Questions about girdle thickness

[Clear Winner]

Hi again,
I was hoping someone could help me learn a little more about girdle thickness.

-Is a medium girdle what most people would look for when purchasing a high quality diamond with Ideal or Excellent Cut?

-Would I be able to notice a difference in any way between a Medium and a Medium to Slightly Thick sized girdle with the naked eye?

-If the girdle does range between two different thicknesses does that not mean that the table doesn’t run completely parallel to the girdle? If that is the case then wouldn't that affect the overall symmetry and performance of the diamond?

Thanks
CW

 

[yssie]

Hi again,
I was hoping someone could help me learn a little more about girdle thickness.

-Is a medium girdle what most people would look for when purchasing a high quality diamond with Ideal or Excellent Cut?
Would look for anything from thin-slthk. Vthin can be fine too if it's just a small part of the girdle or a part that can be protected by setting arrangement, but you want a professional to look over the stone. Avoid exthin, and vthin if crown is shallow and stone is smaller. I would avoid thick+ b/c means weight is hiding and not contributing to spread.

-Would I be able to notice a difference in any way between a Medium and a Medium to Slightly Thick sized girdle with the naked eye?
Like any other measurement girdle is reported in ranges.. in general no, unless you are looking for it and have some basis for comparison (ie. two stones of the same size w/ different known girdle measurements). An overly thick girdle can be unsightly to someone who is looking for it - vthk, exthk, even thk if larger stone.

-If the girdle does range between two different thicknesses does that not mean that the table doesn’t run completely parallel to the girdle? If that is the case then wouldn't that affect the overall symmetry and performance of the diamond?
extreme variations - thn to thk, say, would raise some eyebrows but reported measurement that spans a one or two ranges is quite normal. Girdle is measured in thickest and thinnest areas (thickest and thinnest valleys if GIA, thickest and thinnest all 'round the stone if AGS so AGS reported girdle variance is often broader in range), not as an average - the thickest and thinnest areas tell you nothing about the average or median by definition. Girdle measurement threadsGIA & AGS

Thanks
CW

 

[John P]

Hi again,
I was hoping someone could help me learn a little more about girdle thickness.

-Is a medium girdle what most people would look for when purchasing a high quality diamond with Ideal or Excellent Cut?

-Would I be able to notice a difference in any way between a Medium and a Medium to Slightly Thick sized girdle with the naked eye?

-If the girdle does range between two different thicknesses does that not mean that the table doesn’t run completely parallel to the girdle? If that is the case then wouldn't that affect the overall symmetry and performance of the diamond?

Only in extreme cases, and they would be penalized appropriately.

The goal for a diamond's girdle is to have enough thickness to prevent chipping but not so much that it adds weight needlessly. If the description = Thin, Medium, Slightly Thick (or any combo of the three) it meets that goal with AGSL/GIA.

Thin, med & slightly thick girdles are all durable and hide no appreciable weight. The med and stk range are best for tension settings. A girdle at the thin side of thin may get you a tiny bit more spread.

Even if one descriptor is outside (vtn-med for example) it may not necessarily be a deal-killer... Further examination of the specific diamond will reveal what that ‘outer’ descriptor implies. It could indeed be enough to disqualify it, or it could be a single tiny position that won't be a problem. It’s a stone by stone call.

Remember girdle thickess is a range: One girdle described as “thin” may be a micron away from medium. Another “thin” may be close to very thin. Both are perfectly acceptable, but the hair-from-medium "thin" would be a better candidate for certain settings. The AGSL range for thin is wider than the ranges for medium & slightly thick combined, so an abundance of well-made diamonds will have thin in their girdle description.

More info & photos in this prior thread:
https://www.pricescope.com/community/threads/girdles.66614/

 

[Clear Winner]

Thanks for all the info. but I'm still a bit confused as to how GIA measures the girdle thickness. (I'm probably buying a GIA graded diamond)

-When a GIA cert says Medium-slightly Thick 4.0% what does the 4.0% represent? The average thickness of all 16 valleys?

-Could the peeks of that same diamond's girdle then be all over the place? Some much higher than others? or just really big? if they arn't measures at all?

-hmmm..... so I guess optimally I'd be looking for GIA thin but almost Medium or Thin to Medium to get a thick enough girdle that I don't need to worry about it chipping and not thick enough to take away needless carat weight? 2.0-2.75 area?

Thanks
CW

 

[John P]

-Could the peeks of that same diamond's girdle then be all over the place? Some much higher than others? or just really big? if they arn't measures at all?

Not likely without serious influence on the upper/lower halves, which would result in a brillianteering deduction.

so I guess optimally I'd be looking for GIA thin but almost Medium or Thin to Medium to get a thick enough girdle that I don't need to worry about it chipping and not thick enough to take away needless carat weight? 2.0-2.75 area?

I suggest that you may be over-thinking it. Any girdle (round brilliant) graded thin, medium, slightly-thick - or any combination of those descriptions - will be fine.

 

[Clear Winner]

Thanks a lot John Pollard, just making sure I wasn't overlooking something.

 

[John P]

Thanks a lot John Pollard, just making sure I wasn't overlooking something.

No worries. Good luck in your hunt!