Why are my Sarin and Megascope readings slightly different?

[curiouscanuck]

I had a megascope report and a sarin report done on the same diamond. Why is it that they differ slightly? Is this normal? Which one is more accurate?

Thanks!

 

[dimonbob]

Both machines are the best technology available today but neither one of them are 100% accurate. You can even put a diamond on the same machine three different times and get very slightly different readings. One of these days there will be a better mouse trap but not today. Just a few years ago there was no Sarin or OGI. We who wanted to be accurate used micrometers and other measuring devices to try to get the numbers we needed. It took 20 times as long and was not near as accurate. If you are an engineer, I am sorry. We work with what we have.

 

[DiamondExpert]

Also, there are a couple of models of Sarin and OGI, and surprise, surprise, the more expensive models are more accurate & precise.

There is always potential, if not actual, variability between ANY two instruments, even if they are calibrated to the same AGS standards...that goes for comparing OGI vs. Sarin, Sarin vs. Sarin, OGI vs. OGI.

 

[Rhino]

Haha... Bob ... remember those days? I think I still have my old silhouette proportion analyzer laying around somewhere. We also had the eye piece we hooked up to the microscope. What a task it was to manually measure every crown angle, every pavilion angle... ugh. Brings back some memories. Some appraisers still use it. I know Barry Block here on LI still uses the manual methods.

Gray is correct on the various Sarin models. The most expensive version uses a camera resolution that is twice the amount as the other versions. If I'm not mistaken most models use a 320x240 rez and the most valuable version uses 3 interchangeable lens and scans the stones at 640x480 for greater and more precise accuracy as well as working with more versions of the Sarin software and offering more options. The Sarin is what AGS, GIA and all the major labs use although I am very happy with both.

Rhino

 

[curiouscanuck]

Thanks! I wasn't sure whether one was more accurate or not. But from what I'm learning, both seem to be great machines.

 

[dimonbob]

Yes, Rhino, I still have all my little (expensive) attachments that GIA sold me back in the "good old days".
My proportion analyzer that goes in the eyepiece of the microscope is gathering dust along with my slide rule. Does that date me?

I know Barry Block the "jewelry judge". It is hard to believe that he is still using the manuel method. Even a used Sarin or OGI would be better than that.