Cut Rating or HCA Score?

[supalong52]

I was browsing diamonds on jamesallen.com and I came across a stone that was rated GIA very good. I put the dimensions into the HCA calculator and it returned a 0.6, which I understand is very good.

I was wondering if, when choosing a diamond, I should narrow it down to an AGS0 first, then find something with a good HCA score, or if a good HCA score is good enough regardless of cut rating. Unfortunately, I lost the link so I can''t post detailed stats. It was probably G, VS2, 1.2ish.

 

[stone-cold11]

Need to see the actual dimensions, but I would go with HCA than with cut ratings of vendors or GIA. The only cut ratings I trust are AGS DQD cut ratings.

 

[Garry H (Cut Nut)]

after you run HCA a warning comes up under the box and it links here
http://diamonds.pricescope.com/ideal.asp

Read this and you will understand a lot more

 

[Lorelei]

Date: 12/11/2008 2:29:23 AM
Author:supalong52
I was browsing diamonds on jamesallen.com and I came across a stone that was rated GIA very good. I put the dimensions into the HCA calculator and it returned a 0.6, which I understand is very good.

I was wondering if, when choosing a diamond, I should narrow it down to an AGS0 first, then find something with a good HCA score, or if a good HCA score is good enough regardless of cut rating. Unfortunately, I lost the link so I can''t post detailed stats. It was probably G, VS2, 1.2ish.

An Idealscope image would be very useful in this case. Depending on what you are looking for, use the HCA to eliminate the lesser performers leaving you with the ones which score 2 or below. Then from the ones you like best out of those, request Idealscope images to narrow the field.

 

[neatfreak]

Date: 12/11/2008 4:16:55 AM
Author: Lorelei

Date: 12/11/2008 2:29:23 AM

Author:supalong52

I was browsing diamonds on jamesallen.com and I came across a stone that was rated GIA very good. I put the dimensions into the HCA calculator and it returned a 0.6, which I understand is very good.


I was wondering if, when choosing a diamond, I should narrow it down to an AGS0 first, then find something with a good HCA score, or if a good HCA score is good enough regardless of cut rating. Unfortunately, I lost the link so I can''t post detailed stats. It was probably G, VS2, 1.2ish.

An Idealscope image would be very useful in this case. Depending on what you are looking for, use the HCA to eliminate the lesser performers leaving you with the ones which score 2 or below. Then from the ones you like best out of those, request Idealscope images to narrow the field.

Well said...a low score doesn''t **guarantee** a good performer. It just means it should be considered so keep that in mind.

 

[Paul-Antwerp]

Very well said, neatfreak.

To explain a bit more, the HCA uses 4 averages of measurements, in order to assess a round. Using averages is never the same as assessing the real stone, and a lot of extra information might be hidden in the averages.

As a comparison, one can look at the GIA cut-grade-system. It is in some ways more refined because it works with more data, albeit all are also averages. It thus has the same limitations as the HCA.

And in a way, the HCA looks a bit more sophisticated, since it gives a number between 0.1 and 9.9, while GIA only has 5 cut-categories. Considering the limitations of using averages, one should however not get over-involved in the exact number produced by the HCA. It is a possible best score of the stone, if all details have been cut extremely symmetrically. Since nobody knows, one needs to look more into detail if the score is good enough, for instance by looking at the ideal-scope or the ASET.

Live long,