Can anyone help me with the GIA cut estimator

[glamgirl]

Hi! I am having a hard time trying to use the New cut estimator the GIA has on their site.
Can anyone help me? I dont know how to change the depth to mine, and I dont know how to determine the Star% and Lower Half%.
Here are the stats:

Depth 59.1
Table 58.5%
Crown Angle 32.0
Crown Height 13.0%
Pavil Angle 40.4
Pavil Depth 42.3%
Culet 0.5%
Girdle med to thick faceted
Slight Flour
polish VG
symmetry VG


Can anyone help or give me an estimate of what cut this might be? Thanks!

 

[strmrdr]

You need the rest of the sarin info to use it.
interesting combo

 

[valeria101]

Date: 11/5/2005 10:26:09 PM
Author:glamgirl

I dont know how to determine the Star% and Lower Half%.

As far as I know, this cannot be done - they have to be measured and any lengt is feasible with any combination of crown and pavilion numbers. there''s no way to guess.

I would not venture guess thse from a picture for this purpose either - it is easy to go 1-2% off (well, overconfident here!) and that may be just the lucky point throwing the grades off...

The stats you have can yield a HCA score because that does not involve minor facets measurements. And that one comes out nice - "1.5 BIC" = something unusually lucky outside the traditional AGS winning grade and their premium.

But GIA''s cut score wouldn''t work because of the lacking minor facet numbers.

I am not sure if the results of the GIA Cut Estimator are actually precise. I suppose there is still quite a bit of leeway for the potential grade to go anywhere from the current estimate.

One thing I could guess is based on the girdle measurement: according to that webpage introducing GIA cut grades, thich girdles are not allowed into the top ''Excellent'' grade. I suppose that is a minor issue if brilliance is in place and the stone has good size for other reasons anyway. But ...

 

[strmrdr]

hca likes it:
Factor Grade
Light Return Very Good
Fire Excellent
Scintillation Excellent
Spread
or diameter for weight Excellent
Total Visual Performance 1.5 - Excellent
within BIC range

Can you get an Ideal-scope image?

 

[strmrdr]

the basic crown angles bring it in as an old ags system grade 3.

an very roughly extimated grade 6 on the new system.

Id pass and keep looking.

 

[valeria101]

Date: 11/5/2005 10:49:15 PM
Author: strmrdr

Id pass and keep looking.

Hm... have you tried it out?

I wish I knew what the symmetry is like - not being a labeled 'ideal' it may not be all that great, but there's no way to know of course. And that thick girdle could come for some fortunate tweak of the cut.


PS: Glamgirl this wasn't meant to hijack your thread... Bottom line of this post may be 'Get an IS picture' or if not 'this needs to be seen' (which are closely related, at least in my book).

 

[strmrdr]

Ana,
With perfect symmetry and several different combos of lgf% and stars DC cut grade showed low contrast and so-so light return.

Thats why it took a huge hit in the new ags system.
overall there are better combos out there.

The hca hints at the problem a bic with just very good in Light Return is a contradiction in terms.

 

[valeria101]

I shouldn''t insist, perhaps, because this ain''t mine. But, does this really bark ?

Perhaps these guys should not have left DC in the open.


There is a load of detail teaching that AGS cut grades are good etc. But there isn''t nearly as much saying that there is nothing worth looking at outside them at any cost. So... this is what I am basically asking here.

 

[strmrdr]

A good bic will score over or around 1 in brightness and around 95 ish in contrast.

It may not bark but its not the in the same class as the best cut diamonds.

A bic exists to be bright in this case you get the downside of a bic without the benefits.

 

[Garry H (Cut Nut)]

This stone would be great for a pendant or earrings.
It also will not show or be dulled by dirt as much as others.

But it is loosing some of its exceptionally large spread as a result of the thick girdle.
It might be a little dark if you look at it from very close up and block a lot of the light.