HCA Question

[Lockout888]

Can a RB with a GIA cut quality of "Very Good" do well on the HCA?

 

[stone-cold11]

yes but depends on why GIA grades it as VG, sometimes it is not worth it even if HCA scores well.

 

[antelope1]

Maybe, it depends. From what I found at GIA (http://www.gia.edu/diamondcut/06_estimating_a_cut_grade.html)

HCA uses the average angles, which are also components to the GIA cut grade. So I think you can have VG overall cut grades from GIA that score well on HCA.

The finish (polish and symmetry) matter for the GIA cut grade. (The highest score you can get with "good" finish is VG.) So you could have a diamond with good average angles, but only good symmetry or polish (or however finish is calculated). This would yield a VG overall cut grade from HCA, but get a good HCA.

(Remember, HCA is a rejection tool, not a selection tool, so you would still have to look at images of the diamond before purchase).

HTH.

 

[Lockout888]

I found a diamond with a GIA VG cut grade that has EX polish and VG symmetry. I think it got a VG rating because the girdle is slightly thick to thick. It got a 2.3 on the HCA.

 

[stone-cold11]

Thick in the girdle usually means the stone will have a slightly smaller diameter with a stone of a similar proportion but medium girdle variation.

 

[yssie]

ditto.

My old GIA VG was a beautiful stone, AGS0 by proportion but the high c/low p combo was outside GIA EX proportions. A 2.3 doesn't mean much - for the modern RB report gia averages and rounds, and the lower girdle angle is not taken into consideration, and HCA only requires a few inputs, and neither considers what make YOU prefer - so a "2.3 stone" could be very nice - the bigger issue is how much of the girdle is "visibly thick" - and how big is the stone?