pavilion angle variances

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

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....

Date: 2/26/2005 32:53 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.

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

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

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

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

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 :)

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


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