Help Please! Large crown angle range!!

[mikemaz]

What is everyone''s thought on the following diamond?

I''m concerned by the very large crown angle range and pavillion angle range on the Sarin report! Should I be concerned about that or is it the averages I should look at... cause the average angles are 34 and 41 which are perfect for this table and depth.

Opinions are very very much appreciated... thanks!

GIA Certified

Round Brilliant
Weight: 1.30
Measurements: 7.09 x 7.15 x 4.29
Table: 57
Depth: 60.3
Color: H
Clarity: VS2
Symetry: Excellent
Polish: Excellent
Girdle: Thin
Culet: None
Flourescence: Strong Blue
Sarin Report:
Weight: 1.31
Diameter: 7.12mm (7.09 - 7.17)
Total Dep: 4.29 60.3%
Table: 4.03 56.6%
Crown: 34.0 Degrees (33.4 - 36.9) 14.5%
Pavil: 41.0 Degrees (40.8 - 41.2) 43.2%
Culet: 0.6% Very Small
Girdle: 1.3% (0.7% - 1.7%) (Thin - Medium)

 

[belle]

for all intents and purposes, it''s the averages that are important. do you have an idealscope image?

 

[strmrdr]

puke
pass on it.
talk about a mess....
Get an idealscope image and you will see.

No belle its not just the averages that are important.
A diamond with somewhat wide ranging angles can be ok if the angles are in the right place but that range is way too far out there.
3.5 degrees on the crown facets is way out and there is likely other things off too.
A tilted table sounds likely.

 

[strmrdr]

in this case the crown heigh could vary from 1.14mm high to 1.00mm high a total of .14mm
That is a huge variation.

tilted table?

the girdle only varies around .07mm so you are talking 2x the girdle variation.

Its huge.

 

[Maxine]

I''m wondering how it could have "excellent" symmetry??????

 

[strmrdr]

Date: 9/12/2005 9:27:03 PM
Author: Maxine
I'm wondering how it could have 'excellent' symmetry??????

All that means is that the facets meet points are small.

https://www.pricescope.com/community/threads/symmetry-meet-point-physical-optical.21444/

 

[Mara]

I agree to pass on the stone. That is a HUGE crown variation. One more acceptable would be along the lines of 34.1-34.5 or similar with an average of 34.3. The pav angle variation is fine, but that crown variation is really odd!! I''d love to see more images and an IS on that stone...!

The other thing is that the average on the crown angle is wrong. 33.6-36.9 and the average is 34? It should be more like 35. I wonder if there isn''t a typo somewhere and maybe crown is more like 33.6-34.9? Which is a bit better but average would still be more like 34.2. Puzzling!

 

[belle]

yes, strm, but i was wondering if the sarin could be off... it makes little sense that the average would be 34 when you have 33.4-36.9

that's why i wanted to see the idealscope image.

eta: posting the same time as mara....so, yes..ditto what she said.

 

[Demelza]

Date: 9/12/2005 9:45:44 PM
Author: Mara

The other thing is that the average on the crown angle is wrong. 33.6-36.9 and the average is 34? It should be more like 35. I wonder if there isn''t a typo somewhere and maybe crown is more like 33.6-34.9? Which is a bit better but average would still be more like 34.2. Puzzling!

I agree. Somewhere there''s got to be a typo. The numbers just don''t add up.

 

[Maxine]

You would have to know all 8 measurements in order to get the average......maybe more of them are on the small side....

 

[Garry H (Cut Nut)]

It would be interesting to see a Sarin 3D file (.srn) or Gemadviser / diamcalc type 3D file.

I think someone scanned the wrong stone.

 

[Maxine]

Garry, what makes you think that????

 

[valeria101]

Yeah.. something is weird there... the pavilion is so tight and even if 'excellent' symmetry means something else that still is a carefully executed cut - I can't believe those crown angles unless there is something else amiss.

If those numbers are a correct description of the stone, than it would make an interesting beast. Unless the Sarin belongs to a cushion cut or something.



[btw. this is post #9999 for me

]

 

[mikemaz]

Hi Everyone,

Thanks for everyone''s comments. That is in fact the Sarin report that I was sent... which really baffled me given the wide range in the crown of 3.5 degrees, yet the stone was measured by GIA to have Excellent symmetry.

I''ve calling to ask for a verification of the Sarin because something is just not right.

Thanks and I''ll keep you posted on what I get back. I guess such a variation could explain the price!!

PS. This is a bluenile stone and they don''t offer idealscope scans except for their signature collection.


Mike

 

[Garry H (Cut Nut)]

Interesting.
GIA have mocved to a more optical based symmetry grading and away from raw data output from Sarin!

This stone is an even wilder example
http://www.whiteflash.com/round_ideal_cut/Round-ideal-Cut-cut-diamond-798819.htm#

7 degrees of pavilion and 6.3 of crown angle variation.
But what this means is the table is tilted - you can see that the ideal-scope photo shows a very nice pattern. This 3.1 to 3.5 degrees of tTable tilt does very little to harm the optical symmetry of a diamond.

But previousl GiA gave a stone with only .8 degrees of table tilt a GOOD grade for symmetry (about 3-4 years ago).
http://www.gemology.ru/cut/english/symmetry/6.htm
There was nothing else wrong with the stone.

So GIA are malleable ?

 

[Paul-Antwerp]

Date: 9/13/2005 3:53:18 AM
Author: Garry H (Cut Nut)
Interesting.
GIA have mocved to a more optical based symmetry grading and away from raw data output from Sarin!

This stone is an even wilder example
http://www.whiteflash.com/round_ideal_cut/Round-ideal-Cut-cut-diamond-798819.htm#

7 degrees of pavilion and 6.3 of crown angle variation.
But what this means is the table is tilted - you can see that the ideal-scope photo shows a very nice pattern. This 3.1 to 3.5 degrees of tTable tilt does very little to harm the optical symmetry of a diamond.

But previousl GiA gave a stone with only .8 degrees of table tilt a GOOD grade for symmetry (about 3-4 years ago).
http://www.gemology.ru/cut/english/symmetry/6.htm
There was nothing else wrong with the stone.

So GIA are malleable ?

I think that you just found an even wilder example of incorrect scanning or of another mistake.

Brian can probably verify that.

Live long,

 

[Garry H (Cut Nut)]

Paul you can see this stone has an off center culet.
It is easily possible for symmetry to be this far out and still have a very nice stone in the ideal-scope because Brian uses our pavilion centering plastic tray.
Yopu would probably be able to detect this amount of deviation though.
I know that experianced people can not see 1 degree, but 3 degrees???

 

[mikemaz]

Hi Garry,

So given the idealscope scan for this stone... I''m assuming the one I was looking at would likely look very similar despite the 3.5 degrees range in the crown angle.

Would it be safe to expect excellent light performance from a stone like that?

I''m curious... still don''t have any update on my request for a new Sarin report.

 

[Mara]

I don''t know if that is what Garry is saying. Note where he says that experienced people cannot see 1 degree off but 3 degrees? I think that may be another matter IF that is really the case here.

But EGL Israel? Definitely not impressed! Can your jeweler get another stone or two in for you to compare it to? With more ideal specs maybe.

 

[strmrdr]

Date: 9/13/2005 12:30:27 PM
Author: Mara
I don''t know if that is what Garry is saying. Note where he says that experienced people cannot see 1 degree off but 3 degrees? I think that may be another matter IF that is really the case here.


But EGL Israel? Definitely not impressed! Can your jeweler get another stone or two in for you to compare it to? With more ideal specs maybe.

1 degree is my personal cutoff point for ideal cuts on the crown angles.
.5 on the pavilian for ideal.
The angles have to be in the right places and compliment each other for even that to work right.
Im not going to pay a premium for worse physical symmetry than that.
Super-ideals I like to see under .5 crown and .3 P but thats my personal standards not anyone elses.

not sure where egl isreal comes into the picture but they suck.

 

[Mara]

How bizarre is that, I could have sworn I saw Giangi post that this stone was from EGL Israel. I''m losin'' it!

 

[strmrdr]

Date: 9/13/2005 1:02:18 PM
Author: Mara
How bizarre is that, I could have sworn I saw Giangi post that this stone was from EGL Israel. I''m losin'' it!

welcome to my world
Iv got a good excuse whats yours hehehehehe
j/k

 

[JohnQuixote]

Hi all. I am out and about today, but called for a rescan of the .54 G VS2. Something seems wonky - may be the scan and/or leveling issues - but I don't want to declare wonk until I know for sure.

Strm, thanks for the HU.

 

[Mara]

Date: 9/13/2005 1:08:15 PM
Author: strmrdr

Date: 9/13/2005 1:02:18 PM
Author: Mara
How bizarre is that, I could have sworn I saw Giangi post that this stone was from EGL Israel. I''m losin'' it!

welcome to my world
Iv got a good excuse whats yours hehehehehe
j/k

Too much coffee!

 

[JohnQuixote]

The scan on the .54 G VS2 was indeed all a-wonk.

Here is a new one, hot off the Sarin.

 

[strmrdr]

Thanks John and the WF crew.
That looks much better.

 

[Maxine]

So if sarins can be that inaccurate......why use them?????.....it''s hard to believe it would be off that much...

 

[mikemaz]

I also got my Sarin redone and the numbers look much better. What is everyone''s opinion on this diamond now? Seems to be an excellent cut?

Sarin: Total Grade: 1
Weight: 1.306
Diameter: 7.11 (7.08 - 7.15)
Total Dep: 4.29 mm 60.4%
Table: 4.04 mm 56.8%
Crown: 33.6 (33.4 - 33.7) 14.4%
Pavilion: 41.0 (40.7 - 41.2) 43.3%
Culet: 0.6% Very Small
Girdle: 1.3% (1.0-1.5%) Thin - Medium


Thanks for everyone''s input... and the GIA results are at the top! I have to make a decision tomorrow!

 

[JohnQuixote]

Date: 9/13/2005 4:20:30 PM
Author: Maxine
So if sarins can be that inaccurate......why use them?????.....it's hard to believe it would be off that much...

Maxine - It's not usually that off. Sarin is typically accurate to within .2 This was a calibration issue - or maybe a gnat ran across the diamond during the scan.

When running dozens of scans in one sitting a 'throwaway' can occasionally happen.

Sarin is still one of the best tools at the trade's disposal, and as helium becomes popular we can reduce occurances of even that tiny .2 error.

 

[strmrdr]

Date: 9/13/2005 10:21:42 PM
Author: mikemaz
I also got my Sarin redone and the numbers look much better. What is everyone''s opinion on this diamond now? Seems to be an excellent cut?


Sarin: Total Grade: 1

Weight: 1.306

Diameter: 7.11 (7.08 - 7.15)

Total Dep: 4.29 mm 60.4%

Table: 4.04 mm 56.8%

Crown: 33.6 (33.4 - 33.7) 14.4%

Pavilion: 41.0 (40.7 - 41.2) 43.3%

Culet: 0.6% Very Small

Girdle: 1.3% (1.0-1.5%) Thin - Medium



Thanks for everyone''s input... and the GIA results are at the top! I have to make a decision tomorrow!

hca likes it.
diamcalc likes the numbers.
Normaly I dont like crown angles under 34.2 but this combo works.

should be super bright if the optical symetry is good.