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Sarin crown angle measurment and GIA differ greatly - why

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cm

Rough_Rock
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Aug 27, 2008
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GIA gives the crown angle as 34.5
The sarin report says the crown angle is 35.7 (avg) with a range of 34.6 - 38.6

How can it be possible that the Sarin report shows that the lowest crown angle isn''t even 34.5. Which measurment should I trust? Is it possible the Sarin report was not done correctly?

Additionally, the GIA cert has the stone as .01 heavier than the Sarin report. I was advised the GIA weight is more accurate.

All of the other details seem to agree withine reason. For instance sarin table 54.7% GIA table 55%.
 
bad sarin scan is the most likely explanation.

Its not the same diamond is another possibility.
 
Date: 9/3/2008 12:31:31 PM
Author:cm

GIA gives the crown angle as 34.5
The sarin report says the crown angle is 35.7 (avg) with a range of 34.6 - 38.6
Edited: I misread the highlighted. Yes, probably a bad scan of crown angle.


Additionally, the GIA cert has the stone as .01 heavier than the Sarin report. I was advised the GIA weight is more accurate.
The GIA report is usually considered the "document of authority." A discrepancy like this is minute. Sometimes scales can differ; re-calibration of a good scale will usually make it accurate to the hundredth of a carat.


All of the other details seem to agree withine reason. For instance sarin table 54.7% GIA table 55%.
GIA reports table% in whole numbers so no problem there.
 
Thank you.
 
The Sarin machine doesn’t weigh the stone. It’s estimating the weight by knowing the volume and the density and doing a bit of math. GIA does it with a scale, which is a much better approach.

Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Jewelry Appraisals in Denver
 
I thought GIA rounded their crown and pavillion angles? Wouldn''t that account for the differences?
 
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