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History of a stone, AGS in 2005, GIA in 2015

nikolajkarpov

Rough_Rock
Joined
Aug 5, 2016
Messages
4
Hi,

Bought this stone (Round, 2.007, H, VS1):

AGS - 6687708
GIA - 2171269039

screen_shot_2016-08-05_at_11.png screen_shot_2016-08-05_at_11_0.png

So looks like stone was originally graded by AGS in 2005 and sold. After some time it got back to the market, probably it was polished from the sides since 3 things changed:

Crown Angle: 34.2 -> 34.5
Depth: 55.9 -> 56
Total Depth: 62.1 -> 62.3

Also however it was graded by AGS as AGS Ideal 0, GIA graded it as Excellent, Excellent, Very Good.

What do you guys think?
 

John Pollard

Ideal_Rock
Trade
Joined
May 1, 2008
Messages
3,559
Cool question.

No proportions were altered. Scan technology isn't perfect. Given error is circa ± 0.02 mm linear. GIA scanned the depth at 5.01 mm compared to AGS' older scan of 5.00 mm. Nothing grew it 0.01 deeper over time of course (wouldn't that be nice). GIA also rounds to nearest 0.5° on crown angle, so 34.5 is likely 34.3 or 34.4 rounded up. All within tolerance. All makes sense.

Appears to be some wear and tear along the way. Symmetry went from AGS Ideal to GIA VG. This indicates some impairment to facet lines, meet points or junctions in the interim.
 

nikolajkarpov

Rough_Rock
Joined
Aug 5, 2016
Messages
4
Thank you John, makes perfect sense.

One more question if you don't mind:

1. If you have to judge the price based on the certificates, I assume price based on GIA cert would be lower for 2-4k because of Symmetry and Fluorescence (from medium to strong)?

The reason I'm asking is that I bought it based on AGS cert, but when received I've found GIA inscription which pulled more interesting details on a current state and I'm not sure it's worth what I paid for it.

diamond3_1.png
diamond2_3.png
diamond1_8.png

Thank you in advance!
 

diamondseeker2006

Super_Ideal_Rock
Premium
Joined
Jan 11, 2006
Messages
55,630
Are you within your return period? I'd want price based on the most recent grading definitely.
 

diamondseeker2006

Super_Ideal_Rock
Premium
Joined
Jan 11, 2006
Messages
55,630
nikolajkarpov|1470586608|4063309 said:
Yes, I can return it. I'll get the appraisal on Tue, hope this will give some estimate.
Just be forewarned that many appraisals have inflated value. So your main objective would be confirmation of the GIA grading. Determine pricing based on stones with the same specs. We can help you if you want.
 
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