Should I be concerned with a girdle "very thin - thin 2%"?

[upgrade-me]

The GIA cert states "very thin - thin 2%". This is the 1st time I've noticed a GIA cert stating this. Should I be concerned? I'd just be setting the round diamond in a simple 4 prong setting. The diamond itself has got a great spread and rates 1.9 on HCA.

 

[upgrade-me]

Re: Should I be concerned with a girdle "very thin - thin 2%

I ran the #s in the HCA tool and got the following results:

Selected: 57.2% depth, 62% table, 32° crown angle, 41° pavilion angle
The result is for a symmetrical diamond with a medium girdle and very good polish.

Therefore, not sure why GIA cert states the very thin - thin comment...

 

[yssie]

Re: Should I be concerned with a girdle "very thin - thin 2%

There is no dichotomy here.

GIA:
GIA graders assign girdle min and max descriptions by eye, w/ a 10x loupe. In your case VTN-TN is the range of girdle thickness only in the sixteen valleys between the upper halves and lower girdle facets around the stone (this assignment doesn't account for chips, etc. that might affect small localised regions of girdle) The girdle thickness (here 2%) is an average of the eight bezel/pavilion main junction meets around the stone, expressed as a percentage of average diameter.
Excellent reading: http://www.diamondcut.gia.edu/pdfs/booklet_finish_culet_girdle.pdf (2009)

AGSL:
AGSL's description (thin, thick, etc.) reports maximum hill and minimum valley thickness around the stone, so an AGSL report might have a much larger indicated variation than a GIA report for the same stone.

What this means for you:
1. How big is this stone? Both min/max descriptions and girdle thickness are functions of stone diameter - a girdle that is 0.3mm by the ruler might be "thick" on a very small stone and "thin" on a larger stone.
2. A stone w/ a lower crown is at greater risk of chipping. 32deg raises "it's a legitimate concern" orange flags for me, but not "it's excessive, avoid it" red flags. It depends on stone size: 2% of 9mm is functionally much thicker (therefore less concerning) than 2% of 4.5mm, and on setting choice: a 4.5mm stone in an open four-prong setting is going to be better protected than a 9mm stone in an open four-prong setting.
3. The HCA is making assumptions about your stone's girdle to calculate the results, not calculating the results and then telling you more about your stone's girdle. Meaning... trust the report, not the HCA.

 

[upgrade-me]

Re: Should I be concerned with a girdle "very thin - thin 2%

Yssie - thanks for your reply. In response to:

What this means for you:
1. How big is this stone? Both min/max descriptions and girdle thickness are functions of stone diameter - a girdle that is 0.3mm by the ruler might be "thick" on a very small stone and "thin" on a larger stone.

The diamond is 2.35 carats with a spread of 8.8mm. According to your 2nd point then, because of the size of my stone, the very thin - thin comment is less concerning?

 

[RockyRacoon]

Re: Should I be concerned with a girdle "very thin - thin 2%

I ran the #s in the HCA tool and got the following results:

Selected: 57.2% depth, 62% table, 32° crown angle, 41° pavilion angle
The result is for a symmetrical diamond with a medium girdle and very good polish.

Therefore, not sure why GIA cert states the very thin - thin comment...

I think the confusion might come from the fact that 'The result is for a symmetrical diamond with a medium girdle and very good polish.' is an assumption made by the HCA, not a statement/assessment.

The 'result' it is referring to is explaining the results in assumed context.

When you think about it, how would plugging in angles result in an assessment of polish? That should cement the idea that these are assumptions.

Hope that helps!

 

[yssie]

Re: Should I be concerned with a girdle "very thin - thin 2%

Yssie - thanks for your reply. In response to:

What this means for you:
1. How big is this stone? Both min/max descriptions and girdle thickness are functions of stone diameter - a girdle that is 0.3mm by the ruler might be "thick" on a very small stone and "thin" on a larger stone.

The diamond is 2.35 carats with a spread of 8.8mm. According to your 2nd point then, because of the size of my stone, the very thin - thin comment is less concerning?

Yes. The chipping risk is still higher than ideal, given the shallow crown, but... you aren't walking around with a ticking bomb.

Would you consider an 8-prong setting, or a bezel? These would mitigate the chipping risk immensely.

 

[diamondseeker2006]

Re: Should I be concerned with a girdle "very thin - thin 2%

There are so many diamonds out there with nice 34-35 degree crown angles, so why not just keep looking? Aside from chipping risk, I don't think relatively flat crowns (especially when the tables are large) look so good in the profile view of the stone.

 

[upgrade-me]

Re: Should I be concerned with a girdle "very thin - thin 2%

Thanks for everyone's feedback. What was appealing was the wide spread but based on people's comments, I'll pass and continue to look for something better.