Why did this diamond get this AGA cut class grade?

[smoothsailing]

I'm still becoming familiar with all these things (like AGA cut class), so I'm not entirely knowledgable. I want to buy a Blue Nile signature ideal cut round diamond.

The diamond I'm considering got an HCA score of 1.4. Light return, fire, and scintillation were all graded excellent and spread was graded very good.

On the AGA cut class grader, the diamond got a total grade of 4A. Doesn't this mean that it is a below average cut? If it's getting this overall grade, should I NOT buy it? Here are the details from the AGA grader:

Length:6.83
Width:6.86
Depth:4.22
Total Depth:61.65%
Table percent:57
Crown height:61.6
Girdle (from):Medium
Girdle (to):Medium
Polish:Excellent / Very Good
Symmetry:Excellent / Very Good
Crown angle:34.5
Pavilion depth:40.8

Tab Percent: 1A
Crown Angle: 1A
Crown Height: 4B
Pavilion Depth: 3B
Girdle: 1A
Depth: 1A
Polish: 1A
Symmetry: 1A
TotalGrade: 4A

It is a signature ideal cut from Blue Nile, 1.21 carat, D, VS1.

 

[jstarfireb]

I think the crown height sounds incorrect, and that's what's getting you the lower AGA grade. Crown height should be more like 15%...I think you just copied the depth accidentally? Also, I'm not sure if your "pavilion depth" is actually referring to the depth or the angle (40.8 sounds more like angle than depth).

 

[smoothsailing]

I think the crown height sounds incorrect, and that's what's getting you the lower AGA grade. Crown height should be more like 15%...I think you just copied the depth accidentally? Also, I'm not sure if your "pavilion depth" is actually referring to the depth or the angle (40.8 sounds more like angle than depth).

Thank you! I did enter those two values incorrectly. I fixed it and ended up with a total grade of 1A. Makes me feel a lot better about purchasing this diamond!

 

[jstarfireb]

No problem. Glad it worked out!

 

[Amys Bling]

Glad you figured out the mistake.

 

[oldminer]

You had me worried for a second and then I saw the error, too. Glad your concerns were short-lived.