pavilion angle variances

[TLS]

I know that the average pavilion angles provided from a sarin is what many of us use to help us determine how well cut our diamond is. Can someone give me an example of what is considered an acceptable range/variance for ideal cut RB diamonds. How tight are the ranges/variances usually for ideal cuts, for example 40.6 - 40.9 etc, or would that be unlikely, would most ideal cut diamonds have a broader range such as 40.6 -41.0 or something like that?

Could someone give me an example of what a preferred range would be, I assume the "tighter" the specs the better, so what would be considered acceptable and what would be considered not acceptable.

I am also curious about the same info on crown angles.

Thanks

 

[niceice]

Date: 2/25/2005 10:48:19 PM
Author:TL1
I know that the average pavilion angles provided from a sarin is what many of us use to help us determine how well cut our diamond is. Can someone give me an example of what is considered an acceptable range/variance for ideal cut RB diamonds. How tight are the ranges/variances usually for ideal cuts, for example 40.6 - 40.9 etc, or would that be unlikely, would most ideal cut diamonds have a broader range such as 40.6 -41.0 or something like that?

Could someone give me an example of what a preferred range would be, I assume the ''tighter'' the specs the better, so what would be considered acceptable and what would be considered not acceptable.

I am also curious about the same info on crown angles.

Thanks

Correct, the tighter the range between the high and low variances that determine the average angle stated on the Sarin report the better... For instance, an average pavilion angle of 40.8 degrees that is based on a high of 41.0 and a low of 40.6 is fabulous and even something a little broader like 41.1 to 40.5 is not so bad, but we''d avoid something like a low of 40.3 degrees and a high of 41.3 degrees if something cut tighter was available... Especially if the variance occurred one facet step apart from the other as we saw in some of the production that we rejected a few months ago, the extreme drop so close together had a significant effect (decrease) in the measured light return of the stones... Personally, we''re quite fond of the combination of a crown angle between 34.3 - 34.8 degrees with a pavilion angle between 40.6 - 40.9 degrees, but there are other combinations that work well...

 

[Dancing Fire]

here''s an example of a tightly cut stone that i bought from GOG....notice the min and the max on the specs.

http://www.goodoldgold.com/sarinfiles2003/BR334HSI1-12753038DIAM.srn

 

[TLS]

Thanks for your responses!

Dancing fire I couldn't pull up the attachment for some reason and I tried to find it on GOG's website in the "sold for educational purposes" but couldn't locate it...

Does anyone know why most sarin reports don't show diagrams of all the angles. for example mine has a diagram showing the crown angles but then doesn't show a diagram of the pavilion angles, I wanted to see the diagram so I could see every angle and exactly where it fell. Is that not typically supplied? I know I am very anal....

 

[Dancing Fire]

Date: 2/26/2005 1:26:13 AM
Author: TL1
Thanks for your responses!

Dancing fire I couldn''t pull up the attachment for some reason and I tried to find it on GOG''s website in the ''sold for educational purposes'' but couldn''t locate it...

Does anyone know why most sarin reports don''t show diagrams of all the angles. for example mine has a diagram showing the crown angles but then doesn''t show a diagram of the pavilion angles, I wanted to see the diagram so I could see every angle and exactly where it fell. Is that not typically supplied? I know I am very anal....

TL1
click on the link ,go to the top and then point at the shield and click on allow blocked content.. and then click yes. and then on the top left hand corner click the word detail, and it''ll say summary. click the pull down box to ags minimum maximum sym and that will show you the complete detail of the stone. btw, what certification does your stone come with?

 

[Garry H (Cut Nut)]

The variance in crown and pavilion angles can, and often is a result of a tilted table or dust on the scanner stage.

If you can examine a H&A''s or ideal-scope photo you can completely ignore the scan data.

A variance of more than 1 degree can mean didly squat, and a variance of 0.2 degrees can be worse.

Even more important is the azimuth or direction the facets face - and this type of deviation is usually corrected by most scanners to be non exxistant.

 

[Dancing Fire]

Date: 2/26/2005 3

2:53 AM
Author: Garry H (Cut Nut)
The variance in crown and pavilion angles can, and often is a result of a tilted table or dust on the scanner stage.

If you can examine a H&A''s or ideal-scope photo you can completely ignore the scan data.

A variance of more than 1 degree can mean didly squat, and a variance of 0.2 degrees can be worse.

Even more important is the azimuth or direction the facets face - and this type of deviation is usually corrected by most scanners to be non exxistant.

cut nut
so... what you''re saying is, the sarin specs are useless?

 

[TLS]

Dancing fire, I got my stone from GOG too and it is a very beautiful sparkly stone. I was just paranoid because one of the sarin''s I had showed a pavilion angle range of 40.6 - 41.2. Being numbers concscious i was paranoid about seeing that 41.2 measurement. the avg was 40.9, but I don''t what each individual angle was.

The stone was very brilliant & sparkly to me, but I unfortunately didn''t get the opportunity to compare it to many other ideals to see differences among a top bunch of stones (no one locally had anything near this quality).

Jonathan has a reputation for selling very nice quality stones, so I am sure there isn''t any issue....I think the IS image showed a teeny bit of leakage that garry said did not appear to be any kind of problem - but I am wondering if it was because of 1 or 2 of the pav. angles getting into the 41 range (since I didn''t get a diagram with the pavilion angles I don''t know what each was). I am very detail oriented, so this type of stuff drives me crazy after a while - I obsess

 

[Lynn B]

Date: 2/26/2005 4:21:42 PM
Author: Dancing Fire

Date: 2/26/2005 3

2:53 AM
Author: Garry H (Cut Nut)
The variance in crown and pavilion angles can, and often is a result of a tilted table or dust on the scanner stage.

If you can examine a H&A''s or ideal-scope photo you can completely ignore the scan data.

A variance of more than 1 degree can mean didly squat, and a variance of 0.2 degrees can be worse.

Even more important is the azimuth or direction the facets face - and this type of deviation is usually corrected by most scanners to be non exxistant.

cut nut
so... what you''re saying is, the sarin specs are useless?

I''m not Garry, and I wouldn''t even presume to speak for him - but here''s my take on what he said. A sarin is just another "report" on a diamond... and when you are buying "sight unseen", all reports are valuable and play an important role in determining the potential performance of a stone. It''s sooooo easy to get so hung up on the "right numbers" (especially here in PSville!) -- but none of the reports/tests/tools are truly conclusive on their own. And all of them have potential shortcomings. The final determining factor should always be human eyes. Just my humble 2 cents.

Lynn

 

[JohnQuixote]

Date: 2/26/2005 4:21:42 PM
Author: Dancing Fire

Date: 2/26/2005
Author: Garry H (Cut Nut)

The variance in crown and pavilion angles can, and often is a result of a tilted table or dust on the scanner stage.

If you can examine a H&A's or ideal-scope photo you can completely ignore the scan data.

A variance of more than 1 degree can mean didly squat, and a variance of 0.2 degrees can be worse.

Even more important is the azimuth or direction the facets face - and this type of deviation is usually corrected by most scanners to be non exxistant.

cut nut

so... what you're saying is, the sarin specs are useless?

DF, they are part of the equation.
Those averages are telling in the overall, thus the popularity of Sarin report.

But when splitting hairs, the IS image does say more about light return than Sarin numbers. The H&A images say more about precision of patterning.

As for variances, we've noted that when the angles of opposite facets averages the listed overall average for that angle the performance is not adversely influenced like when there are random smatterings of wide variance around the clock.

 

[Dancing Fire]

Date: 2/26/2005 4:35:21 PM
Author: TL1
Dancing fire, I got my stone from GOG too and it is a very beautiful sparkly stone. I was just paranoid because one of the sarin''s I had showed a pavilion angle range of 40.6 - 41.2. Being numbers concscious i was paranoid about seeing that 41.2 measurement. the avg was 40.9, but I don''t what each individual angle was.

The stone was very brilliant & sparkly to me, but I unfortunately didn''t get the opportunity to compare it to many other ideals to see differences among a top bunch of stones (no one locally had anything near this quality).

Jonathan has a reputation for selling very nice quality stones, so I am sure there isn''t any issue....I think the IS image showed a teeny bit of leakage that garry said did not appear to be any kind of problem - but I am wondering if it was because of 1 or 2 of the pav. angles getting into the 41 range (since I didn''t get a diagram with the pavilion angles I don''t know what each was). I am very detail oriented, so this type of stuff drives me crazy after a while - I obsess

TL1
i got 6 different set of specs from 6 different machines.the HCA scores between 1.1-1.8 depending on which set of specs i use.

 

[Dancing Fire]

Date: 2/26/2005 4:44:33 PM
Author: Lynn B

Date: 2/26/2005 4:21:42 PM
Author: Dancing Fire

Date: 2/26/2005 3

2:53 AM
Author: Garry H (Cut Nut)
The variance in crown and pavilion angles can, and often is a result of a tilted table or dust on the scanner stage.

If you can examine a H&A''s or ideal-scope photo you can completely ignore the scan data.

A variance of more than 1 degree can mean didly squat, and a variance of 0.2 degrees can be worse.

Even more important is the azimuth or direction the facets face - and this type of deviation is usually corrected by most scanners to be non exxistant.

cut nut
so... what you''re saying is, the sarin specs are useless?

I''m not Garry, and I wouldn''t even presume to speak for him - but here''s my take on what he said. A sarin is just another ''report'' on a diamond... and when you are buying ''sight unseen'', all reports are valuable and play an important role in determining the potential performance of a stone. It''s sooooo easy to get so hung up on the ''right numbers'' (especially here in PSville!) -- but none of the reports/tests/tools are truly conclusive on their own. And all of them have potential shortcomings. The final determining factor should always be human eyes. Just my humble 2 cents.

Lynn

Lynn
i agree sarin is just one piece of the puzzle.here are the steps i would take when buying a stone online.

1-talk to the vendor about the stone and get his/her opinion.
2-get all the information that is available,high tech/low tech,pictures,etc...
3-send it to an appraiser(ask alot of questions) and get his/her opinion.
4-if all teh above sounds/looks promising, then i want see the stone myself.