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 Post subject: Refractometer on doublets
PostPosted: Fri Nov 19, 2010 7:30 am 
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Hey this is probably a dumb question ,On cut stones what happens to the refractometer reading on a doublet if the top is glass and the bottom is say corundum,or a triplet with a thin slice of whatever in the girdle and composed of whatever else ,its not in my syllabus book for first year. Will a refractometer only read the surface in contact with the slit on CUT stones or from refraction will it go haywire because of the composites, obviously i dont have a doublet or composite to play with.


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 Post subject: Re: Refractometer on doublets
PostPosted: Fri Nov 19, 2010 8:53 am 
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It will only read the surface in contact. You can do a reading on the top and one on a facet of the bottom.

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 Post subject: Re: Refractometer on doublets
PostPosted: Fri Nov 19, 2010 10:58 pm 
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Thanks Marcm ,ive been buying alot of antique jewelry lately and have found some obvious composites and some not so ,one of the only tests i can do without taking the set gem out is refraction ,but this is of little help on set stones.The shop owner has a electronic hardness indicator so i will poke and prod all sides and pavillion too.


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 Post subject: Re: Refractometer on doublets
PostPosted: Sat Nov 20, 2010 12:37 am 
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Joined: Sun Oct 16, 2005 12:22 pm
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Location: San Francisco
What's an electronic hardness indicator.
Never heard of it.


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 Post subject: Re: Refractometer on doublets
PostPosted: Sat Nov 20, 2010 3:29 am 
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Sorry Barbra :oops: for my poor terminology but i just dont know what else to call it, i'll try again, you know those electronic diamond testers that squeal at you and arn't really a reliable instrument anyway i guess a better term might be electronic density tester?,maybe they work on high frequency absorbtion or resonation inside a gem to hazard a guess of hardness or density depending on conduction, and its general relationship to specific gravity in gemstones(not in Metals as we know),well thats not strictly right either as they dont say the digital scale has anything to to with hardness, but diamond is the top scale and naturally glass tests toward the bottom, logically to my mind that is how i guess they operate ,so not a hardness tester as such but are sold as a diamond tester and can be easily fooled by simulants. Sorry for my rudimentary explanations and descriptions ,i am trying though. :oops:


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 Post subject: Re: Refractometer on doublets
PostPosted: Sat Nov 20, 2010 3:36 am 
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Diamond testers measure thermal conductivity.
I think your entire premise may be incorrect, lightspeed.


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 Post subject: Re: Refractometer on doublets
PostPosted: Sat Nov 20, 2010 4:05 am 
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No not Entirely!! ,i did guess conductance of some sort,Thats why im in the beginners section.
Thankyou for your correction


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