sarins on mounted stones

[lovesquares]

Hello All,

Does anyone know if a Sarin report can be generated on a fancy cut diamond that has already been placed into a setting? Can an ideal scope image be obtained from a diamond already set into a setting?

 

[Rhino]

Impossible to perform a Sarin on a mounted stone, fancy or round. An IdealScope/LightScope image is possible but will not be as accurate since it''s not loose.

 

[lovesquares]

Thanks for that info. I met an appraiser the other day (GG after his name) who did not have a Sarin machine, but claimed he could calculate a crown height % on the mounted stone. Is that possible, and if so, how accurate can that be?

 

[JC]

Well, you may have answered your own question. As you said, this appraiser said that he can calculate the crown height after the diamond has been mounted. So it must be possible. However, I would assume that you would need to take the diamond to another appraiser after his evaluation to find out if his analysis was accurate. Good luck....

 

[denverappraiser]

There are tools and techniques available to most appraisers that will allow them to estimate the crown angles to within a few degrees. In the case of a marquise cut, these angles will vary considerably depending on which facet is being described so it becomes very difficult to give a single answer. Perhaps this is what the appraiser was describing. For most uses, like applying the HCA and AGA cut grading systems, this is nowhere near enough accuracy so it really boils down to deciding what it is that you want to know

Neil Beaty, GG ISA
Independent Appraisals in Denver

 

[lovesquares]

You''ve got a point. But I''m wondering if other appraisers would agree with the statement that a crown height % can be calculated accurately, without a Sarin machine. A different appraiser didn''t think so, so who''s correct?

 

[oldminer]

When I created the AGA cut class system, I did not have a Sarin, but I could accurately measure crown height percentage. The angles not only vary around the stone, but are, indeed, harder to measure accurately.

Because I was early into this area of diamond grading and because of what needs to be measured in fancy shapes, my system uses percentages on crown and total depth for fancy shapes along with girdle thickness. Using angles just won''t work with fancy shapes.

 

[Garry H (Cut Nut)]

As Dave says, a sarin on a marquise is not much help anyway. Unless it is a Sarin (not Ogi) 3D file on the loose stone then you can ask one of us with DiamCalc to make you a GemAdviser 9see the tools section above.

then you can see a virtual ideal-scope.

Or cut to the chase and only use the ideal-scope here http://www.ideal-scope.com/using_mounted_diamonds.asp and here for fancy stones http://www.ideal-scope.com/using_fancy.asp