HCA vs. Brilliance Scope

[JD_MD]

Question:

If a diamond scores quite well on the HCA (1.4) with 2 excellent scores for light return and spread, but only very good for scintillation and fire, based only on that fact most members of pricescope would say that a much better diamond could be found if one looked around.

My question is - if that same diamond returned a triple very high on the brilliance scope, could the HCA results be completely discounted?

Thanks!

 

[Regular Guy]

I'd reverse that, and consider no to both, but I'm not an expert.

(edited to add)...ideally you won't have to be a riverboat gambler, and get a match on both!

 

[RockDoc]

Date: 6/14/2005 10:53:26 AM
Author:JD_MD
Question:

If a diamond scores quite well on the HCA (1.4) with 2 excellent scores for light return and spread, but only very good for scintillation and fire, based only on that fact most members of pricescope would say that a much better diamond could be found if one looked around.

My question is - if that same diamond returned a triple very high on the brilliance scope, could the HCA results be completely discounted?

Thanks!

Dear JD MD

I think you are trying to make a relevance to two different analyses that don''t report the same thing.

The proportional numbers are "helpful" and certainly better than not having them, but the result is still a prediction rather than actual measurement and scanning of the stone itself.

The HCA does vary depending on the input ( angles vs percentage) in it''s ratings. While there is some sort of program they have that takes the image of an actual proportion scan and this results in an image, but still the result is a calculation primarilly.

On the other hand the B Scope reports a rating which is based on actual light measurement. But just looking at the rating bars isn''t enough. You also need to observe and analyze the images it reports. Seoncdly, examination in the Viewer by human eye is very helpful in making a determnation and I think a necessary part of the B Scope analysis.

How much weight your considerations should have is of course your choice to decide in comparing each report.

You might ask yourself, which is more important to you? How the stone performs regardless of the numbers, or if you prefer to accept the HCA rating which is performed based on a prediction of how it will look?

What is the point of the proportions if the result isn''t really reconciling itself to the appearance that is based on a real life measurement? Also, isn''t the point of knowing the numbers always going to result in the best performing stone?

So in my opinion, I''d sort of give more weight to the B Scope, but I wouldn''t toss out the HCA result, However, the HCA''s rating system does prefer shallow cut stones, even Gary admits that.

So with that in mind, you can evaluate both in a way that you feel is more informative to your decision.

Hope this helps

Rockdoc

 

[Garry H (Cut Nut)]

Date: 6/14/2005 4:02:40 PM
Author: RockDoc

Date: 6/14/2005 10:53:26 AM
Author:JD_MD
Question:

If a diamond scores quite well on the HCA (1.4) with 2 excellent scores for light return and spread, but only very good for scintillation and fire, based only on that fact most members of pricescope would say that a much better diamond could be found if one looked around. HCA is used for rejection, and should not be used for "selection" unless you want a specific "look" in a diamond and so far very few people here have worked that out yet. You can have a more brilliant, or a more firey diamond - or a compromise - but not both together.

My question is - if that same diamond returned a triple very high on the brilliance scope, could the HCA results be completely discounted?
I do not believe anyone has found such a stone yet
Thanks!

Dear JD MD

The HCA does vary depending on the input ( angles vs percentage) in it''s ratings. While there is some sort of program they have that takes the image of an actual proportion scan and this results in an image, but still the result is a calculation primarilly. Roc you know very well to always advise users to use ANGLES because it is more accurate because of the scanner errors and not anything to do with HCA. Why did you write that? And what is in the program that "results in an image". After 5 years and a page devoted to HCA on your website, I would have thought you might have taken the time to understand it by now?

On the other hand the B Scope reports a rating which is based on actual light measurement. But just looking at the rating bars isn''t enough. You also need to observe and analyze the images it reports. Seoncdly, examination in the Viewer by human eye is very helpful in making a determnation and I think a necessary part of the B Scope analysis. or in other words, "send the stone to me"

How much weight your considerations should have is of course your choice to decide in comparing each report.

You might ask yourself, which is more important to you? How the stone performs regardless of the numbers, or if you prefer to accept the HCA rating which is performed based on a prediction of how it will look?

What is the point of the proportions if the result isn''t really reconciling itself to the appearance that is based on a real life measurement? Also, isn''t the point of knowing the numbers always going to result in the best performing stone?

So in my opinion, I''d sort of give more weight to the B Scope, but I wouldn''t toss out the HCA result, However, the HCA''s rating system does prefer shallow cut stones, even Gary admits that. sure do, and I am still waiting for someone to do a study on dirty diamonds. I would do it myself, but since I can not impress Roc with HCA, there is no point

So with that in mind, you can evaluate both in a way that you feel is more informative to your decision.

Hope this helps You have got to be kidding Roc - that was of no value to this person - no value at all.

If a diamond scroes well on the BS or on HCA or has a great ideal-scope image, then it is well worth considering. One option if you are buying online is to have the stone shipped to an appraiser like Roc who will probably make as much money on the diamond as the vendor - but it will give you peace of mind. If the stone has a
Rockdoc

 

[strmrdr]

To answer the original question both the hca and the b-scope are but one piece of the puzzle.
The information combined would make the decision not one piece.
What does the ideal-scope image look like?

 

[Garry H (Cut Nut)]

Why on a web Forum that hosts HCA, and you with 796 posts to your name, would you give this advice?
I just thought I''d inform the consumer that two different results can be observed. If JD ( Juris Doctor) and MD ( Meidcal Doctor) is what our reader is, then he would probably like to consider both results.
When you have read many times that the % option is there for people who have do not have access yet to angles. (Those who are looking usually at EGL and IGI stones)

"That isn''t what I am inferring. Lots of folks have the B Scope." Are you inferring that unless a vendor has Bscope that people should not buy from those vendors?
Actually what I intended you to understand is that you are shilling for business. The usually accepted method is to add value and let consumers decide if you are worthy.

I have no need to impress you or anyone else with HCA. I understand why AGS chose their viewer proximity. I disagree about that, but I respect their justification. They may or may not agree with me.

As for GIA, I am happy to bet with you that you will not be recommending many of the stones they give Excellent to. I will wager you a decent bottle of wine that there will be diamonds they give an "Excellent" grade to that are steep deep diamonds that would have been within the old AGS 0 that you would have advised consumers against.

 

[RockDoc]

From above posting.

"That isn''t what I am inferring. Lots of folks have the B Scope." Are you inferring that unless a vendor has Bscope that people should not buy from those vendors?


Actually what I intended you to understand is that you are shilling for business. The usually accepted method is to add value and let consumers decide if you are worthy.

It appears from the consumer''s posting he already has a B Scope report, as well as the HCA. Maybe I''m wrong, but I interpreted his questions as to what considerations he would make.

So if the consumer already has the B Scope report, how is that shilling for business?


I do however, at least for the moment, agree with you on the GIA Cut Grade. So for me, I''d be getting you a bottle of wine, which is a poor bet.

I am certainly hopeful that they might narrow things down a bit more. But we won''t know that until they announce their FINAL plans for cut grades.

Rockdoc