HCA: Good score but not inside AGS''s Idea?

[dww777]

Hi Everyone,

I''m confused.. I found a diamond that has a very good HCA score: 0.6. However, on the HCA chart, this diamond falls outside the "White outline," which is supposed to represent AGS''s Ideal standard. So the main concern is this: Should I look for a diamond with a combination of good HCA score and having it fall within both AGS and GIA ideals, OR should I make my selection strictly based on the HCA score?

The specs of the diamond is as follows:
Depth%: 59.9
Table: 57
Crown Ang: 33
Pavilion Ang: 41

Thanks.

 

[JulieN]

the outline is AGS candidates, so you can be outside and get 0, and you can be inside and ! get 0.

HCA score is good, and the x falls just to the left (shallow) side of the outline, but within the GIA EX grade. If want to play safe, you might go for something that is HCA and GIA and AGS approved. If you understand the limits of each system and the reasoning why one system is different (or why one system prefers different proportions) over another system, you have a wider pool of candidates.

AGS performed their cut observations at a farther distance than Garry thinks most people look at stones. So you/she create a lot of head obstruction, you might want to stay away. Otherwise, I think it is fine.

As expounded, you cannot make selection based on HCA.

 

[Garry H (Cut Nut)]

Date: 9/5/2008 11:33:23 PM
Author: JulieN
the outline is AGS candidates, so you can be outside and get 0, and you can be inside and ! get 0.

HCA score is good, and the x falls just to the left (shallow) side of the outline, but within the GIA EX grade. If want to play safe, you might go for something that is HCA and GIA and AGS approved. If you understand the limits of each system and the reasoning why one system is different (or why one system prefers different proportions) over another system, you have a wider pool of candidates.

AGS performed their cut observations at a farther distance than Garry thinks most people look at stones. So you/she create a lot of head obstruction, you might want to stay away. Otherwise, I think it is fine.

As expounded, you cannot make selection based on HCA.

Correction - AGs used about 8 inches (20cm) - I use 14 inches 35cm.
Read all the notes that you can link to after you do a search.
An ideal-scope image will show you more buying info. HCA says it is worth enquiring further.

 

[JulieN]

whoops! you''re absolutely right...

I made the mistake because, if you consider the left, bottom corner of the HCA chart to be 0 distance, the AGS outline is on the right (farther distance.)

 

[dww777]

Thanks for the info. Although I would love to examine the diamonds in person, I''m planning to buy online... As such, all I can rely on is the numbers.. So simply based on numbers, would you suggest going for a lower HCA score is more prudent than finding a stone with a slightly higher HCA score but meets both the AGI and AGS ideal standards?

 

[Lorelei]

Date: 9/6/2008 3:06:24 AM
Author: dww777
Thanks for the info. Although I would love to examine the diamonds in person, I'm planning to buy online... As such, all I can rely on is the numbers.. So simply based on numbers, would you suggest going for a lower HCA score is more prudent than finding a stone with a slightly higher HCA score but meets both the AGI and AGS ideal standards?

The HCA doesn't work that way, a lower score isn't better than a higher one, the HCA is used for rejection - not selection. Diamonds scoring 2 or below are worth further consideration which you do with Idealscope, vendor / appraiser input and lastly your own eyes. Also in some cases diamonds scoring over 2 with top symmetry can also be worth a further look.

As Garry says, ask for an Idealscope image for the diamond, it is worth exploring further.