Crown and pavillion angles

[Lady_diamond]

I have ordered a diamond with a crown angle of 34 and a pavillion angle of 40.8

I have read that the ideal angles should be 34.5 and 40.8 respectively. I did not realise that the ideal angles would be so tight and narrow.

Is the below specification considered a shallow/shallow combination?
Would the angle of 34 affect the optical performance of the diamond?

I read that a shallow crown can cause more light return and increase brightness of a diamond but can kill fire. Is this likely to occur with this selection?

1.58ct
F colour
VVS2
Dimensions: 7.48 -7.53x4.62mm
LW ratio 1.01
Table 56%
Depth 61.6%
Medium faceted girdle (3.5%)
Pavillion angle 40.8
Crown angle 34
Faint Flurosence.
The only inclusion reported is a pinpoint and that is at 7 o clock within the periphery of the crown when looking down.
HCA score: 1 - within TIC

Your opinions would be appreciated (I am trying to learn!)

 

[Diamond_Hawk]

Those angles are within parameters for a diamond that could perform very well - certainly, as the HCA indicates - it is worth 'further investigation"

If you can get a scientific image ( IdealScope or ASET) of the diamond you will get some great feedback here I am sure. It looks very promising.

 

[MelisendeDiamonds]

I have ordered a diamond with a crown angle of 34 and a pavillion angle of 40.8

I have read that the ideal angles should be 34.5 and 40.8 respectively.

Nonsense.


I did not realise that the ideal angles would be so tight and narrow.

They aren't.

Is the below specification considered a shallow/shallow combination?

Not at all its at the pinnacle of cut proportions for balanced performance.

Would the angle of 34 affect the optical performance of the diamond?

the 34/40.8 combo with perfect symmetry is one of the most balanced and favorable combinations possible.
You would need images to check the optical symmetry and other aspects like minor facets.

I read that a shallow crown can cause more light return and increase brightness of a diamond but can kill fire. Is this likely to occur with this selection?

No this is as balanced a combo as possible and likely would not be noticeably different from 34.5/40.8 the rounding of 8 angles is more important than the 0.5 difference.


1.58ct
F colour
VVS2
Dimensions: 7.48 -7.53x4.62mm
LW ratio 1.01
Table 56%
Depth 61.6%
Medium faceted girdle (3.5%)
Pavillion angle 40.8
Crown angle 34
Faint Flurosence.
The only inclusion reported is a pinpoint and that is at 7 o clock within the periphery of the crown when looking down.
HCA score: 1 - within TIC

Your opinions would be appreciated (I am trying to learn!)

Images would be helpful, this combo is highly sought after and amongst the safest when you can't view the diamond prior to purchase but without images the fine nuances of the cut (like optical symmetry) cannot be ascertained.

 

[Gypsy]

It's a great combo.

These are a stat ranges we give out as a conservative cheatsheet. Many diamonds outside of these parameters will perform well as well, but this is the conservative listing. As you can see you fall smack dab in this range.

"depth - 60 - 62% - although my personal preference is to allow up to 62.4%
table - 54- 57%
crown angle - 34- 35 degrees
pavilion angle - 40.6- 41 degrees
girdle - avoid extremes, look for thin to slightly thick, thin to medium etc
polish and symmetry - very good and above

note - with crown and pavilion angles at the shallower ends ( CA 34- PA 40.6) and steeper ( CA 35- PA 41) check to make sure these angles complement in that particular diamond - eyeballs, Idealscope, trusted vendor input - check as appropriate! "

-From Lorelei

 

[Gypsy]

Additonally:

from John Pollard:

"As the above implies [cheat sheet], configurations depend on each other. A little give here can still work with a little take there.
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)."