but from the unique combination of certain variables. eg. rough example....in a perfect diamond over say 2 carats the color `D` will add more to the cost than the color `D` will to a flawed diamond under .5 carats. So sometimes the unique and rare combination adds more value than each attribute in its own right. Anyway, its complicated....thats all I know!!!

Sharon, I appreciate your feedback. The relation you described could be incorporated into the model. Unfortunately, I have enough stats skills to know it''s possible, but it''s been a while since grad school or using Matlab.... maybe there is a stats expert lurking around this forum that would be willing to take on a challenge....

Where there is a will, there is a way....


edit: I know.... I should get my brother to help me out with this, he used to teach stats at SU...

the only problem is no one knows I''m looking for a diamond...

In `theory` I guess anything is possible. Doesnt mean it will work in reality!!!! I also know about stats, but you are not going to really achieve much in my opinion. Acheive meaning to get any tangible results. Also whats your time worth!!!!

 

[arjunajane]

Date: 5/27/2008 4:05:39 AM
Author: Sharon101

Date: 5/26/2008 11:31:45 PM
Author: addiction

Date: 5/26/2008 11:14:57 PM
Author: Sharon101
No offence but you are trying to be too clever. The info is even more in shades of grey than you realise. You are trying to be an appraiser or do the job of someone who had to work and study for years to know how to factor in the variables. Your model will be flawed for reasons you are not aware of. eg the price is not just from the individual variables, but from the unique combination of certain variables. eg. rough example....in a perfect diamond over say 2 carats the color `D` will add more to the cost than the color `D` will to a flawed diamond under .5 carats. So sometimes the unique and rare combination adds more value than each attribute in its own right. Anyway, its complicated....thats all I know!!!

Sharon, I appreciate your feedback. The relation you described could be incorporated into the model. Unfortunately, I have enough stats skills to know it''s possible, but it''s been a while since grad school or using Matlab.... maybe there is a stats expert lurking around this forum that would be willing to take on a challenge....

Where there is a will, there is a way....


edit: I know.... I should get my brother to help me out with this, he used to teach stats at SU...

the only problem is no one knows I''m looking for a diamond...

In `theory` I guess anything is possible. Doesnt mean it will work in reality!!!! I also know about stats, but you are not going to really achieve much in my opinion. Acheive meaning to get any tangible results. Also whats your time worth!!!!

Ditto sharon, sorry don''t get it!
Just put the effort into educating yourself on how to buy the nicest possible diamond for your price range - If you present a beautiful well cut diamond, trust me, no girl is gonna care if you "cracked the code" while buying it!!

 

[addiction]

not all people are the same, just like no 2 diamonds are the same... some "enjoy" (don''t mind) stats or exact sciences and have intellectual curiosity (not saying that others don''t). While educating myself through info from this and other sources in what determines the price of diamonds, I started to wonder if prices shouldn''t be similar for similar diamonds. Looks like cut is by far the hardest to value, as most people have rough estimates for the rest of the C''s, but since I saw HCA and Tolkowsky''s calcualtions, I thought we could grade cut and price it.

 

[arjunajane]

Date: 5/27/2008 9:18:45 AM
Author: addiction
not all people are the same, just like no 2 diamonds are the same... some ''enjoy'' (don''t mind) stats or exact sciences and have intellectual curiosity (not saying that others don''t). While educating myself through info from this and other sources in what determines the price of diamonds, I started to wonder if prices shouldn''t be similar for similar diamonds. Looks like cut is by far the hardest to value, as most people have rough estimates for the rest of the C''s, but since I saw HCA and Tolkowsky''s calcualtions, I thought we could grade cut and price it.

Addiction, to each his own, I was just presenting mho..

 

[Sharon101]

Date: 5/27/2008 9:18:45 AM
Author: addiction
not all people are the same, just like no 2 diamonds are the same... some ''enjoy'' (don''t mind) stats or exact sciences and have intellectual curiosity (not saying that others don''t). While educating myself through info from this and other sources in what determines the price of diamonds, I started to wonder if prices shouldn''t be similar for similar diamonds. Looks like cut is by far the hardest to value, as most people have rough estimates for the rest of the C''s, but since I saw HCA and Tolkowsky''s calcualtions, I thought we could grade cut and price it.

I understand where you are coming from. I get `addictions` or obbsessions as I like to call them too. I can sometimes get very deep into researching my obsession. (Like when I wanted a girl....LOL.....but thats a diff. story). In life its nice to believe we can master things, or have a sense of control or of a level playing field.

Good luck, cant wait to see what you come up with. I really believe you are looking for the needle in the haystack here, but we all have to learn our own lessons. One of the things I am known as is being a realist. I personally think, realistically you cant build a model on so many variables. I think the info will be flawed and the model will be flawed. As a consequence the project will be useless because stats are easily misleading....you know...lies, lies and more lies. And even if you crack the code....prices might change the next minute anyway....or the diamond you want might not be available. Dont forget you have to factor in supply and demand too!!!!!

Im sure you will have fun which is probably what you are trying to do anyway. You want the satisfaction of gaining knowledge which is always a good thing!

 

[canuk-gal]

Date: 5/26/2008 2:28:57 PM
Author: neatfreak
If you just tell us what you want and your budget we can help you get the best bang for your buck, no regression model needed.

HI:

I thought the same at first, but I think it is just "the doctor ordered". Knock yourself out addicition! (you might even find a sample stats package on the interweb to help....

)

cheers--Sharon

 

[addiction]

Date: 5/27/2008 9:26:49 AM
Author: arjunajane

Date: 5/27/2008 9:18:45 AM

Author: addiction

not all people are the same, just like no 2 diamonds are the same... some 'enjoy' (don't mind) stats or exact sciences and have intellectual curiosity (not saying that others don't). While educating myself through info from this and other sources in what determines the price of diamonds, I started to wonder if prices shouldn't be similar for similar diamonds. Looks like cut is by far the hardest to value, as most people have rough estimates for the rest of the C's, but since I saw HCA and Tolkowsky's calcualtions, I thought we could grade cut and price it.

Addiction, to each his own, I was just presenting mho..

Jane, no pun intended.

I enjoy learning new things and this whole experience proved challenging so far (I still haven't bought anything

). The easy way to figure out if the price quoted by a jeweler is "fair" is to apply a relative comparison method, but that's won't tell you a lot about the intrinsic value. A lot of people have iPhones / BlackBerry now so they can quickly do a search right here on PS on the spot and find some comparisons. I ran the HCA in T&Co and I could see the SA face while it was running... all that anticipation, I don't think he knew what he would say if it came out bad... luckily it came good

Not to digress, but what I'm interested in is to understand how much are all these variables contributing to a diamond's worth (in average)? Is color more important that clarity and priced higher? Is cut a better gauge? Is the symetry all that important? In general, the question is: IS THE PRICE FAIR, based on current market conditions, supply/demand and price-determining characteristics?

 

[arjunajane]

Date: 5/27/2008 9:53:39 AM
Author: addiction

Date: 5/27/2008 9:26:49 AM
Author: arjunajane

Date: 5/27/2008 9:18:45 AM

Author: addiction

not all people are the same, just like no 2 diamonds are the same... some 'enjoy' (don't mind) stats or exact sciences and have intellectual curiosity (not saying that others don't). While educating myself through info from this and other sources in what determines the price of diamonds, I started to wonder if prices shouldn't be similar for similar diamonds. Looks like cut is by far the hardest to value, as most people have rough estimates for the rest of the C's, but since I saw HCA and Tolkowsky's calcualtions, I thought we could grade cut and price it.

Addiction, to each his own, I was just presenting mho..

Jane, no pun intended.

I enjoy learning new things and this whole experience proved challenging so far (I still haven't bought anything

). The easy way to figure out if the price quoted by a jeweler is 'fair' is to apply a relative comparison method, but that's won't tell you a lot about the intrinsic value. A lot of people have iPhones / BlackBerry now so they can quickly do a search right here on PS on the spot and find some comparisons. I ran the HCA in T&Co and I could see the SA face while it was running... all that anticipation, I don't think he knew what he would say if it came out bad... luckily it came good

Not to digress, but what I'm interested in is to understand how much are all these variables contributing to a diamond's worth (in average)? Is color more important that clarity and priced higher? Is cut a better gauge? Is the symetry all that important? In general, the question is: IS THE PRICE FAIR, based on current market conditions, supply/demand and price-determining characteristics?

fair enough - but I think you'll find most people's understanding is that the above (highlighted) are all completely Personal Preference, including price - as in, to some people money isn't an object so the price will always be fair. To the rest of us who are on a budget, the "fairness" of the price will be determined by the extent of that budget..
if you read Shortee78's response in her thread where you posted, she has proven just this - her definition on the "fairness" of price will be dictated by the constraints of her budget..

...and so therefore all these variables will be so very different from one individual to the next. maybe I don't understand as I'm not a "numbers person", but how can you qualify preferences?

Anyway, I'm probably missing the point but hey, like I said before - to each his own! And I agree with Sharon101 - knock yourself out, it will be interesting to see what you come up with!

all the best, AJ.

 

[Dreamer_D]

I totally see you are getting your rocks off doing the stats, more power to you, but your focus is on understanding price and I wonder if your obsession could be turned to aspects of diamond buying that will ultimately be more fruitful, and perhaps, more appeaing to your partner? Lots of guys come on here asking things like, "Is this a good deal?", "Is this a fair price?", "Where can I get the cheapest diamond?" and inevitably they still have so much to learn about cut, labs, color, and all the other variables. Before creating a regression equation to predict price based on all the variables that make a great diamond, why not obsess over understanding what each of the variables really is? I see in your last post you started asking questions about color, cut, clarity etc etc etc. I too am a researcher and understand obsession, but I think maybe point your obsession in a slightly different direction and you may come up with something. Plus, the folks on here seem to enjoy talking about quality more than price, so you may have more fun.

PS: strickly speaking, you may need to include interaction terms in your regresson, such as color x carat, which would address the issue that someone raised earlier about high color D''s being more that lower color Ds. Too complex. You have lots of mental energy, don''t focus on this one thing, harness that power to learn it all!

Just MHO. Enjoy!

 

[JulieN]

Date: 5/27/2008 9:53:39 AM
Author: addiction
I ran the HCA in T&Co and I could see the SA face while it was running... all that anticipation, I don''t think he knew what he would say if it came out bad... luckily it came good

Lol! That is awesome.

 

[whatmeworry]

If you have an intellectual itch to scratch, go for it. Tell us what you discover after you''ve crunched the numbers. I''d be interested to hear what you find out.

 

[denverappraiser]

Addiction,

I know a little bit about statistics too. I'll try to help.

I think you’ve made a critical assumption that deserves rethinking.

Date: 5/26/2008 8:58:12 PM
Author: addiction

I understand that no 2 diamonds are the same, but surely extremely similar gems (4C, angles, %, and the rest) certified by the same lab should cost the same???

The key problem with the alternative labs is not that they use a different grading scale than GIA (although this can be slightly annoying), it’s that they apply the scale inconsistently. You cannot, for example, say that EGL-SI1 = GIA-SI2 or even GIA-I1 and make a conversion chart. Some do, some don’t. You can’t even say that EGL-SI1 = EGL-SI1. Therein lies the difficulty in trying to translate the documents in a useful way. When you write your formula, clarity, color and cutting are all variables, not fixed like you're assuming. Pricing, in general, is based on the actual grade of the stone and this is what you're trying to determine, not the price (which is one of the few pieces of hard data that you actually do have). You need to solve the equation for grade, not price. The correct grade is not necessarily what's on the paper and it includes grading information that often doesn’t even appear. That's what makes the statistics fun. You have to make sure you're asking the right question.

You’ll notice that none of the pros here will give you a price on any stone that they haven’t actually seen. This is the primary reason. It’s easy enough to pull up a list of stones that have superficially similar descriptions and make some statistical averages about those results but you have no way of knowing if the original assumption about grading is false. In fact, one of the best clues you have is the asking price although a close second is the choice of lab. A stone that is priced out of whack with other similar stones in the same marketplace almost certainly has a problem that isn’t obvious from the paperwork.

This also is the reason that advisors here routinely request additional information that isn’t normally provided on the charts. This may be more subtle details from the lab report or it may be photos or the results of other kinds of measurements or tests. The idea is to figure out what is going on. You KNOW there’s an issue here, that’s why you asked the question. A 1.25/H/VS2/Ideal does not go for $5400 from a sensible dealer, and the one you linked to is a sensible dealer. There are several choices but the most obvious is that it’s not accurately graded to GIA standards. The various EGL’s do not use the same definitions of ideal, and GIA doesn’t use the term at all so right off the bat you have a suspicious claim. The dealer drops this term with no explanation at all but what have you really learned by it? What if it’s a GIA-VG, or an AGS-5? Could it be a GIA-I? or a J? GIA-SI1? Who knows but you are surely aware that these details make a huge difference in the price. You’re relying on the dealer for this sort of information and the dealer you’re relying on has never seen it, they’re relying on their supplier. Guess who selected and paid the lab. It’s up to you to decide if this chain of reliance is credible but it’s the reason the price is lower than what you are using as comparable offers from others.

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

 

[addiction]

Neil,

thanks for the very detailed explanations and great point you made. I do have some comments and I would enjoy if you have more time to discuss this further, if it interests you.

First, I still don''t know if you agree with my previous statement:

I understand that no 2 diamonds are the same, but surely extremely similar gems (4C, angles, %, and the rest) certified by the same lab should cost the same???

I understood the point with the discrepancies between various lab grading, which could pose problems in the underlying assumptions about the independent variables, but what about gradings from the same lab?

(...) but you have no way of knowing if the original assumption about grading is false.

I don''t believe I''m qualified to test if the assumptions are true or not. Instead, I''m relying on the professional grading labs to do that for me. Obviously, if you find that a lab consistently grades incorrectly, that makes the data unreliable and would probably be adjusted or excluded.

My point is that one could potentially develop a "complicated" regression model based on market values and draw a fair conclusion on the price of a candidate stone. The model should include detailed data in regards to C''s, angles, depths (similar to HCA). If we come to an agreement as to what makes a stone "appealing" in general (fire, scintillation, etc) and according to HCA and Tolkowsky we can, we would be able to measure that and draw similar conclusions.

I COULDN''T HAVE SAID IT BETTER

From ACS''s website - http://www.americangemsociety.org/jewelrybuying.htm

TAKING THE GUESSWORK OUT OF DIAMOND BUYING.

Most people know little about diamonds. That''s why the American Gem Society came into existence over 70 years ago. Thanks to Society members, we now have precise standards for evaluating diamonds, commonly known as the 4 Cs: Cut, Color, Clarity, and Carat Weight. The American Gem Society Diamond Grading Standards evaluate three of the four value factors — cut, color, and clarity — on its own 0 –10 scale. 0 (Zero) is the highest grade, and 10 is the lowest. AGS "0" indicates an AGS Ideal Cut diamond that has no color and no inclusions or internal characteristics. The three factors are expressed separately along with the fourth factor, the carat weight of the gemstone, for the final American Gem Society Grade.

THE SCIENCE OF DIAMONDS.

While not everyone will share the same opinion as to what constitutes beauty, most people want a diamond that expresses their individual taste and personality. Here’s what you should consider first, however, before buying a diamond:

.......

I can''t say that the value resulting from a model like this will be universally accepted, but it would be very close to the gem''s intrinsic (fair) value based on market values.

I used to works as a real estate appraiser and there are various "complicated" statistical models used to derive fair market values.

I still believe that building such a model for deriving fair market values for diamonds is doable. I might not have the required statistical skills to do it, but it''s worth

a shot.

Dan.

 

[denverappraiser]

Dan,

If the labs were internally consistent and the data were complete it would be easy to do as you suggest. You could simply make a conversion chart and you would be done. To convert this to real estate terms, the problem is that you’re measuring the square footage using a rubber yardstick and rounding the number of bed and bathrooms to the nearest 5. What has the client learned from such an evaluation? It’s not completely useless but a 2200SF, 5 bedroom 5 bath house for ‘only’ $200,000 may be something very very different from what they are expecting. In real estate, the answer would be simple. Fire the appraiser, ignore their report in it’s entirety and hire someone who can both measure and count. For some reason people are hesitant to apply the same logic to diamond appraisers and labs. It’s worth noting that, unlike real estate appraisers, jewelry appraisers and gem labs are completely unregulated in the US.

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

 

[addiction]

Neil,

I do believe the problem comes from the lack of regulation and major self interests of a few "chosen" in the industry. This "magical" air surrounding the diamond industry would be totally demystified if there would be regulation and many "sellers" would be hurt by that.

While I agree with your real estate parallel, I think the model could be calibrated far better than that. There will always be a need for independent diamond appraisers, just like there is one for real estate or any other type of property. This could just complement that. Especially since it seems so hard to accurately determine the qualities of a stone.

I''m probably being overly optimistic, mostly due to my inexperience in this field, but I would imagine with the progress in science, that there would be a tool out there for professionals similar to an MRI (cat-scan) that could decompose a stone down to it''s molecular structure, and you could get the precise stone parameters (similar to DiamCalc). If there isn''t such a tool out there, there should be one. This would result in accurate certifications and maybe a better industry structure? Which is turn would allow standardized pricing? It just seems so "stone-age" to look at a small stone with a 10x magnifier and rely on "experience" to see (guess) such complex parameters.

Dan.

 

[denverappraiser]

I make a living providing reliable advice to my clients and I have a substantial investment in equipment to allow me to do that. I routinely am asked to inspect stones that already have reports from other labs and/or appraisers. I'm something of an insider available for hire. There are hundreds of gem labs out there. Some are ‘boutique’ sorts of services like I and others here offer and others are large production grading operations. Each serves their own niche. I give the same advice to everybody in your situation, even the readers of my own reports. The first things to read on an appraisal or lab document are the signature and the qualifications, not the grade or the value conclusion. It’s up to them to convince you that you should be interested in their opinions and the default answer is NO. Contrary to the wikipedia world view, all opinions are NOT of equal merit. If you don’t have reason to trust the grader, ignore their report in it’s entirety. Don’t try to convert it to what some other lab might say, and don’t try to discount it using some formula to offset inaccurate information.

Back to the analysis issue. I think you may be confusing the client and consequently the purpose of the reports. The lab’s clients are dealers, not consumers, and the report is intended to make a particular stone more saleable. This is not to say that the majority of labs are deliberately reporting false information but there are some very subtle details, like the report format or the selection of grading scales and the application of those scales, that inject a bias into the dataset. It’s a delicate line that the labs need to dance on between maintaining their own credibility and participating in a commercial reality. This also has a parallel in real estate where the client and primary intended user is (usually) a bank, not the homeowner or even a potential buyer. This absolutely colors the results and everything from the value conclusion to what information needs to be included are affected by it. A report from an appraiser/inspector hired by a potential buyer and designed to uncover potential defects as part of their shopping process will look VERY different from one hired by a bank to decide if they will approve a mortgage, even if they are describing the same property.

You are stating as facts information that I and others are telling you is variable. That’s what makes your equation difficult to prepare. You’ve got 3 known’s (weight, shape, price) and 3 unknown’s (cut, color, clarity) and what you wish you had was 5 known’s (weight, shape, cut, color, clarity) and 1 unknown (price). Thinking back to my algebra days, you simply don’t have enough information to accomplish your stated objective.

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

 

[addiction]

You are stating as facts information that I and others are telling you is variable. That’s what makes your equation difficult to prepare. You’ve got 3 known’s (weight, shape, price) and 3 unknown’s (cut, color, clarity) and what you wish you had was 5 known’s (weight, shape, cut, color, clarity) and 1 unknown (price).

I guess I''m getting a bit lost here... are you saying that if I see this Round 1.02ct ACA AGS0 H SI1 selling for $6,320 that is not what I''m looking at? I hope that with all the intervention the seller might have had, AGS didn''t say that this might me A 0.98 AGS2 I SI2, right? I understand that some things might be borderline, and it would make sense in that case to have something like H- or H+ to indicate that.

Maybe I''m being overly simplistic in my approach, but my point is that a "similar" Round 1.02ct ACA AGS0 H SI1 should cost $6,320. And it does, if you do a search on WF for 1.02 ACA, you find 3 Round 1.02ct ACA AGS0 H SI1 for $6,320 ((1) (2) (3)).

Now I wanted to take this a step further and figure out what I should expect if I''m looking for a "similar" Round 1.035ct ACA AGS0 H SI1 and I found it at $6,412. Clearly, when the price was set, the difference of $92 comes mostly from the increased weight.

Now I want to find what a Round 1.02ct ACA AGS0 G VS1 is and it is $9,500.

How much of that difference is due to color, how much due to clarity? What about proportion, depth, symmetry, girdle, angles, culet, polish, fluorescence, light return, HCA score?? How are those impacting the price? So, you''re right, I am taking these parameters as set mostly because I''m not an expert and I wouldn''t know what to look for in a stone anyway... especially with a loupe...

I saw a few posts on this board and other places that a lot of research is being done in diamond computer modeling and there is a lot of competition out there as to who will come out first with the most credible solution. When we get there I think we would have reliable statistics across labs.

 

[Sharon101]

Im not an expert but I have a belief that it is the unique combination of the 4 C`s as well as the 4 C`s individually that make the price what it is.

 

[denverappraiser]

A search in the database of 1.01-1.02/H/SI1/round produces 837 offers from the same list of a dozen or so dealers ranging in price from $3012 to $6056. What’s the difference?

What do we know about this stone (the one you listed)?
Round 1.02ct ACA AGS0 H SI1 selling for $6,320

As opposed to, say, this one, being offered from the same dealer in the same marketplace and on the same day for roughly half the price?
http://www.whiteflash.com/round/Round-cut-diamond-922945.htm

I haven’t seen either stone but my guess is that stone #1 beats #2 in every measurable category (except price of course) but how do you propose to address this in your statistical analysis? I’m guessing this because I know the source and assign it a high level of credibility. In this case, AGSL for clarity and color and Brian Gavin’s ACA grade for cutting. I suspect you’ve never met Brian and, prior to arriving here on Pricescope, you had never heard of ACA as a brand so you probably would assign a different credibility value to that particular tidbit but it’s the nature of statistics that you MUST assign a credibility level to your sources. So what do you use instead? In reported shape/weight/color/clarity these stones are effectively identical. The info for color & clarity is from an unidentified EGL lab (there are several and they are not all the same) and the info about cutting is nearly completely absent. Do you assume that it’s as good as can be within the table/depth parameters you’ve been given or do you assume the worst? What’s the premium you apply for the AGS branding as opposed to the EGL branding? How about the ACA brand? Is stone #1 worth more because it’s presented with tons of information to assist in shopping while stone #2 is provided with next to nothing? As a shopper, it certainly would be for me, the only question would be how much. What’s the affect of ideal/ideal polish & symmetry vs. good/good (graded using completely different scales)? Using your statistical analysis, how do you compare these two stones? One thing we know, in the aggregate, these two differ in price by roughly a factor of two and the difference seems to exist entirely outside of the statistical data analysis that you’ve suggested. I suppose you could conclude from this that #2 is a bargain and in a certain sense it is but I suspect that the vast majority of the shoppers here would choose #1 anyway, despite the higher price. Is it still a bargain if you don’t get what you want?

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

 

[addiction]

Neil, stone no. 2 you pointed out is not AGS certified and most definitely can''t be "priced" without more information. Most likely it is as you said, a stone not very well cut, hideous proportions, maybe even fish-eye, for all we know. The discount comes from the lack of information as well, as strmrdr pointed out in an earlier post.


I totally understand your point of view, not being able to rely on cross-lab data, that''s why I went on a tangent about Tod Gray''s post and Sergey''s comments. I do believe, though that I could do this for starters within the same lab metrics and get a sense on what the market is currently pricing for changes in weight, color, etc.

Cross-lab analysis does pose a problem as you pointed out, at least until there will be some common ground (if ever). Developing a cross-lab chart as you pointed out previously can be done as well, but that analysis would probably be best done by appraisers like yourself, who could verify the accuracy in the grading reports and build a cross-comparison.

 

[WorkingHardforSmallRewards]

Date: 5/28/2008 9:13:56 PM
Author: addiction

I understand that some things might be borderline, and it would make sense in that case to have something like H- or H+ to indicate that.

Have you really gone out and looked at stones of various colors and clarities with your own eyes?

Bring along a loupe and a few friends. Look at several stones of the same color and see if your friends and you can come up with some kind of agreement on what should be an H- H or H+

(by the way, consistency is really the issue we were addressing when it was suggested to you that you focus on AGS and GIA reports)

Frankly, I know that I could not possibly consistently day from day grade such small changes in color myself. I dont think you realize how small such a difference would truly be and how the colors you had seen prior to grading the diamond, how tired your eyes were on that particular viewing, how miniscule changes in ones eyesight or color sensitivity would affect the color grade.

Similar ideas exist with clarity grading.

To be honest with you, right or wrong, some of the things you have said made me think that you dont know anything about actual diamonds yet. In addition to the advice of many before me, which would say that in order for you to pick an exceptionally beautiful diamond via grades you must first understand what those grades mean and should thus expend your energy on learning those, I would also say that it would be much easier for you to work out a complex statistical formula if you first had a firm grasp of what the symbols you were working with represented not to mention spent a bit more time in the market getting more familiar with real world pricing after having truly learned what the symbols mean.

That aside I did want to share, from my small experience, though you are welcome to disregard it my short summary on diamond pricing. I have found that Ct weight is the most important indicator of price, outside of very rare colors and reasonably within the range of the average wedding ring weight. I have seen color and clarity as being fairly consistent on their impact on price, and that cut is generally the least important in regards to price(excluding branded cuts) though is truly no less important to the beauty of the stone and perhaps has an even higher cut off point than color or clarity in terms over eye visible impacts.

 

[addiction]

It was never my intention to come across as having any experience whatsoever into what''s involved in grading a stone. I''m not a gem appraiser, nor do I have any intention of becoming one. I probably jumped a little ahead of myself suggesting different color grading systems.... I was only considering the fact that it might improve my data''s statistical reliability...

You are absolutely correct, I have no experience with diamonds, as do the vast majority of people who buy retail diamonds in this country. That''s why I (we) rely on expert opinions on these matters (ie. The Certificate) and that''s why boards like this exist. I do appreciate all the hard work and sweat involved in creating such a universally-accepted-as-symbol-for-beauty/love as a diamond and the hard work involved in grading and appraising them. That''s why I''m paying for it!


Your expertise in pricing seems to be consistent with what I''ve experienced in my short endeavor at the local B&M. Since I''m not part of the industry, I''m just your average consumer who never had a real diamond in his hand, it seems only natural to me that it''s all stats... just like everyone has a Fantasy Team, but never pitched once...