GIA excellent steep deep diamonds:

[cubiczirconia]

How common is it to find steep deep diamonds appraised with an excellent cut grade by GIA?

 

[Lorelei]

Date: 8/27/2008 11:03:11 AM
Author:cubiczirconia
How common is it to find steep deep diamonds appraised with an excellent cut grade by GIA?

Cubic, this thread might help - https://www.pricescope.com/community/threads/gia-ex-let-the-buyer-beware.41371/

 

[John P]

Date: 8/27/2008 11:03:11 AM
Author:cubiczirconia

How common is it to find steep deep diamonds appraised with an excellent cut grade by GIA?

Diamonds are typically cut to proportions which will retain the most weight possible from the rough. This could be shallow, steep or otherwise depending on the rough and the plan. In many cases there is more weight recovery when cutting a diamond deep.

Manufacturers know, prior to sending a round brilliant to GIA, what cut grade it's likely to receive. If they can plan for maximum weight recovery that still falls within GIA EX it makes economic sense to cut there. Unfortunately GIA got a bit liberal on that side of their EX grade.

It should be said that what = "steep/deep" varies, depending on who you talk to. In trade terms "steep/deep" is a lot steeper and deeper than the stones assigned that nickname on Pricescope.

Here are some basic guidelines for the typical RBs we see advertised through PS: If the pavilion angle is > 41 it bears a further look... Paired with some crowns they can be beautiful but a crown too steep will cause visible leakage. Alternately, a steep crown should be paired with an appropriately shallow pavilion angle for good light return.

If you're considering diamonds online the HCA good for disqualifying deep stones. It's tough in the 41 PA range but, as it's maker explains, diamods in the 2-3 area can look good depending on optical symmetry, brillianteering, etc...which an ideal-scope can help reveal.

 

[Dancing Fire]

Date: 8/27/2008 11:03:11 AM
Author:cubiczirconia
How common is it to find steep deep diamonds appraised with an excellent cut grade by GIA?

i've seen a few EX,EX,EX with 41.3' x 35.5' x 44% pav depth combo.

 

[strmrdr]

My experience looking locally its better than 1/2
nice thing is you can quickly weed them out using the HCA or a dealer who knows what they are doing.
There are a lot of 41/35s GIA EX with rounded numbers on the report out there that can be awesome or just so-so and those you need an IS on.
The GIA rounding makes them impossible to judge by the GIA numbers.
I suspect that more than one cutting house has chosen that as the GIA EX target and done right its a good one.