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 Post subject: Scale Precision for Measuring Specific Gravity for Gem ID
PostPosted: Sun Jan 19, 2014 10:09 pm 
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Joined: Sat Jul 06, 2013 8:34 pm
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If purchasing a scale for the purpose of measuring specific gravity to aid in gem id, how precise does the scale need to be? I see scales that measure to .01 and also to .001. Obviously, the .001 scales are much more expensive. So...how important is that difference in precison to measuring specfic gravity?

Many thanks from this newbie!


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 Post subject: Re: Scale Precision for Measuring Specific Gravity for Gem I
PostPosted: Mon Jan 20, 2014 6:19 am 
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Joined: Wed Sep 15, 2010 4:12 am
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Location: Belgium
http://www.prettyrock.com/php/specific- ... ations.php

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http://www.gemsdat.be/engels.htm


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 Post subject: Re: Scale Precision for Measuring Specific Gravity for Gem I
PostPosted: Mon Jan 20, 2014 12:08 pm 
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Joined: Sun Oct 16, 2005 12:22 pm
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Location: San Francisco
While we are on the subject of Pretty Rock.
They make a very reliable SG unit for $89 complete with scale.
http://www.prettyrock.com/php/product-d ... nts.php%3F

Of course I was skeptical about the accuracy of this little understated tool, so I checked it with several GIA graded diamonds.....it was 100% accurate.

The unit is made for smaller samples, not large pieces of rough, but I have found it to be one of the handiest tools in my SG arsenal.


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 Post subject: Re: Scale Precision for Measuring Specific Gravity for Gem I
PostPosted: Mon Jan 20, 2014 1:50 pm 
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For stones that are 3g (15ct) or more you can use a 0.01g scale, but for lighter stones stick to 0.001g (or 0.002g) scales. I use Tanita scales (great quality)


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 Post subject: Re: Scale Precision for Measuring Specific Gravity for Gem I
PostPosted: Mon Jan 20, 2014 2:21 pm 
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Joined: Mon May 14, 2007 11:00 am
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Location: Monterey, CA
All the above is true if you plan to use a "scale".

On the other hand, if you use a beam balance, you don't need any weights or calculations. You can measure any stone from 10 kilo to 10 points without doing any arithemetic. And, you can build it yourself. :D :D


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 Post subject: Re: Scale Precision for Measuring Specific Gravity for Gem I
PostPosted: Tue May 13, 2014 5:59 am 
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Joined: Sat May 10, 2014 5:09 am
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Why not you search one on EBay and Amazon with requirement that you need. Because there are many scales which are available with different price range and precision level. And hope you get a cheap one with maximum accuracy there.And most of animal and Vet Scales that are available there have more accuracy as they are made for finding really small measurments.


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