no crown and pav angle on GIA cert

[CareBear]

I''m looking at a RB stone with 60.1% depth and 56% table GIA ex/ex. That''s all the information I have so far. Before I ask the vendor to call in the stone, what are the chances that this stone would have a crappy crown and pav angle?

 

[Garry H (Cut Nut)]

If the girdle is thin you have a better than 50% chance it is a good combination.
If the girdle s slightly thick then you have no chance.

 

[about2Bengaged]

Garry, I''m curious as to how are you able to put "odds" on whether or not the rest of the proportions would be out-of-whack/OK/good/great.

We were also looking at a GIA-certified diamond and for all the great work they''ve done over the years, they really make it unnecessarily tough on the smart buyers here by not listing more cut information that we know they''ve already ascertained. By the way, the one we were looking at had a table of 57%, a total depth of 62.5% (that seems a bit on the high side), a thin-medium-slightly thick girdle, EX polish and VG symmetry. If it helps the proprotions of this RB are 6.13-6.16X3.84, weighs 0.90c. This doesn''t seem to be in the 1A range, but maybe 1B?

I always look forward to your insight - particularly on the first part. No need to reveal any secret sauce though.

 

[Garry H (Cut Nut)]

I use Diamcalc.

The stone you were looking at will score worse than 3 on HCA

 

[about2Bengaged]

Interesting. So I guess you entered the information I provided into DiamCalc, and that gave you angle approximations to use to get an HCA score? I do know that you can''t directly get an HCA score from the GIA certificate data.

 

[solange]

Date: 3/4/2005 3:52

3 AM
Author:CareBear
I'm looking at a RB stone with 60.1% depth and 56% table GIA ex/ex. That's all the information I have so far. Before I ask the vendor to call in the stone, what are the chances that this stone would have a crappy crown and pav angle?

Garry,

I have a RB with similar measurements to the above: depth 59.9 and table 56. The crown angle is 34.3 and the pavillion angle is 40.6. It comes out all excellent on the HCA with a score of .5.

However the girdle is medium to thick on the GIA and Sl. thick (1.4-2.2) on the OGI. Would the thickness of the girdle affect the HCA score?