Question on Pavillion Angle

[me1234]

The diamond I am looking at has a pavillion angle of 41.4. It''s about 2 ct. Will there be lots of light leakage on this? Mara, what dimensions should I look for with a 2 ct round, especially if I want lots of fire?

 

[pricescope]

Me1234,

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The diamond I am looking at has a pavillion angle of 41.4. It's about 2 ct. Will there be lots of light leakage on this?
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Most probably, unless it has rather shallow crown angle (< 32.5°) to compensate deep pavilion

 

[me1234]

Why will there be leakage? With this size stone, should there a pavillion range range I should stay in?

 

[pricescope]

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Why will there be leakage?
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At certain combinations of crown and pavilion angles there are regions in the diamond where light leaves through pavilion and doesn't returns back to observer' eyes. In order to avoid leakage in a diamond with 41.4° pavilion angle, the crown should be less than 32.5°.

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With this size stone, should there a pavillion range range I should stay in?
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It doesn't depend on the carat size of the stone. You also should n0t consider pavilion angle alone but in combination with crown angle. Table size over 60% will also effect on the diamond optical performance.

This diagram shows HCA scores for table = 56%. As you can see, in order to get HCA about 2, your diamond should have crown angle less than 32.5°.

 

[Toska]

leonid, would you be able to supply one of those pictures for a 59.7 table diamond?

What do all of the colours represent?

 

[pricescope]

the difference won't be too dramatic. You'll just get some penalties for table over 58%

 

[AGBF]

Leonid,

I know you are dying for this information, so I will share it with you: your diagram above didn't frighten me one iota! It didn't have that terror effect that Josh's Portuguese cut diagram did. In fact, it looks *very* much like a topographical map of a pretty town in California. (I loved geology and physical grography.) Feel free to put up as many topographical maps as you like.

Yours as ever,
Deb

 

[Toska]

so leonid, care to tell us about what the colours represent on your nice topographical/geographical chart?

What does red mean, what does blue mean?

 

[pricescope]

Toska, there is a legend in the right-top corner of the plot. E.g. blue corresponds to HCA > 8.

See this page for more.