H&A vs Ideal--using the HCA

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Oct 30, 2002
I was looking at 2 diamonds this afternoon, one was 'A Cut Above' H&A and one was an AGS 000 Ideal. When I ran their pavilion, culet, depth, table, and crown information through the HCA--I got what I perceived to be interesting results.

The H&A scored a 2.0 on the HCA. The AGS 000 Ideal scored a 0.6. This surprised me as I thought the H&A 'A Cut Above' were supposed to be better quality than Ideal (though better is relative I guess). Why would there be such a large difference between the two diamonds. Is AGS 000 Ideal as a rule better indeed than an H&A cut?

Also to throw another piece of info into the mix, I ran a Blue Nile Signature Ideal diamond through the HCA as well, and it got a 2.4. I thought BN SI's were supposed to be the cream of the crop for Ideal--they are all AGS 000. So this brings up the other question, HCA scoring between AGS 000 Ideals, should there be such a spread? From a 0.6 to a 2.4 and they both score AGS 000 and 'Signature Ideal'?

If anyone has info that can help, I appreciate it, as now I am a little confused.



Oct 7, 2002
My two cents on this as I dealt with this issue early in my search:

Most of the people on this board (and the excellent creator(s) of these internet sites) will tell you to live and die by the HCA. Fine.

Most of the people in the industry have no idea what the HCA is, or if they do, think it's bunk. Fine.

Bottom line: there is little agreement in the industry about what is an "ideal" cut. And remember you want both most beautiful and a good value as perceived by the industry, IMO.

My advice (having done zero real-life comparisons between the types of grading "ideal cut") -- Pick a diamond that scores very high on all the cut scales: AGS and HCA. You won't pay any more for it. And my experience is that 75% or so of AGS000 stones score very high on the HCA anyway. That way you'll never have to worry. If you put an AGS000 into the HCA and get a poor score, pick another stone. I went through my search very patiently and discovered that there is always another stone out there. Trust me. Don't obsess over any one stone you haven't even seen in real life yet.
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