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First time diamond buyer. Please help!!

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gaga

Rough_Rock
Joined
Dec 19, 2006
Messages
2
Hi all,


My boyfriend has proposed to me with an engagement ring with the following specs:


Shape and Cutting Style: Round Brilliant (with GIA certificate)


Measurements: 8.01 ?8.09 x 5.05 mm


Carat Weight: 2.00 carat


Color Grade: D


Clarity Grade: VS1


Cut Grade: Excellent


Polish: Very Good


Symmetry: Very Good


Fluorescence: None


Table: 57%


Total Depth: 62.7%


Crown Depth: 15.5%


Crown Angle: 35.5 degrees


Pavilion Depth: 44%


Pavilion Angle: 41.4 degrees


Girdle: medium to slightly think (faceted)


Cutlet: None



My boyfriend and I are first time diamond buyers.The jeweler told us that this is an ideal cut.However, after I googled about ideal cut, I found that GIA and AGS have different cut grading systems and that AGS has stricter parameters.According to the AGS cut grading system my diamond is an AGS 1 grade diamond due to the Pavilion Depth (44%) and the Pavilion Angle (41.4 degrees) are slightly outside the upper limits of the ideal range which are 43.8% and 41.2 degrees, respectively.Yet, GIA has graded this diamond as Excellent.


Further, I found that some websites say that the total depth of 62.7% is the upper limit of the ideal range but some websites say the upper limit should be 62.5% or even 62.3%.I also noticed that a 2 carat round diamond should have a diameter of 8.2 mm and the length should be 4.9 mm but the average diameter of my diamond is 8.05 mm and the length is 5.05 mm.Does it mean that my diamond is a deep cut diamond?


I've also tried the specs with HCA and the results are as follows:

Light Return: Good

Fire: Fair


Scintillation: Fair


Spread: Very Good


5.1 - Good - Only if price is your main criterion.

What does this mean?Is it good or bad?


I have told my fiance about the results of my research.He said he is happy to exchange it for me and is willing to pay more for an ideal cut diamond since I am going to wear it everyday for the rest of my life.Some say untrained people will not be able to tell the difference between an AGS grade 0 and an AGS grade 1 and that diamonds with proportions with the range of AGS 0 and 2 are considered very fine cut and provide exceptional brilliance.Our question is: will an AGS grade 0 ideal cut diamond look significantly different from mine (AGS grade 1) in terms of fire, brilliance and scintillation?Is it worth to pay more for an AGS 0 grade diamond?


Your opinions / advice / comments will be much appreciated.Many thanks!

 

Dee*Jay

Super_Ideal_Rock
Premium
Joined
Mar 26, 2006
Messages
12,928
Hmmm... honestly, if I were in your shoes I would return this stone and get a different one. A score of 5.1 is rather grim (and I did plug the numbers in again to make sure that it really was 5.1) and you are shy quite a bit of face-up size for what it should be.

Can I ask if you're committed to such high color and clarity? If you went down to even an F VS2 in the same size you would save quite a bit of money, or you could get a bigger stone for the same money. You maybe be able to go even lower than that in color; have you looked at lower colored stones to see what your tolerance is? As for clarity, depending on the inclusions, you could get an eye-clean SI2 that wouldn't look any different to the naked eye than an IF.

If you haven't done so already you might want to read up on the tutorials at the top of this page and you'll get even more knowledge about well cut stones and why this one isn't fabulous, and that will help you choose a better one in the future.

Also, about the HCA, read up on that too so you understand the parameters. You want a stone under 2 and you probably want one over .6, with somewhere being right around 1 as a "sweet spot." There are several threads on this, but these are some basic parameters.
 

pricescope

Ideal_Rock
Joined
Dec 31, 1999
Messages
8,266
Gaga, congrads with proposal
and welcome to the forum.

Looks like this stone is the heaviest (steep/deep) cut to make into GIA excellent cut grade and retain 2.ct weight.

You are right about differences with AGS, GIA, and HCA cut grading approaches. You are also correct about smaller spread (diameter) that diamond comparing to e.g. Tolkowsky cut with similar table size.

It still can look OK in a high open settings like 4-prong Tiffany and pavilion is clean. Otherwise, leakage can make it darker under the table.

If you like the stone and the price is right, you might still want to consider it. Otherwise, you should be aware of the problems with this diamonds and keep in mind that 1.9ct Tolkowsky cut diamond would look as large as this one.

Ask your jeweler about these issues and see what he/she will tell you.
 

scarleta

Brilliant_Rock
Joined
Feb 25, 2006
Messages
1,572
congratulations on the proposal.Happy for you.As for the stone with the little I know you may want to find a better one. One that would score much better..You have already educated yourself quite a bit in such a short while , so keep on reading here and good luck...
 

oldminer

Ideal_Rock
Trade
Joined
Sep 3, 2000
Messages
6,321
It is not a perfect ideal cut, but it is not a bad diamond, either. I think you should say THANK YOU and teach him about the further particulars of diamond buying in the years to come. There is time enough to perfect your future hubby.

Maybe he did the best he could and you will hurt him by not wanting the diamond he chose. He might want to reconsider his choice not only in diamonds, but in fiance's if you come on too strong. If the guy is a D-IF, then don't mess with the diamond he chose. There are fewer good men than good diamonds.
 

scarleta

Brilliant_Rock
Joined
Feb 25, 2006
Messages
1,572
now that is nicely said...definitely it would be easier to get a better diamond than a better man..
 

zhuzhu

Ideal_Rock
Joined
Mar 15, 2006
Messages
2,503
Date: 12/20/2006 11:41:21 AM
Author: oldminer
There are fewer good men than good diamonds.

EXCELLENT POINT AND STRONGLY AGREE!!!!
 

RockDoc

Ideal_Rock
Joined
Aug 15, 2000
Messages
2,509

Some say untrained people will not be able to tell the difference between an AGS grade 0 and an AGS grade 1 and that diamonds with proportions with the range of AGS 0 and 2 are considered very fine cut and provide exceptional brilliance. Our question is: will an AGS grade 0 ideal cut diamond look significantly different from mine (AGS grade 1) in terms of fire, brilliance and scintillation? Is it worth to pay more for an AGS 0 grade diamond?



I am a little puzzled as to how you reached the conclusion that this stone would be an AGS 1.

In order to ascertain this using the parameters of the NEW AGS cut grade system, the stone would need to either be graded by AGS, OR analyzed by using a scan from the .srn or .stl image files, and run through the AGS PGS software by someone who has this program, and is qualified to rate the symmetry and polish from seeing the stone in person to verify that the polish and symmetry is IDEAL.

A lot of what is on the internet about AGS cut grades is based on the old system which was "proportion driven".

The new system rates stones for light performance based on ray tracing calculations as well as the proportions and the ASET image.

There is more information on this at the AGS websites www.agslab.com and www.agsaid.com

Rockdoc
 

oldminer

Ideal_Rock
Trade
Joined
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Messages
6,321
"The new (AGS) system rates stones for light performance based on ray tracing calculations as well as the proportions and the ASET image."

1. The ASET image alone won't do it, because it is subjectively graded.
2. The calculations alone won't do it because they are too subject to measurement error and lack of sufficient detail to be completely reliable and all of us recognize that proportions alone are not sufficient for more than screening.
3. Using proportions for Calculated Ray Tracing end up not being good enough except for screening.

The end result is a palatable concoction of subjective grading and potentially erroneous calculations based on not so accurate measurements of limited parameters. I sure would hate to be hanging a very fine reputation on such a very tenuous hook all the while insisting it was the best system possible. It isn't.... However, I would grant it is improved from what it once was and may continue to undergo improvment. Will it ever be the best or the universal system? I doubt it, but RockDoc would definitely disagree.

We see it differently, but really both of us need to see the eventual outcome before we know for sure. The AGS system is still more an in-house system than one used all over the world and held as a universally accepted standard. Don't assume that the world has accepted it quite yet. It has a way to go.
 

Regular Guy

Ideal_Rock
Joined
Jul 6, 2004
Messages
5,951
The design of the accompanying certificate itself is different, and now always specifies a grade for light performance. See cut advisor, for a given table specified, will show the approximate parameters for current AGS0.
 

belle

Super_Ideal_Rock
Joined
Nov 19, 2004
Messages
10,285
only a stone that is graded by agsl as ags0 can be considered as such. if you want an ags0 diamond, get one.
 

Regular Guy

Ideal_Rock
Joined
Jul 6, 2004
Messages
5,951
Belle''s correct for more reasons than I know, to include the fact that typical examination of crown & pavilion angles takes an average of 8 or so facets, whereas an AGS0 will have been based on a 3 D model of some 57 or so facets, and a more precise description of the particular diamond at hand.

The extent to which there is a good match, anyway, with a standard AGS0 profile with a given crown & pavilion angle, and a GIA one, given your satisfaction with the fact that GIA is the likely cert is a good question, better answered by an expert here, but not often done taken on, per se. Generally, though, while AGS certs help to insure the high quality, both because a) it was sent there and b) then earned their quality grade, GIA is certainly a quality outfit, too, and even though their data is averaged...I''m betting a good HCA score, and set of angles conforming to a contemporary AGS0 is really very good news.

Additional data, as you can read here, always helps to lock the goodness of your choice. Then again, all you ever have is your eyes, so that''s not a bad reference point, too.
 

RockDoc

Ideal_Rock
Joined
Aug 15, 2000
Messages
2,509
Date: 12/20/2006 12:48:28 PM
Author: oldminer
''The new (AGS) system rates stones for light performance based on ray tracing calculations as well as the proportions and the ASET image.''

1. The ASET image alone won''t do it, because it is subjectively graded.
2. The calculations alone won''t do it because they are too subject to measurement error and lack of sufficient detail to be completely reliable and all of us recognize that proportions alone are not sufficient for more than screening.
3. Using proportions for Calculated Ray Tracing end up not being good enough except for screening.

The end result is a palatable concoction of subjective grading and potentially erroneous calculations based on not so accurate measurements of limited parameters. I sure would hate to be hanging a very fine reputation on such a very tenuous hook all the while insisting it was the best system possible. It isn''t.... However, I would grant it is improved from what it once was and may continue to undergo improvment. Will it ever be the best or the universal system? I doubt it, but RockDoc would definitely disagree.

We see it differently, but really both of us need to see the eventual outcome before we know for sure. The AGS system is still more an in-house system than one used all over the world and held as a universally accepted standard. Don''t assume that the world has accepted it quite yet. It has a way to go.
RE : Rockdoc would disagree.

My post above was directed at not accepting the old AGS system, when the new system is out, and having a consumer relying on "stale" info.


As to the accuracy and completeness of the system. I think you have to admit that it is the most advanced system out there at this time.

AGS is a very recognized organization, and have committed years of work and millions of dollars to come up with the system they now have.

I think the AGS has taken the lead on improvement of cut grading and unless GIA or someone else comes up with a better mousetrap, it will be considered as "the standard", along with future development and tweaking of it.

At least AGS has been very open about the technology, and has play an integral part in exposing its "secrets" of how it works, as compared to other analysis and grading instruments or "black mystery boxes" that are not as forthcoming about what they do as compared to AGS. Further if you feel the scanning instruments are not accurate, guess you feel that Sarin, OGI, and the Helium are worth the powder to blow them to hell either.

Dave, if you think ray tracing is inaccurate and incorrect, and that the ASET is dubious, then what is better at this time?
If ray tracing is only a sort elimination tool, as you''ve expressed, that trashes HCA, and Diamond Calc. If you doubt the efficiency of the ASET - I guess it is worse for the Idealscope, Firescope, Symmetry Scope and Mr. Okuda''s inventions of the past.

AGS''s research and development is based on many learned scientific experts such as Dr. Sasian and Sergey/ Octanus and Jim Caudill who is an engineer. It just wasn''t the compilation of just gemological experts.


Perhaps I am a "sheep" following what AGS has done, but until someone else comes up with something more provable I''d place my bets on AGS as far as being a viable and recognized STANDARD.

Rockdoc
 

oldminer

Ideal_Rock
Trade
Joined
Sep 3, 2000
Messages
6,321
The industry is indeed a herd of sheep. Some are being led and a few are not. Some sheep are lost. I consider you and many other good guys as being too easily sold a bill of goods. The AGS Standard is strictly an in-house standard and not universally agreed upon. None of the tools which rely on "calculation of measured parameters" are going to become true standards. Direct measurement of performance will be the eventual model for a universal standard of diamond performance.
The AGS and Peter Yanzter are acting in good faith to better the industry and have been extremely open in their process. It is the process which is flawed and not their intentions, which we acknowledge are 100% tops. If the quality of their intentions were equalled by the questionable science behind the system, it would be far better. They have done a great job of marketing and convincing people, but only AGS uses the AGS system at this time. A real standard will be the same one all over the world. We''ve yet to agree on it yet.
 

Regular Guy

Ideal_Rock
Joined
Jul 6, 2004
Messages
5,951
Dave, ummm....to the guy who created a system used by "most?" appraisers...what''s there to say.

We have HCA, which is completely open...and which, as it presents now, allows us to guess about the conforming to the new AGS standards.

How good is the guess? Not that many are qualified. You are pretty qualified. I have theorized...


Date: 12/20/2006 1:29:48 PM
Author: Regular Guy

The extent to which there is a good match, anyway, with a standard AGS0 profile with a given crown & pavilion angle, and a GIA one, given your satisfaction with the fact that GIA is the likely cert is a good question, better answered by an expert here, but not often done taken on, per se.
But, less than this, instead, now, the only help you are offering in principle is....send it to me for a direct measure, and this will give you some data.

Rock could as well say, send to to me for Gemex readout. Or, in other discussions...call me to let you know who to insure with.

Is it me, or are we having a bad day?

Then again, I''m not trying to earn a living.
 

RockDoc

Ideal_Rock
Joined
Aug 15, 2000
Messages
2,509
Date: 12/20/2006 1:49:52 PM
Author: oldminer
The industry is indeed a herd of sheep. Some are being led and a few are not. Some sheep are lost. I consider you and many other good guys as being too easily sold a bill of goods. The AGS Standard is strictly an in-house standard and not universally agreed upon. None of the tools which rely on ''calculation of measured parameters'' are going to become true standards. Direct measurement of performance will be the eventual model for a universal standard of diamond performance.
The AGS and Peter Yanzter are acting in good faith to better the industry and have been extremely open in their process. It is the process which is flawed and not their intentions, which we acknowledge are 100% tops. If the quality of their intentions were equalled by the questionable science behind the system, it would be far better. They have done a great job of marketing and convincing people, but only AGS uses the AGS system at this time. A real standard will be the same one all over the world. We''ve yet to agree on it yet.
Guess us sheep only have one thing to say.


BAAAAAAAAAAAAAAAAAAAAAAAAAAAAA !!!!!!!!!!!!!!

Rockdoc
 

diamondseeker2006

Super_Ideal_Rock
Premium
Joined
Jan 11, 2006
Messages
55,069
If the cert is GIA, try to stick with a crown angle between 34 and 35, and a 2 ct. stone should be close to 8.2mm in diameter. Look for a table between 54 and 57, and keep the depth 60-62. Can this stone be returned outright? Have you compared prices from reputable online vendors?

I''ll post a few excellent 2 ct. stones so you can compare to what you already have:

http://www.goodoldgold.com/diamond/359/

http://www.goodoldgold.com/diamond/361/

http://www.whiteflash.com/hearts_arrows/a-cut-above-h-a-cut-diamond-70656.htm

http://www.whiteflash.com/hearts_arrows/a-cut-above-h-a-cut-diamond-70735.htm
 
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