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If I don''t have the HCA calculator with me, what CUT guidelines should I use?

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tlh

Ideal_Rock
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Dec 31, 2008
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I''m trying to steer my friend in the right direction for his FF''s ring purchase.

I''ve found this article helpful http://journal.pricescope.com/Articles/71/1/6060-or-ideal-cut--How-do-you-know-what-to-choose.aspx when breaking down good diamonds to take a look at...

Table 52-60%
Crown Height - 13.5-16.8% Crown Angle - 33-35.1
Pavillion Depth - 42.5 - 43.5
Total Depth 58.3 -67.99 %
Girdle - V. Thin - Med OR Thin - Sl. Thick
Polish - SYm. EX - VG

But my question is, the AGS0 with the HCA calculator has different %''s and I couldn''t find the info for the rest...
Depth 58.7-62.3%
Table 53-58%
crown angle 34 (is there a range?)
pav angle 40.5 (I couldn''t find a range..)
no culet

what general guidelines do YOU use to rule out diamonds??? Thanks so much!!!!!!!
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You can print this out and take with you, these are some numbers some of us use in order 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!

As the above implies, configurations depend on each other. A little give here can still work with a little take there.



From expert John Pollard.



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).



 
thanks that is helpful!
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Date: 5/22/2009 1:11:57 PM
Author: tlh
thanks that is helpful!
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Most welcome my dear!
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