Am I reading into this stone's HCA and PGS correctly?

[TitanCi]

I was looking at this stone locally for kicks and I plugged in the numbers to the HCA and got a 4.0.

Here are the specs:
1.36 Ct. RB, F VS1

7.12x7.14x4.39
D%: 61.6
T: 58
C: 33.5
Pav: 41.4
pav depth: 44.0%
star 50%
LH 75%
C ht 13.5%

HCA scores is good (4.0), but according the 11/07 PGS combo chart, it scores a 0 (AGS 0???)/AGS gold 2008 excellent (http://www.octonus.ru/oct/mss/gia-agspgs.phtml). How is this possible? Am I missing something? Is the HCA really saying this is a poor performer although to the naked eye, it seems very decent?? This seems to be conflicting. Can anyone share some insight into this, although it is unseen to you?


Thanks!

 

[TitanCi]

Re: Am I reading into this stone's HCA and AGSPGS correctly?

Nevermind... looks like someone in a different thread has the same concern for a stone similar to this one!

 

[TitanCi]

Ok.... Now I'm really confused.. I plugged these numbers into gem advisor and the IS images aren't bad. So why are the hca numbers bad? Is this stone worth considering too??

 

[0-0-0]

As some of us stress again and again, the HCA is really just a starting point. IMO the HCA is largely irrelevant as soon as you have images, and especially so if you can see the stone in person and compare it with other well cut candidates. You may find what I posted in another thread interesting:

IMO it's best to use the HCA to shortlist candidates and not for selection. A HCA score under 2 simply suggests that a stone is more likely to be well cut. There are well cut stones with a HCA score above 2, but it is doubly important to see images or the stone in person before committing to the purchase. Keep in mind that the HCA only considers 4 rounded and averaged measurements to give a rough estimate of a stone's cut quality, and even stones graded by the same lab with the same cut grade with identical numbers can look slightly different depending on the variances that go into the numbers.

Here's an example of 2 stones with pretty much identical numbers on the reports, both AGS 0 and both with a HCA score around 3. Neither is likely to be a bad choice based on cut, but I think it's pretty clear one displays more optical symmetry and is better cut. Yet the difference is likely lost if you only had access to the reports.

http://www.jamesallen.com/diamonds/G-SI1-Ideal-Cut-Round-Diamond-1441127.asp



http://www.jamesallen.com/diamonds/F-VS1-Ideal-Cut-Round-Diamond-1336423.asp