HCA =0.6 for heart&arrow diamond

[whiteolive]

is this score acceptable if the diamond is a heart and arrow diamond? most diamonds are above score of hca>1

 

[Rhino]

A .6 throws up a red flag here. There is a chance it may be just fine but I have seen scores under 1.0 also suffer from too much obstruction. Ie. head/body shadow.

 

[Paul-Antwerp]

I beg to disagree, Jonathan, describing it as a red flag is a gross exaggeration and incorrect.

As such, a score of 0.6 tells you nothing. If it was achieved in a very tightly cut stone, with the cutter truly controlling his equipment, it has all the potential to be a fire-cracker. If the score is a result of averages hiding the true angles and the facet-placement not being fully under control, it might perform less well.

To summarize: as such, the score tells you nothing, and further investigation is necessary.

Live long,

 

[diamondseeker2006]

Gee, I think that was Jonathan's entire point, it may be fine and it may not...so you have to be able to access further analysis of the stone.

 

[whiteolive]

i think i'll look for a different stone to be on the safe side.

 

[Rhino]

Gee, I think that was Jonathan's entire point, it may be fine and it may not...so you have to be able to access further analysis of the stone.

LOL ... it was.

 

[Paul-Antwerp]

i think i'll look for a different stone to be on the safe side.

And this is exactly the reaction I feared. There is essentially nothing wrong with a HCA-score of 0.6, just like there is essentially nothing great about a score of 1.1. Both pass a rejection-system, after which the quest for more info should continue.

If you simply walk away, you are falling prey to generalisations.

Live long,

 

[Gypsy]

You need to understand the tool you are using. The HCA is a pass/fail rejection tool. No score is better than another. It simply tells you which stones are worth pursing further with an ideal scope and which are not. You are frankly reading too much into the score.

An idealscope, in contrast, is a selection tool. Get an idealscope or use a vendor that can get you one of the stone you are considering. Don't make false assumptions and reject a perfectly good stone because you don't understand the data the HCA is giving you or the comments of the people trying to help you.

Listen to Paul, I find his posts generally very clear and concise and responsible. Jon's "red flag" language was unnecessarily inflammatory and his comment a bit too "short hand" for a newbie, but he was trying to help you. The the point everyone is trying to make is, as Paul explained, -- the HCA tool is limited in it's application and the ONLY thing the score tells you is that this stone worth getting an idealscope to investigate it's potential further. The only way to determine if the stone has any issue or not is to get an ideal scope. Stones that score under 2 are usually good choices but some aren't. Which is why it is a rejection tool not a selection tool. No one was advocating you reject the stone out of hand based on a limited application tool.

 

[Rhino]

i think i'll look for a different stone to be on the safe side.

And this is exactly the reaction I feared. There is essentially nothing wrong with a HCA-score of 0.6, just like there is essentially nothing great about a score of 1.1. Both pass a rejection-system, after which the quest for more info should continue.

If you simply walk away, you are falling prey to generalisations.

Live long,

We're in agreement on that bossman. I'd never make a sweeping generalization. It's just been my observation that the more you go closer to 0.0 on the HCA (or under 1.0) the greater the chances are for obstruction. But to confirm your statement above, yes I've seen HCA scores between 1.0 & 2.0 that had AGS 3 light performance.

Bottom line ... there is no crystal ball to gemology. Nothing replaces a physical inspection and even beyond cut there are so many variables that impact the value.

{edited to add} On top of an IdealScope image, equally if not more important would be an ASET exam as well.

Live long man.

 

[Karl_K]

I am not telling people what to post but the right first reaction is:
Please post all the numbers and any images you have so we can help you better.

There are a lot of combos that get a .6 some great some with obstruction issues.
As Paul said earlier the specifics can make a huge difference.

 

[Paul-Antwerp]

I would even add that, aside from the various combos, even within the same combination of average angles, one cutter will produce an absolute masterpiece, while another cutter might have produced a dud.

Live long,