Relationship between AGS0 Ideal Cuts and the HCA Score

[OCDStoneHunting]

Is there any relationship between AGS0 Ideal cut stones and the HCA score. I have read the AGS0 ideal cut is more strict than a GIA Excellent cut, and generally the proportions of the stone are more strictly controlled to make it "ideal". Would this not mean that an AGS0 ideal cut stone would have an HCA score below 2, 90% of the time?

Also, when viewing stones in person (and not buying online), how much does the HCA score weigh into the decision making?

Thanks
Isaac

 

[neatfreak]

HCA score weighs heavily for me when you can't view in person. In person, your eyes can trump the HCA and occasionally your eyes might be drawn to a stone with a slightly higher HCA score.

And yes, almost always an AGS0 should receive a score less than 2 on the HCA. I say almost because there **might** be exceptions...but I can't recall seeing one.

 

[Lorelei]

Date: 12/8/2008 10:00:47 AM
Author:OCDStoneHunting

Is there any relationship between AGS0 Ideal cut stones and the HCA score. I have read the AGS0 ideal cut is more strict than a GIA Excellent cut, and generally the proportions of the stone are more strictly controlled to make it 'ideal'. Would this not mean that an AGS0 ideal cut stone would have an HCA score below 2, 90% of the time?

Also, when viewing stones in person (and not buying online), how much does the HCA score weigh into the decision making?

Thanks
Isaac

If you are considering an AGS0 diamond and have all the info available that you need such as Idealscope etc, then the HCA's usage is limited, it isn't used to select stones but to eliminate them. With any diamond, tools such as Idealscope images which actually represent a particular diamond are considered to be more useful than HCA which cannot physically see the stone. Some view AGS0 cut grade as being a pretty safe bet cutwise.

The HCA comes into its own concerning diamonds which don't have much info available especially with non in house diamonds, if you have the depth, table and angles, then you use the HCA to run these numbers through to see which diamonds are worth further evaluation such as Idealscope etc. Stones which score 2 or below are considered worthy of further evaluation in most cases.

As to seeing diamonds in person the HCA can be very useful in order to run the numbers through for reassurance, however your own eyes are the ultimate deciding factor, make sure to compare as many diamonds as you can of known cut quality, so you have a good idea of your own particular preferences, and see if you can look at your chosen diamond in more normal lighting ( jewellery store lights can be deceiving) to make sure you like how it looks in more real life conditions.

 

[Regular Guy]

Isaac,

As my friends have said in other ways, if you have a diamond in hand, or that you''re referencing in some way, that''s received a zero for light performance from AGS...whether 90% overlap or not (probably the case)...you can I think disregard running the HCA at that point. The zero score is both based on a) a more tightly discerned measure of the diamond than HCA should anticipate, and b) as you''ve reviewed in comparison to GIA, a narrower band of constraints than HCA otherwise allows.

But..for virtually all other grading reports...the HCA should be useful to constrain your initial sort.

 

[OCDStoneHunting]

Great everyone. Much thanks for of all your input. Greatly appreciated.