Paging Storm, Stone-cold, Lorelei and other diamond experts...

[Laila619]

I have a quick question for y''all...

Would this be a bad combo? A diamond I am looking at has 80 % lower girdle facets (which I like for the thinner arrows) BUT it has only 49 % stars. Is that combination bad? From what I''ve been reading the stars should be at 50-55 %, or even higher. Thanks in advance!

Oh, no chance to get an idealscope either, as it is from Blue Nile.

This stone meets all my other criteria though!

1.8 carat H SI1
AGS ideal cut
Crown angle: 35.2
Pavilion angle: 40.6
Table: 56.6 %
Total depth: 61.8 %
7.78 x 7.81 x 4.82

 

[strmrdr]

stars are fine

That is a combo however that is often best looked at by an expert before purchase.
That it got the AGS0 is a good sign however if it was gia rounded numbers I would be more concerned.

 

[Lorelei]

Date: 9/7/2009 11:35:07 PM
Author: strmrdr
stars are fine

That is a combo however that is often best looked at by an expert before purchase.
That it got the AGS0 is a good sign however if it was gia rounded numbers I would be more concerned.

Ditto. By the way I am not an expert Laila, just a consumer but thank you for the compliment! Strm is in another category altogether and is the most knowledgeable diamond consumer in the world who also happens to be on a par with the experts in my opinion in many ways!!!

 

[Laila619]

Thank you very much storm and Lorelei!

I guess what I really wonder is how important is the star %? Am I correct in that 49 % is unusually low?

I've read a lot about the stars and lower girdle facets and I think I understand lgf (the smaller the lgf = the fatter the arrows) but I don't understand the stars at all or how they affect the beauty of a diamond.

 

[Lorelei]

Date: 9/8/2009 3:23:29 AM
Author: Laila619
Thank you very much storm and Lorelei!

I guess what I really wonder is how important is the star %? Am I correct in that 49 % is unusually low?

I've read a lot about the stars and lower girdle facets and I think I understand lgf (the smaller the lgf = the fatter the arrows) but I don't understand the stars at all or how they affect the beauty of a diamond.

Most welcome Laila!

This is a good tutorial which explains more about stars

http://www.goodoldgold.com/Articles/MinorFacets/

I think this paragraph explains stars well, quoted from the above tutorial from Jonathan Weingarten, if you refer to that in the tutorial and see the examples it will become clear.

"The star facets are the windows to the hot spots (blacks observed in LightScope analysis) between the arrow heads which are directly influenced by the lower girdle facet length. When diamonds have proper lower girdle facet length, opening these windows increases the *sparks* that fly out from between the fiery arrows, thus increasing both fire and scintillation as observed in direct light conditions. Closing these windows decreases that optical effect. GIA's most recent research shows exactly what I've been discovering concerning this phenomena. Here are examples of diamonds with varying star/upper girdle ratios."

 

[Laila619]

Thank you for the tutorial! Based on that, I would say no to the 49 % stars.

 

[strmrdr]

The stars are not that critical, 49% stars isn''t a valid reason to reject any diamond that has a relatively normal crown pavilion angle combination.


With some lower crown angle combinations longer stars can help. (actually the steeper upper girdles help)
With some overly steep crown angles shorter stars can help (actually the shallower upper girdles help)
With a just slightly steep crown of 35.2 it is not an issue.

 

[Lorelei]

Date: 9/8/2009 3:58:53 AM
Author: Laila619
Thank you for the tutorial! Based on that, I would say no to the 49 % stars.

No no no, honestly its fine! The tutorial is a guide only, there is every chance the diamond in question is a great looking rock! It has great proportions and that is what matters, stars should not be an issue in this case, they aren't the be all and end all by any means.

 

[Stone-cold11]

ya, no reason to reject this stone.

 

[Paul-Antwerp]

Laila,

Storm, Lorelei and Stone are right, the stars being 49% is no reason to reject the stone.

In fact, you are concentrating on a minor detail. I suppose that you have first checked the available average proportions in the HCA. As such, you know that you should examine the stone further.

The fact that the stone obtained the AGS-0-grade is a second plus, but after that, it depends upon your comfort-level both in what you want to obtain in your diamond as in how comfortable you are with the vendor assisting you.

Like Storm mentioned, this particular combination of average proportions is one to look at with more detail. That detail is not the difference between stars being measured at 49% compared to 50%, it is a check how tight the diamond is cut within the average proportions. In other words, you are concentrating on the whipped cream, while you should be looking at the cake.

Live long,

 

[Laila619]

Thank you everyone! You all really know your stuff.