How bad is a "thick" girdle?

[diamanda]

Obviously I''m not a very experienced diamond critic. If all the other numbers are good, how much would a med-thick or thick girdle affect the overall quality?

 

[the tree sees]

Diamanda,

I think these two pages should be on point:

Girdle Thickness

Fish-Eye

I''ll leave it to the experts to elaborate. I just repeat what I read/hear.

Best,

 

[Lorelei]

Date: 6/17/2009 9:48:31 PM
Author:diamanda
Obviously I''m not a very experienced diamond critic. If all the other numbers are good, how much would a med-thick or thick girdle affect the overall quality?

Jason has given you some excellent links!

Basically a med - thick, thick girdle can waste weight in some cases. They key is how much of the girdle is affected by the thick part, if it is just a small portion then it might be fine, more and it can waste weight which in turn can sometimes make a diamond look a little small for the weight. An expert vendor will be able to advise, and it is best to evaluate on a case by case basis.

 

[bowral1]

What is the shape of the diamond you are wanting to know? I only ask because a lot of cushions have thick girdles. There was some discussion (blogs) on cushion girdle thickness if you do a search on this website.

 

[Garry H (Cut Nut)]

Hi Jason,

Girdle thickness has very little impact on a diamonds sparkle or beauty. Thisk girdles ensure the stone will be very hard to break, and thin is risky in rings.

But as Lorelie mentiond - you get a smaller diamond. /but if the price is the equivalent of a diamond with that spread then alls good.

consider this

a 6.1MM 1ct diamond is about 3 or 4mm smaller than we would prefer - it has the ideal spread of a 0.90ct stone. But if the table crown and pav are all good, and the stone is only suffering a very or extremly thick girdle then you can have the right to tell your girlfriend she has a ONE CARAT diamond that will sparkle nicely but side by side appear the same as a 0.90ct stone.

Now, should you pay a little more for this benefit? The Cut Group i work with think a fair thing would be about a 50% price gain for the diamond cutter and you should get your smaller but heavy stone cheaper. Win Win.

This is a theory that we will put into practice in the case of fancy cuts which are often small for their weight.


Now this is technically moving now into a thread-jack:

Value of Next Diamond = Value of same size of RBC X (spread factor)a X (quality factor)b
Value of RBC = Price per Ct X size in Ct
Price of Next Diamond = Value of ND / size in Ct
Spread Factor = {(100+spread%)/100}
Quality Factor = 1 if stone performs same or a bit better than ideal RBC
a = quotient for Spread factor = 0.5 (50% benefit for consumer and 50% for manufacturer)
b = quotient for quality factor = We will start with 1.0 if the quality performance is better or equal to
ideal RBC

Now that''s simple isn''t it?

 

[Richard Sherwood]

If all the other proportions are in sync, a thick girdle usually has no detrimental effect to the visual presentation of the diamond, other than making it look a little smaller than if it were a thinner girdle. The "ideal" range is from thin to slightly thick, for comparison purposes.

 

[Kaleigh]

Can I sneak a question in here?? Due to girdle thickness. I read all that you wrote. Great insight.

I am studying for GIA distance course.. They say ( I know take with a grain of salt, but I need to pass the final) a thick girdle can create unnatractive large fuzzy gray reflections in the stone. If it''s too thick it can make the diamond stone look darker. So is that correct as you have seen or not the case??

Sorry for the threadjack but it''s a good question no???

 

[Richard Sherwood]

Hiya Kaleigh. From my experience, it is usually other factors than the girdle causing those "gray" areas.

I'm speaking of stones with thick girdles. When you get into extremely thick, there's usually a multitude of problems going on.

A well proportioned stone with a thick girdle though can look great.

I'm so thrilled you're going after your GG.

 

[Kaleigh]

Thanks Richard!!!

 

[diamanda]

Thanks everyone for all the great links and info! I was wondering about the girdle thickness because I''ve been using that as an elimination tool... any listing that has a thick+ girdle, I''ve crossed off. I should give those rocks a second look....
and Kaleigh, good luck on your final!