FIC with 57 table?

[song433]

Hi Everyone,

Looking at a FIC HCA score 1.9 diamond with the following properties. I have read on other threads that table should be between 53-55 and this one has a 57 table. Is this too big? Thanks!

GIA Cert:
Table: 57%
Depth: 62.3%
Crown Angle: 36 degrees
Crown height: 16%
Pavilion angle: 40.6 degrees
Pavilion height: 43.0%
Star: 50%
LCF: 80%
Girdle: Medium - slightly thick

Thanks everyone.

Song

 

[marymm]

Well, when you run the numbers in HCA, it scores a 1.9 - Excellent within FIC Range, with Excellent for Fire, and Very Goods for Light Return, Scintillation, and Spread. So technically, no, the table is not too big for it to be an FIC... whether the table is too big for your preference or for your FIC ideal is another matter entirely. It also scores within the AGS O white outline box, so likely would be a beautiful stone if you are looking for an FIC.

 

[John P]

No worries about the table size. By the numbers this combination has very cool potential. Any chance of an ideal-scope or ASET? What carat weight or mm dimensions are you looking at here?

 

[song433]

Thanks for the responses!

I'm going to go see the diamond in person this weekend. I will ask to see if it's possible to do an ASET. This diamond is a 1.3 carat 6.95-6.98 x 4.34mm.

Also when I plugged in the crown and pavilion % instead of the angles it came back with a higher HCA score (>2.5). For GIA certs is it better to trust the angles, % or a combination?

 

[John P]

This diamond is a 1.3 carat 6.95-6.98 x 4.34mm. Also when I plugged in the crown and pavilion % instead of the angles it came back with a higher HCA score (>2.5). For GIA certs is it better to trust the angles, % or a combination?

Great question.

The greatest 'aberration-shallow' would be 40.5 / 35.8: HCA 0.9
The greatest 'aberration-deep' would be 40.7 / 36.2: HCA 2.9

Truly an interesting example with a heavy swing in "HCA potential..." But do remember the HCA is only drawing a presumed chalk-outline of a few limited angles. It's not specific.

For what it's worth, I worked with the numbers and I arrive at 1.30 carats by combining the given mm measurements and proportions with a 40.7 pavilion angle.

I will ask to see if it's possible to do an ASET.

That would be helpful for this kind of "long-distance" commentary.

 

[diamondseeker2006]

Not sure where you saw table parameters but ideal/excellent cut stone tables are usually between 54-58% (and can be larger but I stop at 58 personally).

 

[JulieN]

Numbers are fine. Go see if you like it.

 

[gregchang35]

a silly question.... what is an FIC??

 

[song433]

a silly question.... what is an FIC??

Hey Greg, see link below.
http://www.diamond-cut.com.au/23_bicfic.htm

 

[gregchang35]

thanx!
add- there is just soo much more to round brilliants than i ever knew existed!

 

[song433]

For what it's worth, I worked with the numbers and I arrive at 1.30 carats by combining the given mm measurements and proportions with a 40.7 pavilion angle.

That's interesting! May I ask how you got to that? Also did you use 36.2/35.8 or something in between for crown angle?

From the looks of it it's a slightly higher HCA score. I do like the idea of the higher crown angle combined with the other good proportions. I'll just have to go take a look .

 

[John P]

For what it's worth, I worked with the numbers and I arrive at 1.30 carats by combining the given mm measurements and proportions with a 40.7 pavilion angle.

That's interesting! May I ask how you got to that? Also did you use 36.2/35.8 or something in between for crown angle?

Sure. I used DiamCalc (cut nerd software) and entered all of the different permutations possible; accounting for GIA's rounding ranges. 1.30 was best arrived-at using the given mm measurements with 57T flat, 40.7/36.0... Now do be aware that this is just software. The calculated weight cannot account-for the influence of clarity characteristics, etc. But it's sure fun to play-with.

From the looks of it it's a slightly higher HCA score. I do like the idea of the higher crown angle combined with the other good proportions. I'll just have to go take a look .

Good deal. That's the best way to make judgments, period.