H&A stones without cut details

[Sunshines]

I came across a beautiful stone recently which has a GIA stone dated in 2004. It has no other details on angles, except the usual info on the old GIA cert :F colour VS1 1.62ct, depth 61.8, table 56, girdle Medium Ex Ex pol & Sym Flourescence faint. Two questions here :
1. because the stone has very nice H&A pattern, can I believe the jeweller''c comment that it it should be at least be a very good cut stone if not excellent as average cut stone will not have the pattern?
2. Is there any price diff for F colour stone with faint flour against another one which has none assuming all else the same? Also what''s the price diff bet GIA excellent cut stone and Very good cut ones?

 

[JohnQuixote]

Date: 4/22/2006 12:39:06 PM
Author:Sunshines
I came across a beautiful stone recently which has a GIA stone dated in 2004. It has no other details on angles, except the usual info on the old GIA cert :F colour VS1 1.62ct, depth 61.8, table 56, girdle Medium Ex Ex pol & Sym Flourescence faint. Two questions here :
1. because the stone has very nice H&A pattern, can I believe the jeweller'c comment that it it should be at least be a very good cut stone if not excellent as average cut stone will not have the pattern?
2. Is there any price diff for F colour stone with faint flour against another one which has none assuming all else the same? Also what's the price diff bet GIA excellent cut stone and Very good cut ones?

It could be cut very well...or not...from a performance standpoint: H&A (optical symmetry) is usually evidence of good craftsmanship but it’s possible to have good H&A patterning without top light performance (more here). To make even a rudimentary sight-unseen prediction we’d need depth, table, crown & pavilion angles. Minor facet info would get us farther, and an ideal-scope or ASET image would help even more. If you have the H&A images some details can be gleaned, but the best combo for internet musing is the primary numbers and supporting illustration of light performance.

With that said - from a numbers standpoint the depth/table are nice and the ex/ex in polish and lab-graded symmetry (different than optical symmetry) are promising. Top marks in finish usually indicate care was taken with the diamond. Without more info no more can be predicted, performance-wise. Frankly, if you have seen the diamond live in several lighting conditions, you are in a better position to judge it than we are here in cyberspace.

Non fluoro and faint fluoro are virtually the same, so expect no discount. Some consider all diamonds to have some level of fluoro – this is why AGS calls both non and faint “negligible” on their documents. As for pricing between GIA EX and VG: The system is still in its infancy and needs time to sort itself out. I would not expect a significant price difference, but that will vary depending on the seller and - especially - on the particular diamond.

 

[Gonzodogg]

These threads that John gets to first always just end after one reply because he is so freaking detailed. I am not complaining, I just think it is so funny every time it happens.

 

[jasontb]

John looks like my brother in law. I should try and find a picture.

 

[denverappraiser]

H&A patterning *IS* a sign of good craftsmanship. This doesn't just happen by coincidence. Tthe cutters have to go through some real effort to get it and the fact that they put in the extra effort to make the pattern is a good sign for the cutting in general. Although it’s theoretically possible to put the patterning on just about anything, I don’t recall ever seeing an h&a stone that wasn’t at least pretty good.

There’s quite a bit of debate among gemologists about the dividing line between ‘very good’ and ‘excellent’ on the GIA grading scale and whether a customer should view a grade of very good as a problem. A quick search on the forum will produce dozens of drawn out discussions on the matter. ‘Excellent’ stones are almost always lovely and ‘very good’ stones are usually lovely. How’s that for an important distinction? The GIA cut grade, at least so far, doesn’t seem to affect the price in a significant way for stones that otherwise have good light performance.

Neil Beaty
GG(GIA) ISA NAJA
Professional Appraisals in Denver

 

[Sunshines]

Thanks guys, I now have 2 choices, either go for the FVS1 with the old GIA cert but stone has ideal proportion and H&A pattern for uSD18.8k or this other stone :

DVS2 1.77 Table 58%/Depth 60.6/ girdle thin to med/Ex polish Ex Symm 7.8 -7.85 X4.77, managed to check the cut grade on GIA and It has an excellent cut. HCA score 1.4. pretty clear H&A too but price of USD23.8k.

I have a soft spot for D stones as they are rare but felt the price quoted was steep?? Can you guys help me decide? u guys think the FVS1 is more value for money? Thanks in advance.

 

[Sunshines]

sorry just to add, I got these details from the GIA cut grade check on the D stone : crown 34.5 deg, pav 40.8 deg, crown height 14.5%, Pav depth 43%, star length 55%, lower half 80%.

 

[JohnQuixote]

Date: 4/23/2006 12:58:03 PM
Author: Sunshines
sorry just to add, I got these details from the GIA cut grade check on the D stone : crown 34.5 deg, pav 40.8 deg, crown height 14.5%, Pav depth 43%, star length 55%, lower half 80%.

Great stats. Those numbers will be prime, even with GIA's rounding considered.

I've seen examples of H&A diamonds with good craftsmanship but moderate light return. They were cut to the outer limits of what many here would consider 'cherry' proportions sets. I predict the parameters above to be very safe.

 

[JohnQuixote]

Date: 4/22/2006 8:56:02 PM
Author: Gonzodogg
These threads that John gets to first always just end after one reply because he is so freaking detailed. I am not complaining, I just think it is so funny every time it happens.

LOL Gonzo. I wish I could apply more detail to things like - cleaning my desk.

Date: 4/22/2006 10:20:36 PM
Author: jasontb
John looks like my brother in law. I should try and find a picture.

Or just use mine...

 

[strmrdr]

The answer here is an IS or ASET scope.
If I cant get the numbers id want to see it under one or the other.
The only thing they might not catch is too shallow so look at the diamond up close.

Great IS or ASET image + looks good close == real real nice diamond.

With the handheld aset the red/green center color isnt a reliable indicator of pavilion angles because just a tiny bit too close or far away changes the color, it doesnt matter either way if it passes the up close viewing test.

The Beginner IS Scope is only $25....
The ASET is $105
so the IS makes more sence for a one time use.

 

[JohnQuixote]

Date: 4/23/2006 1:23:13 PM
Author: strmrdr

The answer here is an IS or ASET scope.
If I cant get the numbers id want to see it under one or the other.
The only thing they might not catch is too shallow so look at the diamond up close.

Great IS or ASET image + looks good close == real real nice diamond.

With the handheld aset the red/green center color isnt a reliable indicator of pavilion angles because just a tiny bit too close or far away changes the color.

Supporting illustration of light performance =

 

[Sunshines]

Thanks everyone, appreciate all the help!