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 Post subject: Seperating Saltwater and Freshwater Pearls
PostPosted: Tue May 08, 2012 4:20 am 
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Tip from Dr. Henry Hanni:
To test a pearl to determine if it is fresh or salt water (which has become more difficult as the Chinese Freshwater are getting more sophisticated), we can rely on the additional manganese all freshwater pearls contain.
The manganese content of freshwater pearls is 3X greater than salt water.

Using Manganese test strips (inexpensively available online) and some diluted hydrochloric acid we can test for Mn content.

As I understand it, we drop a wee amount of diluted hydrochloric on the pearl. According to Dr. Hanni, the pearl will not be damaged. Swipe the Mn Test strip over the area and if it tests positive for Mn, you have a freshwater pearl.

Our member Earthling, aka Oliver said he would do a little further research and testing on this and report back.


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 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Tue May 08, 2012 5:50 am 
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Wow! thank you Barbra for this tip!
How many part per milion (ppm) of concentration of the strips test it will be used?
And the concentration of HCL? 10%?

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 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Tue May 08, 2012 6:03 am 
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This strips detect a range of ppm...

from 0.02 to 2 ppm

http://www.filtersfast.com/Sensafe-Manganese-Filter-Check.asp

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 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Tue May 08, 2012 11:16 am 
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Earthling should be back home and settled shortly.
I'm sure we'll hear back.
We both heard the PEARL lecture by Dr. Hanni at the Scottish Gemmological Conference.
He spoke of the test rather quickly, like we'd all just "get it".


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 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Wed May 09, 2012 3:35 pm 
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Hi

the solution used is HCL 10%, the test will just indicate the type of pearl if it will show color on the stripe to one of the ends, either minimum or maximum level.
Everything in between will not be diagnostic since it could be a freshwater pearl that was grown in an estruary with saltwater content and therefore the mangan level would be higher.
I will order one of the tests and give it a go to work and report back.

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 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Wed May 09, 2012 4:02 pm 
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10% HCl sounds quite aggressive. What about something softer such as white vinegar?

Note that a little bit of remaining acidity can be harmful with time (especially in a porous material which will retain traces of acid in the pores). Here's what people usually do with minerals after acid has been added: first they thoroughly rince the sample with water, and then they proceed to neutralisation by soaking it in a saturated solution of sodium bicarbonate, and then they rince it again with distilled water.
I would suggest training on some value-less samples first.


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 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Wed May 09, 2012 4:12 pm 
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The test will be sure to some degree a destructive one, but as said this is just something that is still in its baby-shoes and have to be developed until it can be used properly.

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 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Wed May 09, 2012 9:53 pm 
Interesting... sure will come in handy sometime... thank you Barbra :D


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 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Thu May 10, 2012 9:39 am 
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Thanks Barbra Voltaire, it's really very informative post.

with best regards

HUK

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 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Thu May 10, 2012 10:00 am 
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What we need to do, is a little experimentation with some "crap" pearls to check on the reliability of the process and whether or not we can detect any damage to our test pearls.


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 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Thu May 10, 2012 11:11 am 
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Boy! Have I got a "crap" pearl for you :lol: . It's a FW pearl that developed at the shell and shows the insides on a couple of "sides" of the pearl. Let me know if you'd like a photo and if it could be of service 8) .

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 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Thu Aug 02, 2012 7:06 pm 
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Just curious. Did anything come of these tests?

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 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Thu Aug 02, 2012 8:05 pm 
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I never heard anything ... and I still have the "crap" pearl that could be sacrificed :twisted: .

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 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Thu Aug 02, 2012 10:32 pm 
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I wonder if earthling got around to further testing....hope he sees this.


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 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Fri Aug 03, 2012 3:17 am 
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i purchased the strip kit but still didn't had the time for test....... :( :( :(

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