What number is good vs. bad on HCA?

[tenyearanniversary]

I got a 2.2 on the HCA on a 4.7 CT RB. But the cert says Ideal Cut. But apparently this stone is a perfect hearts and arrows?

On the other hand, a 3.66 CT RB I'm looking at scores a 1.1 on HCA, but vendor says this one is a pretty good H&A, but not perfect H&A.

Comparing these two, how can a stone with a worse HCA score have a better H&A?

Most importantly, what number on HCA do I start rejecting stones?? Anything above a 2 or 3?

Thank you very much!

p.s.: Went to try on a ton of sick rings today. I love cushions on my computer screen, but love RB's in person, as it turns out.

 

[MissGotRocks]

Typically reject anything over a 2 on the HCA. It's a rejection tool - not a selection tool. Anything from a 1.1 to a 2.0. Anything within that range is acceptable though a 1.4 is no better than a 1.9 and a .9 is not better than a 1.9.

What kind of cert did the ideal cut stone have? What were the specs on it?

 

[slg47]

a 2.2 might be fine...the HCA is only a 'chalk outline' using 4 numbers. can you get an idealscope image of the stone? that would tell more.

or post the numbers in RockyTalky if you want more input.

 

[tyty333]

Whether a stone is H&A does not signify that the angles are the best for light return. H&A signifies percision in the cuts/symmetry
but that can be done on a stone with really good crown/pavilion angles or on a stone with bad crown/pavilion angles.

From the knowledge section...

"Diamonds with H&A patterns are frequently among those with top performance. However there is no proof yet that the absence of H&A optical symmetry (or any other type of pattern) means that a diamond will have lesser performance, as it’s the overall geometry of a diamond that determines its light performance. It is possible to produce H&A diamonds with inferior performance"

https://www.pricescope.com/wiki/diamonds/hearts-and-arrows-diamonds