Decisions ...which stone?

[chloball]

Have been trying to pick the best. Have found 2 stones with very little going on inside. Both are really clean...only wisps and some feathers.GIA facetware rates them both the same. Very different when I plugged in the numbers here (H is a buy and I should only buy the G if price is right.) Is the G too deep? Should I deffinitely nix the G? HELP...this is nerve racking! Want to do the right thing!

Round Brilliant

Measurements: 7.52 - 7.57 x 4.74 mm

Carat Weight: 1.70

Color Grade: G

Clarity Grade: SI1

Cut Grade: Very Good

Proportions:

Depth: 62.8 %

Table: 59 %

Crown Angle: 36.5°

Crown Height: 15.5 %

Pavilion Angle: 40.8°

Pavilion Depth: 43 %

Star length: 50 %

Lower Half: 80 %

Girdle: Slightly Thick, Faceted

Culet: None

Finish:

Polish: Excellent

Symmetry: Excellent

Fluorescence: Faint

Round Brilliant

Measurements: 7.69 - 7.75 x 4.64 mm

Carat Weight: 1.71

Color Grade: H

Clarity Grade: SI1

Cut Grade: Very Good

Proportions:

Depth: 60.1 %

Table: 57 %

Crown Angle: 31.5°

Crown Height: 13 %

Pavilion Angle: 40.8°

Pavilion Depth: 43 %

Star length: 50 %

Lower Half: 75 %

Girdle: Slightly Thick to Thick, Faceted

Culet: None

Finish:

Polish: Excellent

Symmetry: Very Good

Fluorescence: None

Comments: Twinning wisps are not shown. Surface graining is not shown.

 

[Ellen]

Hi chloball,

If it were me, I'd pass on both. You can do better.

Yes, the first is a bit deep, among other things. The table is a tad larger than we like to see. The crown angle is much steeper than it should be to work with that particular pavilion angle also. (and really steeper than I would ever consider)


The second one looked good, until we got to the crown angle. That's definitely more shallow than you want to go.


Here are some tips to help in your search.

Depth 60-62.2

Table 54-58

And because GIA rounds there numbers, here's a cheat sheet for crown and pavilion angles. These need to work in harmony, they determine so much of how well the diamond performs.


With that said, here's a "Cliff's Notes" for staying near Tolkowsky/ideal angles with GIA reports (their numbers are rounded): A crown angle of 34.0, 34.5 or 35.0 is usually safe with a 40.8 pavilion angle. If pavilion angle = 40.6 lean toward a 34.5-35.0 crown. If pavilion angle = 41 lean toward a 34.0-34.5 crown.

GIA "EX" in cut is great at its heart, but it ranges a bit wider than some people prefer, particularly in deep combinations (pavilion > 41 with crown > 35).

HTH!

 

[Lorelei]

Date: 9/12/2008 10:05:00 AM
Author: Ellen
Hi chloball,

If it were me, I''d pass on both. You can do better.

Yes, the first is a bit deep, among other things. The table is a tad larger than we like to see. The crown angle is much steeper than it should be to work with that particular pavilion angle also. (and really steeper than I would ever consider)


The second one looked good, until we got to the crown angle. That''s definitely more shallow than you want to go.


Here are some tips to help in your search.

Depth 60-62.2

Table 54-58

And because GIA rounds there numbers, here''s a cheat sheet for crown and pavilion angles. These need to work in harmony, they determine so much of how well the diamond performs.


With that said, here''s a ''Cliff''s Notes'' for staying near Tolkowsky/ideal angles with GIA reports (their numbers are rounded): A crown angle of 34.0, 34.5 or 35.0 is usually safe with a 40.8 pavilion angle. If pavilion angle = 40.6 lean toward a 34.5-35.0 crown. If pavilion angle = 41 lean toward a 34.0-34.5 crown.

GIA ''EX'' in cut is great at its heart, but it ranges a bit wider than some people prefer, particularly in deep combinations (pavilion > 41 with crown > 35).

HTH!

Ditto.

 

[stone-cold11]

going by the numbers, on HCA the second stone actually scores quite well, 1.1 in the BIC range. A brilliant cut, different from the traditional TIC cut. Only light return is in the very good range the rest all scored excellent.

Did you notice the difference in performance when u are comparing them visually?

 

[chloball]

Thank you all....food for thought. Am still shopping...will need to decide by Monday!