Cut Grade Question

[FB.]

Looking at the > HCA < there''s a graph with coloured zones, with the GIA and AGS top grades on the upper right edge of an orange band.

Why doesn''t the highest grade extend further into the lower left part of the orange-coloured area?

Clicking on a link on the HCA page, it takes me to a page where it implies that stones in the AGS and GIA top grades are best suited to "young people rings", with those falling in the middle of the band are best for "older people rings" and those on the lower left of the band are best for "earrings and pendants".

I recently input details for the following stones (after a visual inspection) (both are D colour, IF clarity), which sit in the lower left part of the orange zone of the HCA:

Depth 60.8%
Table 56%
Crown height: 15%
Pavilion depth: 42%
Girdle: medium
HCA: 1.4

Depth 59.7%
Table 54%
Crown height: 15%
Pavilion depth: 42%
Girdle: medium
HCA: 1.8


Thanks,
FB

 

[Lorelei]

Date: 7/20/2009 7:56:04 AM
Author:FB.
Looking at the > HCA < there's a graph with coloured zones, with the GIA and AGS top grades on the upper right edge of an orange band.

Why doesn't the highest grade extend further into the lower left part of the orange-coloured area?

Clicking on a link on the HCA page, it takes me to a page where it implies that stones in the AGS and GIA top grades are best suited to 'young people rings', with those falling in the middle of the band are best for 'older people rings' and those on the lower left of the band are best for 'earrings and pendants'.

I recently input details for the following stones (after a visual inspection) (both are D colour, IF clarity), which sit in the lower left part of the orange zone of the HCA:

Depth 60.8%
Table 56%
Crown height: 15%
Pavilion depth: 42%
Girdle: medium
HCA: 1.4

Depth 59.7%
Table 54%
Crown height: 15%
Pavilion depth: 42%
Girdle: medium
HCA: 1.8


Thanks,
FB

It doesn't matter where it falls so much within the GIA/ AGS box, just that it hits there - that is what most aim for. With the highest grade do you mean HCA scores? All scores below 2 in most cases are considered equal pending further evaluation, a higher score isn't better than a lower.

With the ring zones, this is in the creator of the HCA's opinion and studies due to the age groups various eyesights and preferences. Shallower stones can look better in pendants and earrings due to obstruction, this is where the viewer's head/ body can block the light to shallow proportioned diamonds if worn in a ring obstructing the light in some conditions. If worn in pendants or earrings these stones aren't subject to the same viewing conditions which cause obstruction so not an issue.

 

[stone-cold11]

Date: 7/20/2009 7:56:04 AM
Author:FB.
Looking at the > HCA < there's a graph with coloured zones, with the GIA and AGS top grades on the upper right edge of an orange band.

Why doesn't the highest grade extend further into the lower left part of the orange-coloured area?


Clicking on a link on the HCA page, it takes me to a page where it implies that stones in the AGS and GIA top grades are best suited to 'young people rings', with those falling in the middle of the band are best for 'older people rings' and those on the lower left of the band are best for 'earrings and pendants'.

Angles are more accurate for the HCA.

Regarding GIA/AGS zone, several reasons that I can think of. One being the obstruction issue you have noted. Another being the target market is ring stones for young people's engagement ring, which accounts for the majority of the stones sold I would think. Also, a pavilion results in more waste during cutting from the rough.