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real diamond master set OR stabilized CZ set?
Diamonds 73%  73%  [ 11 ]
stabilized cubic zirconia 27%  27%  [ 4 ]
Total votes : 15
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 Post subject: Re: diamond color grading master set!!!!
PostPosted: Sun Oct 21, 2012 12:35 pm 
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Barbara,
it would be good to have time for that, i that many gemologists owing a diamond series followed that path........over the years.
BUT.what about pour law?? could we write: "diamond color must be graded with a diamond master set and you have 3 yrs from now to assemble one"..... :lol:
ciao
albé

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 Post subject: Re: diamond color grading master set!!!!
PostPosted: Mon Oct 22, 2012 2:08 pm 
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when it comes to masterstones it can be problematic, i think the IDC masterstones are slightly different than GIA's. thats why we get different grades comparing the same stone with HRD and GIA's report but this does not happen often. we sometimes get different color grades when we send the same stone to GIA twice or more! (even two grades!!) so even GIA can make mistake!

as far as i know there were two generation of masterstones and The masterstones must comply with the following requirements:

1- Round Brilliant- Shapes only
2- weight: larger than 0.70 ct but second generation not smaller than 0.30 ct.
3- proportions: vg
table diameter: 60 to 66%
crown height: 11 to 14%
girdle thickness: smaller than 3%
pavilion depth: 42 to 45%
4- clarity: vs2 or better, free of colored or black inclusions and structure phenomena causing color effects
5- girdles: bruted, faceted or polished girdles (the nature of the girdles must be the
same within 1 set of masterstones)
6- fluorescence: nil or slight (None or Faint)
7- color: yellow hues or “yellow series” only (another problem with masterstones is the color deviation or as they say in trade "the Shades/overtone")

i think if one orders diamonds which meets the required standards it would be cheaper. of course from a reliable source.

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 Post subject: Re: diamond color grading master set!!!!
PostPosted: Mon Aug 21, 2017 10:07 pm 
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Hello all. The last place I knew was still in the business of offering masterstones has recently decided to leave the business of building sets of Master Color Comparison sets. Gary W. Wright has decided to liquidate what he has in inventory as single stones and sets and not submit any diamonds to AGS to be qualified as a masterstone.

I think with the newest introduction of CVD diamonds, we may soon see those being qualified as masterstones. After all, wouldn't they be much more qualified than CZ?


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 Post subject: Re: diamond color grading master set!!!!
PostPosted: Tue Aug 22, 2017 12:33 am 
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Certainly, theoretically, a fab idea with the synthetics.

But when you consider most masters are 0.25-0.35ct.....it is actually the price of grading which adds most of cost to the final master set.
Even with synthetics, there will be a lot of rejects, adding to skyrocketing lab fees.

I'm not 100% sure that a synthetic master set will be substantially cheaper.


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 Post subject: Re: diamond color grading master set!!!!
PostPosted: Wed Aug 01, 2018 8:25 am 
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Barbra Voltaire wrote:
Certainly, theoretically, a fab idea with the synthetics.

But when you consider most masters are 0.25-0.35ct.....it is actually the price of grading which adds most of cost to the final master set.
Even with synthetics, there will be a lot of rejects, adding to skyrocketing lab fees.

I'm not 100% sure that a synthetic master set will be substantially cheaper.

i was referring to this topic that i saw your last post :) it seems like now that lab grown diamonds are cheap now so one can consider using Synthetics at a reasonable cost less than natural diamonds set

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Last edited by roshanravan on Wed Aug 01, 2018 8:50 am, edited 1 time in total.

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 Post subject: Re: diamond color grading master set!!!!
PostPosted: Wed Aug 01, 2018 8:47 am 
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i dont think it would be so easy, colorless to near-colorless synth are all IIa, the "as grown" material feature colors which have nothing in common with the cape series.
OTOH, if you decide to let single nitrogen work there, u will end up with far more saturated yellows.
all in all i don't think it will be possible, at least for now....
my 2c only... :wink:

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 Post subject: Re: diamond color grading master set!!!!
PostPosted: Wed Aug 01, 2018 8:52 am 
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Alberto wrote:
i dont think it would be so easy, colorless to near-colorless synth are all IIa, the "as grown" material feature colors which have nothing in common with the cape series.
OTOH, if you decide to let single nitrogen work there, u will end up with far more saturated yellows.
all in all i don't think it will be possible, at least for now....
my 2c only... :wink:

you are right, maybe using lab grown only for high colors?

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 Post subject: Re: diamond color grading master set!!!!
PostPosted: Wed Aug 01, 2018 8:54 am 
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still u will have weird greyish, brownish overtones....not really suitable for color grading.....

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 Post subject: Re: diamond color grading master set!!!!
PostPosted: Wed Aug 01, 2018 10:09 am 
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I have spoken directly to some De Beers (Element Six) researches on this subject. Basically they have tried and are in agreement with Alberto. The color casts are too different to make acceptable master sets.

I find that CZ being brown/grey tinted have this same issue. They get close, but not close enough. Useful for educating, but not actual grading. Working with one of the manufacturers I was finally able to come up with a set that can consistently be placed in the proper order, so a good relative scale only.


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 Post subject: Re: diamond color grading master set!!!!
PostPosted: Wed Aug 01, 2018 10:28 am 
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1bwana1 wrote:
I have spoken directly to some De Beers (Element Six) researches on this subject. Basically they have tried and are in agreement with Alberto. The color casts are too different to make acceptable master sets.


this is logic. the typical cape series yellow comes from nitrogen aggregates and in IIa you do not have any....

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I find that CZ being brown/grey tinted have this same issue. They get close, but not close enough. Useful for educating, but not actual grading. Working with one of the manufacturers I was finally able to come up with a set that can consistently be placed in the proper order, so a good relative scale only.


there are manufacturers of CZ set which produce really consistent stuff, but those are expensive, not really the 200-300$ a set stuff....

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