GIA rounding question

[teobdl]

Could someone please clarify the issue of GIA rounding (for the HCA measures, as well as minor facets if possible)? And for comparison, how does GIA rounding differ from AGS rounding in the relevant measures?

The reason for my question is a number of threads of late have mentioned a GIA rounding issue (almost as if it's going to ruin the industry!). Has it changed recently?

 

[c-k]

Could someone please clarify the issue of GIA rounding (for the HCA measures, as well as minor facets if possible)? And for comparison, how does GIA rounding differ from AGS rounding in the relevant measures?

The reason for my question is a number of threads of late have mentioned a GIA rounding issue (almost as if it's going to ruin the industry!). Has it changed recently?

There may be several with much more expertise than me, but for a consumer my take is this..

GIA rounds the specs on the lab reports, so the numbers may be off, studies have stated the amount of rounding does not have any visual effect. But it makes it hard to compare one GIA stone to another GIA stone. The broad range of their cut grade puts many diamonds into the Excellent cut grade, but it really requires much more information to know if all of these are created equal.

 

[Christina...]

You may find this thread helpful.
[URL='https://www.pricescope.com/community/threads/consumer-advisory-gia-cut-grade-rounding-problems.39401/']https://www.pricescope.com/community/threads/consumer-advisory-gia-cut-grade-rounding-problems.39401/[/URL]

And this article by Jonathon explaining GIAs cut grade system..
http://www.goodoldgold.com/content.php?c=58


GIA reports round the given averages. So when you see '34.5 degrees' the actual average was rounded to the nearest 0.5 degree, meaning the real number could be 34.3-34.7 And where you see 75% it was rounded to nearest 5%, so the actual number could be 73-77%.

Edited

Oops sorry, I linked the wrong thread...I wanted to link this one not the first one.
[URL='https://www.pricescope.com/community/threads/how-significant-are-the-star-facets-and-lower-girdles-info.31985/']https://www.pricescope.com/community/threads/how-significant-are-the-star-facets-and-lower-girdles-info.31985/[/URL]