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Ideal Crown and Pavillion Angles...

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llcoooooljay

Rough_Rock
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Dec 10, 2008
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Are there specific numbers that newbies should be looking for in crown and pavillion angles? i have a diamond that has a crown angle of 33.5 (is that too steep?) and a pavillion angle of 40.8. are those within a good range? please let me know. thanks
 

tmelsh

Rough_Rock
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Jan 27, 2009
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Use the cut adviser:

https://www.pricescope.com/cutadviser.asp

A score of 2 or less is ideal
 

Lorelei

Super_Ideal_Rock
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Date: 2/2/2009 4:14:17 AM
Author:llcoooooljay
Are there specific numbers that newbies should be looking for in crown and pavillion angles? i have a diamond that has a crown angle of 33.5 (is that too steep?) and a pavillion angle of 40.8. are those within a good range? please let me know. thanks




Your angles are within good range there so no worries. Here are some numbers some of us use to find a well cut round diamond.

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!





Also here are some good angle combos which might help from one of the experts John Pollard.





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).

I just wanted to add when using the HCA, scores below 2 are considered a ' pass pending further evaluation' and this is done with idealscopes etc to make sure that particular diamond is suitable for the intended purpose.




 

Ellen

Super_Ideal_Rock
Joined
Jan 13, 2006
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24,433
Date: 2/2/2009 4:23:40 AM
Author: Lorelei

I just wanted to add when using the HCA, scores below 2 are considered a ' pass pending further evaluation' and this is done with idealscopes etc to make sure that particular diamond is suitable for the intended purpose.
Ditto. Also, a Sarin or Helium report can be used to assess if IS pic is not available.

And, the placement of the x is important too. You can get a score less than 2, but have it out in no mans land = not particularly a great stone.
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