cut advisor ?

[flowergurl]

Could someone comment on why a diamond that has numbers outside of ideal parameters can score this well on the HCA (1.2)?
specs: D- 58.5, T- 59%, CA- 31.9, PA- 40.8
It seems shallow and the crown angle not as steep as it should be, yet it scores well on the HCA and is very sparkly.

 

[hoorray]

I''ll parapharase, Garry can correct me if I get it wrong, but the HCA is about measuring the combination of the cut parameters to determine a predicted performance for a stone. It works under the theory that an individual measurement by itself doean''t guarantee good or bad light reflection etc, it is how the angles interact with each other that determines the actual performance of the stone. (Do some searches here for more details -- there are good pictures and graphs to show some of the simulated light reflection with different angle combinations.)

Thus, your stone has a shallow crown complimented by a steeper paviion, and acording to the HCA algorthims, should perform nicely.

 

[Garry H (Cut Nut)]

Some people would say your diamond is too shallow - if you can focus at 6 inches to 10 inches from your eyes you will find the stone appears dark and lacks scintillation.
I think that is silly because few people look from so close up.

At 16 inches away from your head (less lights blocked) your stone will outperform most.

Also HCA adds a penalty for less spread and yur stone has about 5% bigger spread