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 Post subject: garnet vs ruby
PostPosted: Wed Jan 08, 2014 12:16 pm 
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Does anyone know how accurate it is when using a neodymium magnet to seperate ruby from garnet?


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 Post subject: Re: garnet vs ruby
PostPosted: Thu Jan 09, 2014 1:30 am 
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The best source for magnetic information is here
gemstonemagnetism.com/

Personally, i would not reach for a magnet for separation.


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 Post subject: Re: garnet vs ruby
PostPosted: Thu Jan 09, 2014 12:43 pm 
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Ok I'll check it out thanks! And yeah its more of a last resort for me... I guess I'll have to just buy a ruby for comparison. I read about what they are supposed to look like under a filter but I'm just not sure.


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 Post subject: Re: garnet vs ruby
PostPosted: Thu Jan 09, 2014 12:49 pm 
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I wouldn't reach for a filter either.

Refractive index (to identify the mineral) and microscopic observation (to separate natural from synthetic) is how you need to proceed. :D


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 Post subject: Re: garnet vs ruby
PostPosted: Thu Jan 09, 2014 6:45 pm 
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Lol failed again :) I took readings with the refractometer some were for sure garnet but there were a few that fell in the middle. That's why I was looking for different ways, I'm pretty sure they are all garnet but I want to be positive bc they are a decent size and also I want the satisfaction of knowing for sure lol :) I didn't get a microscope yet bc I'm not going to buy anymore mixed gem parcels... Huge waste of time and money :/ I found good suppliers for anything I need now. Sorry I got wayyy off track, I was going to ask if rubies or garnets show a double line on the refractometer or if that's just the fluid line near the gem line? Or is that from placement on the refractometer? This is just tuff for me, bc I've yet to look at a ruby on the meter... I do know that these are all natural though :) Whatcha think? Thanks for the help so far!


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 Post subject: Re: garnet vs ruby
PostPosted: Fri Jan 10, 2014 1:04 am 
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How much experience do you have using a refractometer?
The separation is straight forward.


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 Post subject: Re: garnet vs ruby
PostPosted: Fri Jan 10, 2014 10:02 am 
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Not much at all


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 Post subject: Re: garnet vs ruby
PostPosted: Fri Jan 10, 2014 11:32 am 
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Ok I just went back and read the article on refractometers. I'm going to give it another go ton and I'll post my findings after. Thanks for the help Barbara


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 Post subject: Re: garnet vs ruby
PostPosted: Fri Jan 10, 2014 11:34 am 
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The garnet group is singly refractive, rubies (corundum) is doubly refractive.
Are you using a monochromatic filter or light source with the refractometer?
Did it come with a polarized plate?

Have you watched Starla Turner's tutorial on How to Use a Refractometer?
http://gemologyonline.com/Forum/phpBB2/ ... 37&t=15491


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 Post subject: Re: garnet vs ruby
PostPosted: Fri Jan 10, 2014 12:17 pm 
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No I just found this site a couple weeks ago so I haven't looked at everything yet, I will though! The meter has an internal led and polarized lens, it is a cheap china meter though :/ but from what I read I think I've got it now, if it shows 2 different readings from the same position (normal/polarized) its dr which in my case would indicate ruby right?


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 Post subject: Re: garnet vs ruby
PostPosted: Fri Jan 10, 2014 5:19 pm 
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No.
One must turn the polarized plate to get the readings.
I think Starla covers this.
What refractive index are you getting?


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 Post subject: Re: garnet vs ruby
PostPosted: Fri Jan 10, 2014 11:39 pm 
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So I'm having trouble with turning the polarizing eye piece, I can't see any change really. It may just be inferior equipment? The eye piece won't screw into the viewer so I have to hold it and spin it. Anyway I took a picture of my measurements with the corresponding stone I'll try to post it in a bit I'm on my phone now. The lower end measurements were around 1.759 for a couple and a few were in the 1.762 range.


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 Post subject: Re: garnet vs ruby
PostPosted: Fri Jan 10, 2014 11:53 pm 
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Where do you live, j.mcgee_1985?
Maybe a forum member can have a look at your mystery stone and your refractometer.

In the meantime, do you have a gem you are 100% sure of? Perhaps an amethyst or spinel. Take an RI on it.

Is the instrument giving you expected results?


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 Post subject: Re: garnet vs ruby
PostPosted: Sat Jan 11, 2014 12:18 am 
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heres the picture with what i measured so far, i'm thinking just the ones on the top left are rubies they looked to be right around 1.766 but never went higher than 1.769 maybe 1.768 i'm kinda tired so it was hard judge. but i think i understand what you meant when you said
Barbra Voltaire wrote:
How much experience do you have using a refractometer?
The separation is straight forward.
the ones in the top left were right between 1.760 and 1.770 my guestimating might be a little off but i feel good about those ones. and i live in shawnee, oklahoma about 30 mins from oklahoma city. no need to look at the meter i know its not a quality one now by price comparison, but its what i could afford at the time.


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 Post subject: Re: garnet vs ruby
PostPosted: Sat Jan 11, 2014 1:34 pm 
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update as of this morning there are quite a few that measure in 1.768-1.770 range a couple in the 1.766-1.768 range so those are all rubies right? i'm basing this off the gemology project ri figures. let me know what you think.


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