Question for the experts: Girdle plots

[strmrdr]

How common is it for them to look this far off?
Is the girdle another item we need to get the vendors to double check when they are "eyeballing" the diamonds for us or are the plots usualy more trustworthy?

This a sister thread to this one but I felt it needed its own thread.

https://www.pricescope.com/community/threads/tail-of-a-princess%E2%80%99s-girdle.14798/

Thank you Brian @ whiteflash for the photo.

 

[niceice]

Excellent samples Strmrdr with special thanks to Brian at WhiteFlash.com for providing them!

Is this something that reputable vendors should be checking? Of course! And the first clue that something is amiss is the girdle side profile analysis provided by the OGI / Sarin machines during the initial evaluation process for proportions... And reputable dealers should be doing a visual inspection of the girdle during their evaluation process as well... It's the "virtual" dealers that you're going to have to watch on this one because (1) they don't see what they sell and (2) we've noticed that the calibration of many of the machines used by the various cutters are not so precise - we see things like a diamond offered to us as having a 34.5 degree crown angle that is really 33.7 degrees when run on our machine... How do we know that our machine is "on" and theirs is "off"? Simple enough. All of the other measurements on their proportions analysis are off from what was provided by the lab on the stone and ours are not... Make sense? So when you're considering a "virtual" diamond from a dealer who drop ships, make sure that the proportions analysis offered with the stone is a really close match to what is stated by the lab... i.e. if the GIA says that the total depth of the stone is 60.2% and the OGI / Sarin analysis says that it's 60.3% that's close enough to be considered accurate, but if it says something like 60.8% you've got the potential for total inaccuracy.

 

[strmrdr]

thanks R/T