using the HCA

[lay3r3]

I would imagine this is an obvious question for a first time buyer

I''m looking at diamonds and comparing the online list that this site makes available (which is great by the way) and rarely do I see all the necessary information to use the HCA. I have several stones I''ve considered both online and through dealers but only get the Depth % Table % and dimensions. Is this normal? Should I be calculating the crown angles and such off this information? For example, I looked at a .76 with 5.99x5.92x3.92 dimensions and 58.6% depth and 58% table. Any suggestions? Should I ask for this information? Thanks in advance for helping out a newbie!!!

David

 

[pricescope]

Hi Lay3r3, welcome to the forum

GIA does not include crown and pavilion angles in their reports. If you want to use HCA, you have to ask your vendor to provide you with Sarin or Ogi measurements for your diamonds. Make sure to use angles not depth%.

 

[RockDoc]

Proportins do have SOME bearing on the light performance of a stone, but it is not 100%.

Most consumers really are concerned with the light performance of the diamond.

This is where researching the balance and intensity of the light return, internal crystal structure, and BOTH external and internal symmetry is crucial.

The other interesting part is that so many experts advise consumers to rely on only the partial numbers... Even AGS's cut grade system only reports on 17 of the 58 facets in a round brilliant.

It is the other 40 facets, that need to be known to completely understand how well these facets are aligned with each other. This separates "the men from the boys" and the GREAT performing stones from the excuses for greatness.

Make your purchasing decision, by being well informed of all the information you should know.

Rockdoc