New Mineral Named After GIA’s John Koivula
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 Post subject: Slight error in SG video
PostPosted: Mon Jul 30, 2007 5:30 pm 
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Dont know where to post this, but I believe this is a good place for my question.

I looked at the video regarding SG and it looked okey until the stone was immersed in water by using the hand. To get an accurate reading that should be avoided by using a stoneholder, yes, like she did when she put the stone on the scale in the first place... avoiding dirt/grease/fat from fingers should be a priority... yes?

I hope you take this criticism positively.


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PostPosted: Mon Jul 30, 2007 7:01 pm 
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Speaking as the person who made the video, I can say using tweezers certainly can't hurt.
I will clean a gem very thoroughly BEFORE beginning any testing.
I know that my readings are usually quite accurate. Sometimes I drop the stone in with my hands other times I'll use tweezers. Depends what is more convenient. You'll notice the SG that I got with the demonstration video was correct....there was NO error with the result.

If you use a lot of lotions, or have sweaty, dirty, mucky hands use tweezers. .


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PostPosted: Tue Jul 31, 2007 11:50 am 
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Indeed, your video is nice, but I just thought it would be even nicer to tell the viewer that to obtain a good reading (esp. more important if you do not have such a good instrument as you used in the video) that grease/dirt is not good when trying to obtain a SG reading, that you should clean the stone BEFORE as you stated. I just miss that info in the video else it is nice as i mentioned earlier.....
:)


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PostPosted: Tue Jul 31, 2007 12:02 pm 
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Hi,

Maybe that should be mentioned in the text somewhere.
For a stone of that size the error in calculations is marginal and has little effect.

Thanks for pointing that out.


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