A Diamond''s girdle – What to look for?

[strmrdr]

Some of these questions have been answered at various times but it would be nice to get them in one place.

How does the girdle affect the appearance of a diamond?

How thin is too thin?
What are the problems with a too thin girdle?

How thick is too thick?
What are the problems with it being too thick?

How do the ratings i.e.: med to sl thick relate to percentages?

Is there a different standard on what is acceptable for different shapes of diamonds?

Is an inclusion near the girdle a problem?
Is it better to put it under a prong or near one?

What questions should be asked of a vendor about it when considering a diamond?

 

[pqcollectibles]

I found some of your answers, Strm. And also found some additional information.

From this Price Scope thread posted by Leonid, I got the Grading Lab thickness ratings.

Different labs use different systems for girdle thickness: GIA measures mm while AGS %:

GIA
Extremely thin 0.00 - 0.08 mm
Very thin 0.08 - 0.12 mm
Thin 0.12 - 0.15 mm
Medium 0.15 - 0.20 mm
Slightly thick 0.20 - 0.23 mm
Thick 0.23 - 0.33 mm
Very thick 0.33 - 0.40 mm
Extremely Thick: greater than 0.40 millimeters

AGS
Very thin 0.091 - 0.50%
Thin 0.51 - 1.2%
Medium 1.21 - 1.7%
Slightly thick 1.71 - 2.95%
Thick 2.96 - 4.2%
Very thick 4.21 - 5.7%
Extremely Thick: >= 5.71 %

HRD
Ex.Thin 0.0 - 0.5%
Very Thin 0.5 - 1.5%
Thin 1.5 - 2.5%
Medium 2.5 - 4.5%
Sl.Thick 4.5 - 6.0%
Thick 6.0 - 7.5%
Very Thick 7.5 - 8.0%
Ex. Thick 8.0 - 100%


How thin is too thin?
https://www.pricescope.com/community/threads/girdle-thickness.4372/

Problems with a thin girdle?
https://www.pricescope.com/community/threads/extremely-thin-and-very-thin-girdles.5603/

A discussion on inclusions near the girdle:
https://www.pricescope.com/community/threads/diamond-chipping-on-inclusion.4123/

An interesting discussion involving the girdle and setting/resizing a ring:
https://www.pricescope.com/community/threads/chipping-a-diamond.4840/

 

[strmrdr]

Thank you pq :}

Its a great start.

 

[fire&ice]

People can have many different views on what is acceptable to *them*. It depends on the setting as well. And whether it's set in a pendant, ring, e.r, etc.

The girdle is a place for excess unseen waste. Flip side of that is that a bigger girdle may protect the stone.

I would avoid extremely thin, especially on princess corners, & thick/extremely thick. I would call into question a stone that also goes from one extreme to the other.

Other than that, it's just one more thing that goes into the issue of selecting a stone. BTW, I just purchased a stone that had a small feather extend to the girdle. Normally, I would freak; but, the stone had everything else going for it & was being set into earrings. Unless you are prepared to pay the premium for a colorless near perfect stone, you will always have an issue about something. And, even in those stones, the issue of cut may be a factor.

 

[strmrdr]

btt