HCA 0.3 for RB H vs2

[fettucine]

I had a questions for experts. The HCA calculator generally recommends anything less than 2 as having good light properties. But how low is good? For example a diamond scoring 0.3 is clearly out of the AGS bracket and is bordering on the GIA excellent bracket. Is this is a good thing. Please help.

Following are the properties

Table: 55%
Depth: 60.4%
crown: 34 degrees
Pavillion: 40.6 degrees
Round Brilliant H vs2, 1 carat

thanks,
-f8

 

[aljdewey]

Date: 6/27/2006 2:45:12 PM
Author:fettucine
I had a questions for experts. The HCA calculator generally recommends anything less than 2 as having good light properties. But how low is good? For example a diamond scoring 0.3 is clearly out of the AGS bracket and is bordering on the GIA excellent bracket. Is this is a good thing. Please help.

Following are the properties

Table: 55%
Depth: 60.4%
crown: 34 degrees
Pavillion: 40.6 degrees
Round Brilliant H vs2, 1 carat

thanks,
-f8

There is no definitive cutoff, per se, but it has been noted here previously that scores of 0.6 or below *may* have lack of contrast.

I think that''s why you''re seeing this outside the AGS0 box and on the fringe of GIA ex.....shallow pavilion plus shallow crown may result in lack of contrast.

 

[Mara]

ditto what al said...a score of 0.3 with those specs would be too white brilliant of a stone for me. i prefer an HCA of more like 1 and on that kind of stone, i'd want to see a slightly higher pav angle at least.

ETA...i ran the stone through the hca and it got a 0.5...where did you get a 0.3?

 

[diamondseeker2006]

I did it twice and got .5.

 

[Lorelei]

So did I. Welcome Fettucini

 

[fettucine]

Sorry, I rechecked the gia report. The pavillion is 40.5 not 40.6 (hence HCA of 0.3)
But thanks everybody for the clarification. I thought the lower you went on the HCA the better it was, but apparently too loo is not that good either. But I don''t understand what too much white brilliance is? Does that mean a theoretical briallancescope result would be VH for the white, and lower on the other two (i.e. less fire and scintillation (eventhough HCA says excellent fire and scintillation))? Just trying to put it in my novice perspective. Should the HCA then be adjusted to show that lower scoring stones should be bought if the "price is right" or is it more of a personal preference thing. Overall I agree that I have to see the stone with my own eyes.

Thanks much,
-f8

 

[aljdewey]

Date: 6/27/2006 3:43:09 PM
Author: diamondseeker2006
I did it twice and got .5.

It''s likely that the OP is giving the score result as found through a cut quality search.

When it does that, it factors in the girdle (because it has the girdle information right there).

When you ladies are entering the data, there is no spot to alter girdle assumptions. Girdle is assumed to be medium, hence the differing score.

 

[Mara]

the way i tend to think about it is that the stone would not have as much of that dark black and gray contrast scintillation in different lights that helps both the fire and the white light actually show up to it''s best advantage.

it''s kind of hard to explain though for me.

 

[strmrdr]

It would make an awesome pendant but I wouldnt put it in a ring myself.
It will better from the longer viewing distance than in a ring.