Big stone...large table....

[roppongi]

I have been shown this stone. I have asked for the sarin numbers but my jeweler is unable to get them. Please note that I have complete trust in them as they have been my jeweler for the past 7 years. I just want to know what the concensus is on a larger table stone. How would it impact the brilliance?

Thank you for your help and feedback.

3.01 RBC
9.23 - 9.27 x 5.66
Depth 61.2
Table 62
Girdle Medium to thick, faceted
Culet None
Polish Very Good
Symmetry Very Good
Clarity Grade SI1 (totally eye clean front and back)
Color F
Fluouresence None

 

[eitan]

big table will make your stone more sparkling
if the table was small you get more fire
its 2 different things sparkling and fire
if you ask what nicer ....
i can tell you that both of them amazing
its depend in your personal taste

eitan
israel-diamonds

 

[pricescope]

Roppongi, welcome to the forum

.

However, human perception of brilliance is not the same as the light return which also depends on dynamic contrast of the diamond, which cannot be estimated based only on table and depth numbers.

In the case of this particular diamond, 62% table combined with 61.2% total depth will not give you best combination of crown and pavilion angles. I.e. diamond will have noticeable light leakage.

The diamond can still be pretty but not an ideal cut.[/u]

 

[new new]

oh, from the depth and table size, you can guess the possible number of crown and pavilion?

I saw a GIA certified diamond with 59% depth and 63% table, no crown and pavilion information, what do you think the possible effect?

 

[trichrome]

Leonid....

hmmmm...... I don't agree completely with you on this one....

a diamond with a 62% table and 61.2 TD doesnt mean necessarely that you'll get
lotsa of light leakage...

You can simply have a terrific diamond with such a table... a table this size
will make your diamond look around 10-15% bigger if not more... maybe you'll
end up with little less fire.......but I still remember the day when I was blinded by
a flash of light when examining the 63%Yable/61%TDepth diamond of my fiance....

and if you need to put your money elsewhere, a diamond like this will go up to 30-40% off Rap...
!!!!

Trichrome.

 

[Richard Sherwood]

I'm afraid Leonid's got the advantage on you, TriChrome.

With the DiamCalc, you can enter all the figures except crown and pavilion angle, and then vary these two parameters to see how they affect light performance. If you decrease the crown angle, the pavilion angle increases accordingly, and vica-versa. It's a very direct relationship, because all the other parameters (total depth, table size, girdle thickness, culet size) "box in" the possibilities.

This way it's possible to see the range of light return performance dictated by this relationship between the crown and pavilion angle. Usually a pattern of positive or negative performances will emerge throughout the range tested.

Perhap's your fiancee's stone had a good crown/pavilion angle relationship.

 

[tonysgeko]

Rich, what is the largest table % you've seen on a diamond? Did the diamond still look and perform good? Just curious.

 

[Richard Sherwood]

The largest you usually encounter on a round are in the mid 70's range. They usually don't look so hot.

I've seen plenty in the low-to-mid-to-high 60's range that looked great.

 

[Mara]

Yeah like mine!!

The crown and pav angles are crucial in these larger tabled stones. If my crown was more steep, it would NOT have looked as good. I have played around with the angles in the HCA of my stone to see where things would start to change and make the more less desirable on the specs.

The larger the table (e.g. when you start to get into high 60s and low 70s), the less sparkle from the facets ...and more of the large table. The table is a large flat area regardless and acts kind of like a reflecting mirror at times. So do you want 75% of your stone to have a large flat area? What about the facets, those which actually create/enhance sparkle? Lower 60's can be okay, but its the higher ones that can be scary. I've seen a few pictures, it looks like a big flat thing on top with some facets on the sides. It throws a big circle of light, not myriad little sparkles. Not impressive!

 

[digimond]

what do you guys think of a 64% table and 60.9% depth..since it is GIA certified, I have no idea about the angles?

Is 64% table size too big?

 

[Richard Sherwood]

Not necessarily, depending on your tastes, but those angles are critical for determining if it's a well-performing stone or not.

64% table is right at the tail-end of the AGA Cut Class "2B" for that particular characteristic. The 2B category is designated as "international fine trade cut".

You can view the AGA charts at:

http://www.gemappraisers.com/index.htm