Great HCA Score but without Excellent cut grade?

[nodomo]

I was looking at a GIA diamond that had a great HCA 1.2 score. However, the cut grade was only average at "Good". GIA did not rate the cut "Excellent" or "Very Good".

I had always thought that cut determines light/fire performance and that only Excellent/Ideal cut diamonds would have the right proportions to deliver a good HCA score (<2). Am I wrong?

Here's the GIA data:

Color: I
Clarity: SI2
Cut Grade: Good
Polish: Excellent
Symmetry: Excellent
Flourescence: Faint
Depth: 59.8%
Table: 57%
Crown Angle: 32.5%
Pavilion Angle: 40.4%
Girdle: Med to Slightly Thick

 

[Karl_K]

Pavilion Angle: 40.4% with a 32.5 crown <--- good in a pendant or earring which is why it got a good hca score, not so good in a ring which is why it got the gia grade.

so:
earring - yes with more info that checks out
pendant - yes with more info that checks out
ring - no