Why doesn''t AGA grading use pavilion angle?

[JOE_Q]

I''ve noticed in the Pricescope tutorial that AGA uses pavilion depth % not angle. Ok what really burns me is that the pavilion depth % of the diamond I purchased measures 42.4% (class 2A) not even ideal. The more I look at my rock, the more concerned I become. Would you please take a look at the diamond and tell me your thoughts.
http://www.goodoldgold.com/1_50ct_e_vs2_h&a.htm

Thanks a lot and sorry to be a pain.
Joe.

 

[oldminer]

AGA does not use pavilion angle, but uses pavilion depth percentage because the percentage applies to diamonds of all shapes. The angle varies on fancy shapes, but the percentage depth of the pavilion is the relation of width to depth and is a constant in any shape fancy. The same happens with rounds in that pavilion percentage is a constant where the angles may vary a bit around a stone.

In rounds, the pavilion angle is directly related to the pavilion depth. It is simple trigonometry. The slight variable is culet size, but nearly every modern cut diamond today has virtually no culet facet and is just about pointed. Therefore, pavilion angle is normally in direct relationship to pavilion depth percentage. No need to give people two numbers that generally move in absolute unison with eachother.

As far as BUYING a diamond that you have some objection to, one would be tempted to ask "Why did you buy it if you do not like it?" If you like it, then what is making you annoyed, a percentage number? Don't take it so seriously. You can make excellent judgments about the quality of cutting with percentages and angles, but every diamond is a little different and every buyer hopefully buys what they want. Nothing pleases like the actual appearance of a diamond. It is more than cold numbers and charts. The final analysis of a stone is how well you like it compared to the others you might have selected.

I trust that will answer your questions and raise your spirits, too.

 

[JayTee]

hmm, well I took the numbers and plugged them into HCA (Holloway Cut Advisor) and got an excellent score. Your stone scored x-x-x-vg 0.7 TIC, which is with Ideal cut range. Sounds like this is a very good stone.

If you would like more information about the AGA Cut classes verses the HCA, check this article on AGA's site:



This might help you to distinguish between the two and figure out which one will be more helpful to you in your decision[/u]

 

[Lugus]

I agree with the above posts. I considered the stone you purchased, and I thought it looked great. Numbers aside, is there anything to be concerned about?

Though I haven't seen in in person, the only reason I didn't buy that particular stone is I wanted one a tad larger.

 

[aljdewey]

Joe:

The link you provided shows the information on crown and pavilion angles....the crown angle is 34.3; the pavilion is 40.7. If you plug that info along with total depth, table size & culet into the HCA you'll see that your stone rates a 0.7; any stone below 2.0 is fabulous. I wouldn't worry if I were you; you're getting an exceptional diamond.

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On 1/24/2003 12:26:31 PM JOE_Q wrote:

I've noticed in the Pricescope tutorial that AGA uses pavilion depth % not angle. Ok what really burns me is that the pavilion depth % of the diamond I purchased measures 42.4% (class 2A) not even ideal. The more I look at my rock, the more concerned I become. Would you please take a look at the diamond and tell me your thoughts.
http://www.goodoldgold.com/1_50ct_e_vs2_h&a.htm

Thanks a lot and sorry to be a pain.
Joe.
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[aljdewey]

Joe:

The link you provided shows the information on crown and pavilion angles....the crown angle is 34.3; the pavilion is 40.7. If you plug that info along with total depth, table size & culet into the HCA you'll see that your stone rates a 0.7; any stone below 2.0 is fabulous. I wouldn't worry if I were you; you're getting an exceptional diamond.

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On 1/24/2003 12:26:31 PM JOE_Q wrote:

I've noticed in the Pricescope tutorial that AGA uses pavilion depth % not angle. Ok what really burns me is that the pavilion depth % of the diamond I purchased measures 42.4% (class 2A) not even ideal. The more I look at my rock, the more concerned I become. Would you please take a look at the diamond and tell me your thoughts.
http://www.goodoldgold.com/1_50ct_e_vs2_h&a.htm

Thanks a lot and sorry to be a pain.
Joe.
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