HCA

[spartan183]

What is HCA and how important is it?

 

[jstarfireb]

HCA stands for Holloway Cut Adviser and can be found here:
https://www.pricescope.com/cutadviser.asp

It''s a tool to evaluate the cut of a round brilliant diamond based on proportions. You put in a few numbers and it spits out an evaluation of the diamond''s brightness, fire, scintillation, and spread, and it gives a composite number score. It''s really a weed-out tool in that it tells you what NOT to consider (higher numbers are bad). Most people here prefer an HCA in the 1-2 range, but 0-1 is often fine too. But say you found 2 diamonds...one is 1.3 and one is 1.7 on the HCA. You can''t really say the 1.7 is any worse than the 1.3 since they''re both in the ideal range. That''s what I mean by it being a weed-out tool rather than a rule-in tool.

I don''t know the science behind it or anything...I''m just repeating what I''ve heard on this forum, so if anyone finds errors in what I''ve said, please correct me!

 

[Garry H (Cut Nut)]

if you found a stone that was a little high in pavilion and or crown angles with HCA 2.5 that was known to be very symmetrical (and slightly painted helps too) then it should still be considered.
After you have narrowed the field then look at ideal-scope / ASET images and other tools