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GIA report vs AGL report

catforfish

Rough_Rock
Joined
Feb 27, 2016
Messages
2
Good Morning,

I recently purchased an "unheated ruby". The seller also provided GIA report which shows the stone is unheated nature ruby (I can find the report in GIA online system by report number, so I guess the report is authentic?). Then I sent the stone to AGL for recheck just in case. However, the AGL report tells another story. It says that the stone is heated sapphire. AGL told me that the stone can not be called ruby because the color is too muddy since the stone has a brownish tone (while the GIA report only says the color is purplish red), and the treatment difference may come from low heat treatment that has not been detected by GIA. In this case, I think I will trust AGL's judgement, but still there are some questions in my mind:
1. I have compared the size, weight, shape information from the two reports, it seems they match except 0.01mm difference in size. But is it possible for the seller to provide me another stone (with identical shape, size, weight)'s report?
2. If that is not possible, should I contact GIA for recheck?

Thanks a lot!

Yun

agl_report.jpg

gia_22.jpg

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Michael_E

Brilliant_Rock
Trade
Joined
Nov 19, 2003
Messages
1,290
catforfish|1456590614|3996591 said:
Then I sent the stone to AGL for recheck just in case. However, the AGL report tells another story. It says that the stone is heated sapphire. AGL told me that the stone can not be called ruby because the color is too muddy since the stone has a brownish tone (while the GIA report only says the color is purplish red), and the treatment difference may come from low heat treatment that has not been detected by GIA.
The AGL is most likely using a different method of determining heating than the GIA. I'm not sure what "low heat" means since I've never heard of anyone using actual temperature numbers for this, but you might want to ask the AGL what that means, just for your own curiosity.
Calling a reddish sapphire a ruby has a long history of contention and there still isn't a widely agreed upon cutoff point in the color spectrum beyond which a gem is no longer a ruby. Basically if the stone has a fragrance of red in it, then it's a ruby...if you're the seller. If I was buying that I would question the buyers truthfulness in calling that a ruby. Does it look like a ruby to you?

1. I have compared the size, weight, shape information from the two reports, it seems they match except 0.01mm difference in size. But is it possible for the seller to provide me another stone (with identical shape, size, weight)'s report?
.01mm is less than the accuracy specs for most calipers and so this number difference could be due to the different calibration of the measuring tools each lab is using. It's not uncommon to have slightly different numbers or even colors, (since each lab may be using slightly different spectral lighting).

2. If that is not possible, should I contact GIA for recheck?
You could try it, but if the AGL is using different methods for determining heat treatment, then you may still get different results.
 

catforfish

Rough_Rock
Joined
Feb 27, 2016
Messages
2
Hi, Michael,

Thanks so much for the reply! Yes, I do like the stone, and it does look like a ruby to me. Probably I should just let it go.
Also, I noticed that the GIA report is from GIA Bankok. I am wondering if there is any quality difference between GIA Bankok and GIA New York? Thanks a lot for the help!
 

chrono

Super_Ideal_Rock
Premium
Joined
Apr 22, 2004
Messages
37,365
AGL has been able to detect treatment that GIA missed on several occasions, but just in case, I would present this case to both AGL and GIA to get their opinion on it. The size discrepancy is minute (and to be expected) and thus negligible.

To my eye, the stone is too muddy to be considered a ruby, and I noticed that the Asian based labs tend to be more generous in their labeling a sapphire with even a little red a ruby.
 
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