Sophistication of a Sarin machine

[Spear]

When determining the average girdle diameter, the girdle is measured in several differend directions.
The biggest and smallest measurements are taken and divided by two.

In a laboratory certificate, is this calculation made by a grader or does the sarin machine make the calculation automaticly.

 

[Rhino]

I believe in the GIA/GTL its still done manually. If someone knows different correct me if I''m wrong.

 

[Dancing Fire]

Date: 5/12/2005 10:39:48 PM
Author: Rhino
I believe in the GIA/GTL its still done manually. If someone knows different correct me if I''m wrong.

Rhino
i thought GIA runs a sarin scan on every stone.why would they need to do it manually.

 

[niceice]

Date: 5/13/2005 1:01:47 AM
Author: Dancing Fire

Date: 5/12/2005 10:39:48 PM
Author: Rhino
I believe in the GIA/GTL its still done manually. If someone knows different correct me if I''m wrong.

Rhino
i thought GIA runs a sarin scan on every stone.why would they need to do it manually.

They run a Sarin on every stone, but it is my recollection as well that the GIA still relies on manual measurement of the girdle - perhaps only because they have always done it that way?

 

[Garry H (Cut Nut)]

GIA GTL has made it a secret, but Marty Haske has studied results and believes they use mm''s not % (as AGS does).

for eg 0.15mm might be medium for a .30ct and a 3ct and a 30ct, wher as it would be thick, medium and thin for AGS

this is the link i think http://www.gis.net/~adamas/cut.html#girdle

 

[Garry H (Cut Nut)]

R&T, labs do not measure stones - they scan them on the Sarin - the measurements for diameter and depth etc come from the scan - they call it "non contanct optical measurement device"

 

[niceice]

Date: 5/13/2005 1:42:12 AM
Author: Garry H (Cut Nut)
R&T, labs do not measure stones - they scan them on the Sarin - the measurements for diameter and depth etc come from the scan - they call it ''non contanct optical measurement device''

Manual measurement might be the wrong term, perhaps manual calculation is more correct. During a conversation with Fred Fish at Sarin or Marty Haske and I can''t remember which at the moment, we were discussing the variance between the Sarin results for the girdle measurements and the description of the girdle on the GIA lab reports and I seem to recall that the explanation revolved around something along the lines of the GIA manually calculating the measurement as opposed to merely accepting the results of the Sarin... Something about the GIA thought that the girdle measurement should be determined by measuring one section of the girdle and Sarin felt that it was more accurately measured a different way and the difference of opinion defined the reason for the difference in how the girdle measurements appeared... You probably know the answer to this off the top of our head Garry, but for the life of me I can''t remember what it is at the moment, just the concept behind the conversation... It''s freak''n late and I''m going to bed

 

[Garry H (Cut Nut)]

ha ha ha - it is just on time for me to go home and have a 1 hour bath with hor douveres thingy m''bobs and a nice glass of something in the friday night ritual before dinner out with friends.

R&T - rad the link in my post above - it would have been Marty you spoke with - and all is explained there.

 

[oldminer]

Sarin and Ogi devic es are generally pretty much accurate enough for what is being asked of them. Every so often they do not obtain an accurate measurement for some reason. Occasionally they can also require some recalibration, too.

A good lab measures certain features which may be the weakest measurements obtained from these devices in order to give the best possible product to the end user. It makes sense to double check automated measures and grading as it adds to accuracy. And, accuracy is what everyone wants when it comes to diamond reports, right? There is no agenda here, but just obtainign the right measures in the end that count.