Risk of not getting a brightest diamond

[oceanbeach]

I''m trying to understand the risk of not getting a brightest, most sparkling diamond and a H&A diamond by buying a diamond from a on-line vendor (eg Union Diamond) who does not provide a picture and ideal scope image of the diamond. Assuming that the diamond I would purchase is AGS 000 or GIA cut grade-Excelllent and HCA score is less than 1.5, what is the probability (%) that I don''t get 1) H&A diamond and 2) brightest (e.g at least 1 very highs and 2 highs in BrilliantScope)? Also, what''s the worst I could get? ...will I get at least 3 highs in BS?

Also, what do you think of probability below assuming the stone has HCA score less than 1.5?

What % of AGS 000 won''t have at least 1 very highs and 2 highs in BS?
What % of AGS 000 won''t be a H&A?
What % of AGS 000 would suffer from painted or digged-out girdle?
What % of GIA Excellent won''t have at least 1 very highs and 2 highs in BS?
What % of GIA Excellent won''t be a H&A?
What % of GIA Excellent would suffer from painted or digged-out girdle?

Thanks!

 

[belle]

if getting a h&a diamond is that important to you, then you need to at least get h&a pictures.
if scoring well on the bs is that important to you, then you need to find someone that provides bs results.

you can''t guess either of the above based on the grading report.

 

[diamondseeker2006]

And if you haven''t already, read through GoodOld Gold''s tutorial pages. You''ll find out that AGS0 does not always outperform other diamonds. At this point, I''d just like to call Jon and tell him to find me a great stone! I think he really knows what to look for and can evaluate the stones as well as any jeweler anywhere.

 

[kenny]

People hate me for this but I like to keep it simple.

I''d go for an AGS 0 (recent report) that with an HCA near 1.0 and with an X that falls in the middle of the HCA chart''s areas for AGS ideal and GIA excellent.

You can''t go wrong.

 

[froufrou]

diamondseeker....you really like goodoldgold, dont you????
thanks for all your great advice earlier by the way.

ocean: ive run a ton of numbers of diamonds from bluenile through the HCA and the AGS000 tend to get below 2 while GIA Excellent do and dont half the time, w/ GIA "Very Good" and "good" sometimes getting awesome HCA ratings too. but i am just learning this stuff, so this is just my personal experience over the past week.

 

[diamondseeker2006]

Date: 5/18/2006 12:48:19 PM
Author: froufrou
diamondseeker....you really like goodoldgold, dont you????
thanks for all your great advice earlier by the way.

ocean: ive run a ton of numbers of diamonds from bluenile through the HCA and the AGS000 tend to get below 2 while GIA Excellent do and dont half the time, w/ GIA ''Very Good'' and ''good'' sometimes getting awesome HCA ratings too. but i am just learning this stuff, so this is just my personal experience over the past week.

Lol! I do think Jonathan has the best website for diamond knowledge by far! However, you recall, I''m sure, that I gave you stones from James Allen to look at, so I spread around the recommendations! (My BIL bought a WF diamond I recommended, and I have a stone now from Dimend Scaasi to look at, looked at one of Wink''s previously, so I pretty much like them all!)

I think Kenny has the right idea, if one prefers to not go insane! (That or call Jonathan and ask him to pick one!)

 

[oceanbeach]

Thank you everyone for your advise!

Date: 5/18/2006 11:59:58 AM
Author: diamondseeker2006
And if you haven''t already, read through GoodOld Gold''s tutorial pages. You''ll find out that AGS0 does not always outperform other diamonds. At this point, I''d just like to call Jon and tell him to find me a great stone! I think he really knows what to look for and can evaluate the stones as well as any jeweler anywhere.

Yes, I''ve read and learned a lot through their site too! That''s why I know that there is a risk, but not sure how much of risk.... Ifm considering Union Diamond because I will save some money on the setting that I want, which is $400 cheaper than if I were to bring the stone purchased at GOG to local store to set. GOG is my favorite as they provide results from various test equipment, including BS, so I may end up going with them just to be safe.

 

[JulieN]

Date: 5/19/2006 6:42:56 AM
Author: oceanbeach

GOG is my favorite as they provide results from various test equipment, including BS, so I may end up going with them just to be safe.

Only opponents of BrillianceScope call it BS...

 

[Rhino]

Date: 5/19/2006 6:50:08 AM
Author: JulieN

Date: 5/19/2006 6:42:56 AM
Author: oceanbeach


GOG is my favorite as they provide results from various test equipment, including BS, so I may end up going with them just to be safe.

Only opponents of BrillianceScope call it BS...

LOL!

 

[Mara]

Date: 5/19/2006 6:42:56 AM
Author: oceanbeach
GOG is my favorite as they provide results from various test equipment, including BS.

______________________


Now there is a phrase no vendor wants to hear!!

Maybe call it BScope. hehehe.

 

[Rhino]

Hi Ocean,

Just some insights to the Bscope and answers to your questions ...

Also, what do you think of probability below assuming the stone has HCA score less than 1.5?

What % of AGS 000 won't have at least 1 very highs and 2 highs in BS?

For the most part I'd say most at the least score VH in the colored light. This is because the paviloin mains in AGS ideal cuts are reflecting back strong light at high angles. To get the other meters to jump in the VH range not only do the crown and pavilion slope angles have to be ideal but also their *azimuth* angles have to fall within certain tight tolerances as well for maximum intensity. In brief ... slope angles are the angles most commonly reported on AGS/GIA/Sarin/Helium/OGI Reports. Ie. 34.5 crown angles/40.9 pavilion angles are the slope angles. These angles are measured in a north/south orientation. Azimuth angles are oriented in an east/west orientation so if a pavilion facet (main or lower half) is twisted to far off in another direction (east or west) this impacts light return and the Bscope is a very sensitive photospectrometer and can *see* these deviations. When both slope and azimuth angles are ideal and cut to maximize light return that'll result in a triple VH. One point of note however ... having used the Bscope now for 6 years on a daily basis I can tell you that there are many instances wherein a layman can not see the differences from a 2/3 VH's to a 3/3. Sound advice would be that it is good technology to consult but don't hedge all bets on only 1 technology alone and I would say that about any technology.

What % of AGS 000 won't be a H&A?

A *true* H&A ... not many.

What % of AGS 000 would suffer from painted or digged-out girdle?

From our research we've found both GIA and AGS to be on the same page regarding digging. Once the upper girdle/lower girdle angle relationships reach a certain threshold they get dinged for light performance on dug out stones. Since the factories who send their diamonds to AGS for reports want to acquire the "Ideal" grade a very small percentage if any will suffer from digging.

With regards to painting GIA and AGS are not on the same page and this is partly due to AGS adopting reflectors as a primary source for determining the grade while GIA centered their studies on how observers judged the face up appearance when comparing the stones side by side in a lighting environement accurately depicting brightness (over 70,000 observations recorded). Since AGS is more lenient on painted girdle diamonds you stand a much greater chance of finding painted stones with AGS reports since they don't take the hit in their PGS software. AGS does however have a threshold for painted girdle diamonds, its just not as conservative as GIA's threshold.

What % of GIA Excellent won't have at least 1 very highs and 2 highs in BS?

Since GIA's Ex grade covers a broader span than AGS Id Grade (naturally a 5 grade system will not be as tight as an 11 grade system) it would depend on the angle combinations of the GIA Ex. If it is a combination of proportions that produce even the slightest leakage under the table (say if pavilion angles fall over the 41 degree threshold) with 34-35.x crown angles, it is possible nothing will score in the VH range. Keep in mind the Bsope is an ultra sensitive photospectrometer. More sensitive I could argue than the human eye. This however doesn't mean the stone will not be beautiful or ever preferred over others. I recently published such a study we conducted here in our store with a stone that scored a medium/high/medium next to a high/very high/high and after 30 observations by regular folk 90% of them picked the medium/high/medium!

This was a rare case though and only applies to the types of stones that were used in this survey.

What % of GIA Excellent won't be a H&A?

Most will not.

What % of GIA Excellent would suffer from painted or digged-out girdle?

None with this note. GIA will not ding a diamond for painting or digging if it doesn't impact the face up appearance. GIA does allow painting and digging to a certain minimum threshold. It has been previously and erroneously stated on this forum that GIA is mass grading all painting and digging and this simply is not true.

Hope that helps.

Peace,

 

[Rhino]

Date: 5/19/2006 1:22:44 PM
Author: Mara

Date: 5/19/2006 6:42:56 AM
Author: oceanbeach

GOG is my favorite as they provide results from various test equipment, including BS.

______________________


Now there is a phrase no vendor wants to hear!!

Maybe call it BScope. hehehe.

SO TRUE! We''re always joking about that here Mara saying what BS is the BS telling us today.

Na ... seriously, we love the tool and how it communicates certain elements about diamond appearance but are also are quick to point out its limitations to those who place too much emphasis in any one technology.

Like your new avatar btw. You kept whetting my apetite everytime I saw that ice cream type of thing you used to have.

I kinda miss that one.

Warm regards,

 

[oceanbeach]

Hi Rhino,

Thank you very much for the detailed explanation. Also, thanks for your great educational website! Ifve learned a lot through the site.

It seems that the probability of getting a pretty nice stone by going with GIA excellent with good proportions. So, I guess the question comes down to whether I really have to have a H&A diamond or not. I know that the topic, gH&A vs. Ideal cut,h has been discussed a lot in this forum, but I think some feels that it is worth getting H&A, and others feel that there is no visual difference. What are your thoughts on this? Is it really worth getting H&A??

I saw a video in your website that shows a comparison of AGS 000 and H&A stones, but I canft find it now. Can you send me the link, if you can?

Thanks!

 

[oceanbeach]

Additionallyc.
So, what is really gTrue H&Ah? Ifve heard that H&A doesnft assure brilliance etcc Whatfs the main advantages of getting a H&A instead non-H&A?

 

[Garry H (Cut Nut)]

H&A''s is more about knowing and being able to see for your self that the stone is symmetrical.
But H&A''s occurs across a very wide range of proportions - most are good - but some are not.

It is as some people say regarding clarity - is it a "mind clean" diamond?

 

[salmon]

Rhino,

I love your website too. But I do have one question: When are you going to post something on Radiants? Don''t you know you have eagerly awaiting fans out here Coming Soon?

 

[WinkHPD]

Date: 5/19/2006 2:57:16 PM
Author: Rhino
With regards to painting GIA and AGS are not on the same page and this is partly due to AGS adopting reflectors as a primary source for determining the grade while GIA centered their studies on how observers judged the face up appearance when comparing the stones side by side in a lighting environement accurately depicting brightness (over 70,000 observations recorded). Since AGS is more lenient on painted girdle diamonds you stand a much greater chance of finding painted stones with AGS reports since they don''t take the hit in their PGS software. AGS does however have a threshold for painted girdle diamonds, its just not as conservative as GIA''s threshold.

You make this sound as if painting wre a bad thing and it is not. Painting, done properly, can enhance the visual beauty of a stone, allowing greater light return and less leakage. GIA does NOT adequately address this issue and does in fact penalize performance enhancing amounts of painting.

Wink

 

[Rhino]

Hi Ocean,

Thanks for the kind words man.

It seems that the probability of getting a pretty nice stone by going with GIA excellent with good proportions. So, I guess the question comes down to whether I really have to have a H&A diamond or not. I know that the topic, gH&A vs. Ideal cut,h has been discussed a lot in this forum, but I think some feels that it is worth getting H&A, and others feel that there is no visual difference. What are your thoughts on this? Is it really worth getting H&A??

Good question. Here''s my straight up on this. There are non H&A diamonds out there that almost make the H&A status and then there are non H&A stones that have what I would consider chaotic or common optical symmetry. We show examples of this in our article on the subject but below are graphics demonstrating the difference between what we grade as Ideal optical symmetry, Near Ideal optical symmetry and Common optical symmetry.

When viewing Ideal alongside Near Ideal it is about impossible to see the differences. As Garry mentioned its more of a "mind clean" thing. The thing is these *almost* H&A stones cost us dealers the same amount as the H&A''s do in most circumstances but will sell them for less to move them. They are what you could consider, these factories mistakes.

When you consider the prices that H&A''s are selling for on the net compared to what common kaka is selling for in most local jewlery stores many consumers find it just worth it to get an H&A.

Probably the biggest difference in appearance would be between those and Common optical symmetry. As you can see from the graphic below the reflector image is not symmetrical and these have the greater difference in appearance than the above. In our instructional video on scintillation you can get an idea how these vary in appearance under both diffuse daylight and spot lighting conditions.

I saw a video in your website that shows a comparison of AGS 000 and H&A stones, but I canft find it now. Can you send me the link, if you can?

My apologies but the rules prevent me.

Thanks for your questions.

Kind regards,

 

[Rhino]

Date: 5/20/2006 6:57:12 AM
Author: oceanbeach

Additionallyc.
So, what is really gTrue H&Ah? Ifve heard that H&A doesnft assure brilliance etcc Whatfs the main advantages of getting a H&A instead non-H&A?

Hopefully my response above covered this for ya except I see I forgot the graphics. Here it is. If you need clarification on anything let me know and I''ll expound.

Regards,

 

[Rhino]

Date: 5/20/2006 10:13:34 AM
Author: salmon
Rhino,

I love your website too. But I do have one question: When are you going to post something on Radiants? Don''t you know you have eagerly awaiting fans out here Coming Soon?

Hi salmon! We love you too!

Thanks for you inquiry about radiants. Actually at the early part of this year we began featuring a new proprietary square radiant cut with light performance like we''ve never seen in radiants. My staff has been bugging me to do a write up on these but I''ve been having too much fun with video stuff which I''ve been waiting years to do.

You''ve just put a little fire under me to get this done so I''ll begin working on it. If you have any questions in the meantime though don''t hesitate to call.

Warm regards,

 

[Rhino]

Date: 5/20/2006 10:26:00 AM
Author: Wink

Date: 5/19/2006 2:57:16 PM
Author: Rhino
With regards to painting GIA and AGS are not on the same page and this is partly due to AGS adopting reflectors as a primary source for determining the grade while GIA centered their studies on how observers judged the face up appearance when comparing the stones side by side in a lighting environement accurately depicting brightness (over 70,000 observations recorded). Since AGS is more lenient on painted girdle diamonds you stand a much greater chance of finding painted stones with AGS reports since they don''t take the hit in their PGS software. AGS does however have a threshold for painted girdle diamonds, its just not as conservative as GIA''s threshold.

You make this sound as if painting wre a bad thing and it is not. Painting, done properly, can enhance the visual beauty of a stone, allowing greater light return and less leakage. GIA does NOT adequately address this issue and does in fact penalize performance enhancing amounts of painting.

Wink

Greetings Wink,

I respect your opinion and your passion bro. In many ways we have alot in common regarding our passion for what we do and I love this about you. In this great country of ours I''d even fight for your right to disagree.

In common lighting environments depicting brightness I''d have to disagree. I note a decrease in brightness in stones exhibiting a certain degree of painting. I did once think as you did Wink so I understand where you are coming from and sympathize with your view.

It was after many stones leaving here to be compared by people all over the country over the course of roughly 10 months (back in 2000/2001) that forced me to take a harder look at the issues. You know I am a strong advocate of reflector based technologies and the information to learn from them but it was actually the introduction and study of both AGS ASET and GIA''s DiamondDock that convinced me beyond doubt why a majority of consumers we were sending these comparisons to chose as they did. An unexpected part of our research was we were finding direct corellations with the 2 newly acquired technologies. When GIA released their studies on this it was not a surprise to me personally as we were conducting observation testing ourselves over the past 6 years.

Do I criticize a person''s choice for painted stones? Not once in all the years I''ve been participating on these forums will you find one word from me doing this. In fact if you search among my postings you will find the opposite Wink. Till this day I still show this comparison and if a person chooses for one, more power to them. I am for people getting what pleases their eyes most, regardless of my personal opinion. If its a painted girdle stone, then by all means they should purchase it. If it''s a diamond with 144 facets, so be it even if it wasn''t my cup of tea. I understand folks who are familar with reflectors are finding it hard to comprehend why GIA has taken this stance with regards to their cut grading system but I understand it Wink. The key to understanding GIA''s cut system is learning face up appearance in common lighting. As Al Gilbertson said around 1999 on the GemKey forum ...

—“The real question is--what is being done to scientifically demonstrate what is the best overall cut for a round diamond?...Just because light doesn''t leak out the bottom of a diamond and just because that diamond shows a symmetrical pattern in a viewing device, does that mean that light is efficiently gathered from around a viewer and returned to them in it maximum potential from that diamond?” He felt that there was not enough evidence to link the two. Al explains, "What has not yet entered into the discussion is how our eye and brain work together to view these phenomena. There are many new areas related to how the eye and brain work together that should be discussed before we can arrive at such definitions. I may be able to have an instrument that quantifies the actual lumens a diamond reflects to my eye. In reality my eye may not see what that instrument says exists." He pointed out "The FireScope doesn''t tell you how effective light is gathered and returned to a viewer unless you do a lot of work with its images." He had found that "The most essential elements are that neighboring facets need to be returning light to the viewer from different entry points. The more different the entry angle the more dramatic the observation." (quoted from our article "A Comprehensive Guide to Reflector Based Technology")

My most current project (thanks to a forum member headlight) is comparing GIA Ex''s to GIA VG''s to show the differences in face up appearance plus I''m working on a seperate project just on painting and digging wherein I record the differences in appearance and the *why''s* behind GIA''s system which Al Gilbertson was directly and hands-on involved in. For clarification of the readers here Al Gilbertson is the inventor of muti-colored reflectors and is perhaps more intimate with how their results corellate to human observation than any of us in the field. He is the one who sold the patent to AGS for the ASET.

While on the subject I will say this ... There are lighting environments in which it is impossible or near impossible to see any difference (I have this recorded too) but then there are others wherein it is much easier. Also GIA does not ding all painted/dugout girdles. To my knowledge it is only to the degree wherein it is visible. At least that has been my experience to date.

Great to hear from ya Wink and keep the passion.

Your friend and colleague,

 

[kenny]

Rhino, does GoodOldGold sell diamonds with painting or digging?

 

[Rhino]

Date: 5/20/2006 3:46:27 PM
Author: kenny
Rhino, does GoodOldGold sell diamonds with painting or digging?

Wazzup Ken. We have a couple of painted stones here and perhaps 1 with digging. The vast majority of our inventory doesn''t and hasn''t been since around 2001.

Peace,

 

[oceanbeach]

Hi Rhino,

Thank you very much for all the explainations!

I stopped by local jewelry store and compared a 1 ct diamond with ISEE2 score9.6 and another on with 7.9. I couldn’t really see the difference…. But, I guess it may be the “mind clean” thing, I still feel that I may want a H&A stone with triple VH. well…I have to think more. This is tough to decide!

Regarding the link, I understand.

Last question, some suggested that I should ask a vendor to look for what I''m looking for. How difficult is it to find the following stone? My boyfriend is not ready to purchase it now though (not until fall or so), but I''m curious.

Budget - $5800
H&A with BS score triple VH if possible, if not 2VH and 1H, and HCA score lower than 1.5
1.05-1.15 carat
D – G
Completely eye-clean SI 2 (with no durability issues)

Thanks,

 

[belle]

Date: 5/21/2006 8:09:45 AM
Author: oceanbeach


Budget - $5800
H&A with BS score triple VH if possible, if not 2VH and 1H, and HCA score lower than 1.5
1.05-1.15 carat
D – G
Completely eye-clean SI 2 (with no durability issues)

if you want a well cut stone for $5800 you will be looking at a 1ct. g/si

 

[JohnQuixote]

Date: 5/19/2006 2:57:16 PM
Author: Rhino

None with this note. GIA will not ding a diamond for painting or digging if it doesn't impact the face up appearance. GIA does allow painting and digging to a certain minimum threshold. It has been previously and erroneously stated on this forum that GIA is mass grading all painting and digging and this simply is not true.

With respect to Rhino’s opinion, there is disagreement on this issue.

Why? Because the GIA downgrades some diamonds for painting/digging that would receive AGS0 in light performance, and they do it without individual face-up analysis. Instead they use a profile (side) view. Unfortunately this does not tell the story with regard to performance: How painting/digging might influence performance in a diamond - or not - depends on overall configuration: Pavilion main angle, lower girdle length, crown main angle, star length and table size all change the playing field. As you cut near Tolkowsky proportions (like diamonds many PS vendors carry) a larger degree of painting is safe, especially when coupled with optical symmetry. Analysis & ray-tracing studies by the AGS confirm this. So do fine-make cutters producing some of the world's finest diamonds, and many thousands of consumers over decades of decision-making. For now, though, the GIA chooses to stereotype without taking overall configuration into account.

As a humorous comparison, GIA's painting/digging judgment is like stereotyping blondes as dumb. Not good.

The total personality of each person, or each diamond, should be assessed individually. Simple proof: This is why painted and traditional diamonds alike can, and do, earn the AGS Ideal grade in light performance, where each diamond is able to stand on its own merits.

Are there extremes of painting/digging? Yes - and reasonable people agree that extremes should be penalized in any approach. But reason also says a side view won't tell the story regarding face-up appearance.

So, Rhino is correct: Some experts do believe this girdle stereotyping by GIA is a mass grading shortcut. It seems to be in-keeping with other shortcuts in their system, such as case study) have received criticism from many committed to grading precision and accuracy.

On a positive note, the GIA is still young at cut-grading. With time I believe kinks will be worked out. Their having a system this year is a positive step (where they had none before). In the macro, their system may serve the public and trade-at-large, but if they wish to serve detail-minded manufacturers, science pros, sellers - and buyers like our picky Pricescope crowd - it will take some refinement.

Another thread with info from GIA and prior discussion on this topic: GIA on Painting and Digging

 

[RockDoc]

AGS''s new software.....

Having just returned from the AGS Conclave, and getting the PGS software, I am noticing some very interesting results for stones I''ve checked using it.

This is some very advanced ray tracing analysis which appears to be far more than the ray tracing technology that is in Diamond Calc.

What I''ve found very interesting is that the software is capable of picking up the slightest variance of the proportional imaging of the stone.

I''ve even seen these variances using the software in stones that are of the AGS 0 grade.

It does analyze and reports a numerical rating for the following

Brightness
Dispersion
Leakage
Contrast
Durability
Tilt
Weight Ratio
Girdle
Culet
Symmetry (examination in person required and entered in to the software)
Polish (examination in person required and entered in to the software)

It also issues a grade for

Light Performance Deduction
Proportion Deduction
Finish Deduction

and then Reports the AGS Cut Grading based on the NEW AGS system.

This would be very helpful for estimating the AGS cut grade for GIA graded stones, as well as reporting more indepth information about those with AGS reports. It does point to even the slightest variance within each grade.

As I am able to image more stones, I''ll be writing about what things I''ve observed.

Does anyone else here have the PGS software? It would be an interesting study to see just how exactly matched these reports would be.

So for consumer''s who want to know the estimated AGS new grade, for EGL / GIA graded stones, this is a real advantage, as well as for older AGS reports where the only AGS grading is generated by the old AGS grading system - such as is reported with the Sarin, Helium and OGI software.

Additionally, the software will soon be updated to do the emerald cut and square stones. Good for the emerald cut and asscher cut diamonds.

So who has this and wants to work doing a cooperative study?

Rockdoc

 

[WinkHPD]

John, excellent comment on the GIA grading shortcuts.

Date: 5/22/2006 3:50:20 AM
Author: RockDoc



It does analyze and reports a numerical rating for the following


Brightness

Dispersion

Leakage

Contrast

Durability

Tilt

Weight Ratio

Girdle

Culet

Symmetry (examination in person required and entered in to the software)

Polish (examination in person required and entered in to the software)


It also issues a grade for


Light Performance Deduction

Proportion Deduction

Finish Deduction

and then Reports the AGS Cut Grading based on the NEW AGS system.

,snip>

Roc, I believe that you are in partial error here. The diamond grader must supply the symmetry and polish grades and enter them into the software. The software does not then actually determine the finish deduction, but the grader. The software will then issue the final grade based on this additional input from the grader.

Wink

 

[RockDoc]

hi Wink


Symmetry (examination in person required and entered in to the software)

Polish (examination in person required and entered in to the software)

I thought I did make that clear with polish and symmetry as I posted it above........

I do agree with you that the diamond needs to be seen to enter in the info on those two characteristics.

Do you have the PGS software?

Rockdoc

 

[WinkHPD]

No, I have attended the classes on how to use it and the ASET, which I do have. Since I do not do appraisals on other peoples''s stones and since I sell almost exclusively AGS graded diamonds I have not found a need to spend the money for the software. I think it is a great program though and were I doing independant appraisals I would definitely own it.

Wink