How Could it be a "Dud"?!

[Lynn B]

I have been having (very interesting!) ongoing conversations with a co-worker about diamonds. Today we were discussing so-called "duds" and I told her that it is imperative to see a diamond with your own eyes, because I have read that "duds" can be found among even "ideal cut" stones. She then asked me a question that really made me think. I honestly don''t know the answer!

Could a diamond be AGS-0 (or GIA/other lab "equivalent"), all angles within "ideal" parameters, H & A, 1-A AGA grading score, 2 or less on the HCA, good Idealscope image, high color and clarity... and STILL be a "dud"?! And if so, how could that possibly be?!?

I do know that different diamonds all meeting those criteria may well look "different", and beauty is always in the eye of the beholder... but she is talking about true "duds". Is that possible?

Thanks!
Lynn

 

[wanderlost]

very possible... look at the HCA cut guide (and the box that is marked AGS 0).... the old steep & deep (the top most part of that box) you will notice is not red, orange or even yellow... but green (and prehaps a little blue)..... these stones look DEAD. A local B&M told me they had a stone that was the best of the best & had it shipped in. Right away I could tell this did not have much light return.... looked dark & unspectacular... after looking at the Sarin & plugging in the numbers to the HCA, this "AGS 000" stone ended up scoring a 3.8!

There are definately these stones out there.... that's why it's so important to see them in person.


[Edited: Oops.... sorry.... didn't read your post closely enough.... HCA<2 duds?.... I'm sure it's possible...(though rare)... inclusion(s) could really affect the amount of light coming back to you, also wierd features like a large faceted culet or an ex. thick girdle could potentially ruin a perfectly good stone (which I don't know if the HCA calc. takes into count girdle thickness (other than ex. thin)).....]

 

[aljdewey]

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On 8/17/2004 3:29:21 PM Lynn B wrote:

Today we were discussing so-called 'duds' and I told her that it is imperative to see a diamond with your own eyes, because I have read that 'duds' can be found among even 'ideal cut' stones.

Could a diamond be AGS-0 (or GIA/other lab 'equivalent'), all angles within 'ideal' parameters, H & A, 1-A AGA grading score, 2 or less on the HCA, good Idealscope image, high color and clarity... and STILL be a 'dud'?! And if so, how could that possibly be?!?

Thanks!
Lynn ----------------

The key to the question is this..."can an 'ideal cut' diamond be a dud." A diamond doesn't have to perform well on all of those tests to be called an "ideal cut", and that's where the answer lies.

It's probably highly unlikely that a diamond could perform well in ALL of those areas (AGA rank, HCA, all the -scope tests, AGS cut grade) and still be a dud, but anything is potentially possible.

The more likely scenario is that a diamond is considered or defined "ideal" simply because it achieves AGS0. However, the AGS0 gives only RANGES of optimal parameters but doesn't note that it matters how those are paired together. A diamond with a 34.3 and 40.7 relationship will likely perform quite well. A diamond with a 35.7 crown/41.2 pavilion will likely perform less well...these angles aren't meant to pair together.

 

[Rank Amateur]

Once you have the IdealScope view it seems to me that the chances for a dud are greatly reduced.

If you don't have an IS view, poor symmetry/alignment of opposing pavillion facets could make a mess of the light return (which the HCA does not predict), but I'm guessing the chances are 1 in 100 where this is significant enough that an amateur would notice it.

 

[Rhino]

If you drop me an email I'll link you to some examples of AGS "0" duds.

 

[Garry H (Cut Nut)]

It could be a dud if the stone was cloudy / not so transperant. There is no grading measure for that - but diamonds that have been graded say SI2, but have very few inclusions (say VS2) are possible contenders.
Also over blue fluoro stones that appear oily - but this is less than 0.3%.

 

[valeria101]

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On 8/17/2004 3:29:21 PM Lynn B wrote:



Could a diamond be AGS-0 (or GIA/other lab 'equivalent'), all angles within 'ideal' parameters, H & A, 1-A AGA grading score, 2 or less on the HCA, good Idealscope image, high color and clarity... and STILL be a 'dud'?! And if so, how could that possibly be?!?

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Taken one by one, each of these criteria is not absolutely conclusive - acording to the PS wisdom I ma aware of. So:

#1. we know that the AGS0 standard still leaves room for error,

#2. The angles can be all "ideal" but they do not take into account those monir facets which, rarely ( "rare" is key word, I think), can be way off the norm and get you an unexpected dissapointment.

#3 the Ideal Scope gives detail about light return, bt it is hard to read about fire and contrast on it. This test would get the AGS0 and HCA misses out of the race, but perhaps miss fine details.

#4. color and clarity need to get really off the beaten track to make a greta cut "ugly". I too have in mind the exceptions Garry mentions, and a particular VS2/SI1 (my guess of grade, so not official) diamond with the clarity grade based solely on internal graining I saw yesterday

leaving accidents in the #4 range aside, I would not call a diamond that pases all these hurdles a "dude".

This is about all I know.

 

[Lynn B]

Thanks, everyone, for your input. Interesting thread!

I am waiting to look at Jonathon's examples of AGS-0 "duds"... and I will be curious to see those stones' Idealscopes plus how they "score" in the HCA, AGA, etc.

I'm getting the idea, though, that it is probably safe to assume that (with VERY RARE and unusual exception -- thanks, Garry!) a stone meeting ALL the criteria (in the original post) could probably NOT be a dud.

Right?!

Thanks,
Lynn

 

[wanderlost]

I'd be very interested in seeing a stone that 'passed' all those criteria and was still a dud.... would definately be marketable to Ripley's