Unusual Diamond Proportions

[FB.]

This diamond has a rather larger table, flatter crown and shallower depth than what seems to be "normal", but seems to score fairly well on the cut grade.
GIA = Very Good
HCA = 2.9

Here are the vital stats:

Table - 63%
Crown angle - 30.5’
Crown Height - 11.0%
Pavilion angle – 41.2’
Pavilion depth – 43.5%
Star – 60%
Lower half – 85%
Girdle – medium to slightly thick / 3.5%
Culet - none
Polish – very good
Symmetry - good
Total Depth - 57.8%

I would appreciate opinions on any hidden "pro''s and con''s" of the more unusual dimensions such as these.

Thanks,
FB

 

[stone-cold11]

Any images?

 

[FB.]

Sorry, no images.

I was trawling a few "virtual" diamonds and happened to notice such a flat crown and thought that I''d put the vitals into the HCA.

Knowing that GIA often overstate cut grade (with many GIA "EX" obtaining mediocre scores on the HCA or AGS system), I thought that this stone might have a truly awful HCA score, but I was rather surprised.

 

[Rockdiamond]

I''m with stone on this one.
I never judge diamonds solely on specs- but even I would question the 63% table on a round diamond.
This one needs to be eyeballed by someone you feel comfortable with- and photos too.

 

[Lorelei]

It could be a brilliant diamond but not do much else in the way of fire, I would imagine it gives a bit of a flash and bang like a one trick pony. It could also show a fish eye which is not desirable. Do you have the diameter in MM?

 

[Dancing Fire]

flat crown + large table + a shallow cut =

 

[Kaleigh]

I want to see some pics!! That would be educational.. But am with Lorelei on this one...

 

[strmrdr]

interesting diamond.
Using those base numbers if everything was perfect it would not be a fisheye.
Brightness would be about the same as an ideal cut
Fire would suffer a lot however.
Here is what an IS image for such a diamond could potentially look like.

 

[Lorelei]

Date: 7/29/2009 1:20:22 AM
Author: strmrdr
interesting diamond.
Using those base numbers if everything was perfect it would not be a fisheye.
Brightness would be about the same as an ideal cut
Fire would suffer a lot however.
Here is what an IS image for such a diamond could potentially look like.

Kewl!

 

[FB.]

Lorelei

Dimensions:

Depth: 3.86mm
Diameter: 6.70-6.66mm

 

[Lula]

Date: 7/29/2009 1:20:22 AM
Author: strmrdr
interesting diamond.

Using those base numbers if everything was perfect it would not be a fisheye.

Brightness would be about the same as an ideal cut

Fire would suffer a lot however.

Here is what an IS image for such a diamond could potentially look like.

I love these images that you create from the dimensions, Storm, very educational.

 

[FB.]

Thanks for the replies - especially strmrdr for the IS simulation.

Question for strmrdr (although I''d be keen to hear comments from anyone.....)

The HCA gives the following:

Light Return Very Good
Fire Good
Scintillation Good
Spread or diameter for weight Excellent
Total Visual Performance 2.9 - Very Good - Worth buying if the price is right

.....................

You mention that "Fire would suffer a lot".
Do you think that fire would be below the "good" category that the HCA estimates?
Would an "open" mounting (say 4-claw) allow light entering the sides/bottom of the stone to compensate for the shortfalls?

 

[strmrdr]

Date: 8/2/2009 3:56:26 PM
Author: FB.

The HCA gives the following:



Light Return Very Good

Fire Good

Scintillation Good

Spread or diameter for weight Excellent

Total Visual Performance 2.9 - Very Good - Worth buying if the price is right


.....................


You mention that ''Fire would suffer a lot''.

Do you think that fire would be below the ''good'' category that the HCA estimates?

Would an ''open'' mounting (say 4-claw) allow light entering the sides/bottom of the stone to compensate for the shortfalls?

I think the hca fairly rates it based on the numbers.
No, if it is well cut with those numbers the setting wont matter much.
Keep in mind I and the hca have no way of knowing how well the actual diamond is cut.
The opinions are best case.
I have seen a lot of wide tabled rounds and they can look ok in pendants but I don''t think I would personally put one in a ring.

 

[FB.]

Thanks, strmrdr.