VG GIA cut grade but scores 1.0 HCA, 1B AGA/NAJA cut class

[Jayebe]

Hi everyone,

I found this diamond at a local store's inventory and wonder if it's worth going in to take a look.
The price is reasonable, 1.70 ct, G color, SI1 for $17400 Canadian dollar.

GIA certificate#5151719465, I'm also attaching pdf file to this topic.
Cut grade is VERY GOOD, based on my research on this forum I should always get the best cut possible so I wouldn't normally consider this diamond. However, when I entered the #s into HCA tool and AGA/NAJA cut grade tool, I got great scores. 1.0XXXV HCA and 1B.
How is this possible? do you think GIA made a mistake of grading the cut? Or should I just stick with GIA XXX and AGS 000.

Thanks for your help in advance.

 

[teobdl]

Re: VG GIA cut grade but scores 1.0 HCA, 1B AGA/NAJA cut cla

They did not make a mistake. You'd probably need someone like John Pollard or Garry Holloway to chime in, but the VG is probably due to the thick girdle.

I'd be interested to see an idealscope on it. Can you get this image?

 

[Jayebe]

Re: VG GIA cut grade but scores 1.0 HCA, 1B AGA/NAJA cut cla

Unfortunately they don' t have Ideal scope image available, asked me to come in and take a look myself.
Didn't know medium to thick girdle can impact cut grade. thank you for the info!

 

[John P]

Re: VG GIA cut grade but scores 1.0 HCA, 1B AGA/NAJA cut cla

They did not make a mistake. You'd probably need someone like John Pollard or Garry Holloway to chime in, but the VG is probably due to the thick girdle.

No need for me or Garry here Teobdl; you nailed it. GIA has penalized the diamond because it's a 1.70 that faces up like a well-cut diamond of 1.57-1.60ct. It's due to the girdle running to Thick... AGS would penalize it for the same reason.

In terms of proportions it would be GIA EX minus the TK girdle. It's also a potential AGS 0 light performance candidate, depending on what the actual numbers are. We can't know due to GIA's practice of rounding.

If the cut consistency is good the light performance is probably nice. But without more images and data we can't know, nor can we know the level of optical precision or other cut details which influence ultimate trade value.

Whatever the fine details: This diamond should be priced as a 1.60ct rather than a 1.70.

 

[Garry H (Cut Nut)]

Re: VG GIA cut grade but scores 1.0 HCA, 1B AGA/NAJA cut cla

The numbers in HCA are my opinion.
I cant open the file as i am on a loaner computer at present. But from what John wrote, it probably is a keeper based on light performance - the HCA will give you a Spread rating.
So price it as if it were a about the weight John gave you, and you may still be ahead

 

[diamondseeker2006]

Re: VG GIA cut grade but scores 1.0 HCA, 1B AGA/NAJA cut cla

Here is a price comp for you. This one is AGS Ideal cut but is a little on the deep side, so it faces up just a tiny bit larger than the one you are looking at. Not sure what your dollar is to ours, but this one is $16,041 US with pricescope/wire pmt. discounts.

http://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-3016703.htm

 

[John P]

Re: VG GIA cut grade but scores 1.0 HCA, 1B AGA/NAJA cut cla

Here is a price comp for you. This one is AGS Ideal cut but is a little on the deep side, so it faces up just a tiny bit larger than the one you are looking at. Not sure what your dollar is to ours, but this one is $16,041 US with pricescope/wire pmt. discounts.

http://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-3016703.htm

Hi DS.

A couple of observations: I'd first note that the significant additional information in the link you provided is worth a premium. We can clearly see cut-consistency and optical precision that's notably above average. Second, the diamond in your link has AGS Ideal polish and symmetry, which answer to stricter standards than GIA EX requirements, which is certainly worth something as the diamond it's being compared to has VG symmetry. A subtext there is that VG (and lower) symmetry may indicate lesser cut-consistency and optical precision, as a by-product of sloppier production. Finally, in the OP's diamond twinning wisps are the grade-setting inclusions. Those are structural distortions which (like feathers) I'd want to know more-about. Of course, I'd want to know about the crystals in the linked diamond too (or any inclusions for that matter) but twinning wisps can *sometimes* be indicators of strain/durability issues, whereas crystals (even if visible) are benign.

What I'm saying is; based on the information at-hand the diamond you linked might be somewhat more valuable than the other.