URAL MINERALOGICAL FESTIVAL, July 3 to 21, 2019, in Yekaterinburg City, Ural region, Russia
Welcome to the GemologyOnline.com Forum
A non-profit Forum for the exchange of gemological ideas
It is currently Sat Jun 15, 2019 6:41 pm

All times are UTC - 4 hours




Post new topic Reply to topic  [ 28 posts ]  Go to page 1, 2  Next
Author Message
 Post subject: Seperating Saltwater and Freshwater Pearls
PostPosted: Tue May 08, 2012 4:20 am 
Offline
Site Admin
User avatar

Joined: Sun Oct 16, 2005 12:22 pm
Posts: 19632
Location: San Francisco
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.


Top
 Profile  
Reply with quote  
 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Tue May 08, 2012 5:50 am 
Offline
Valued Contributor
User avatar

Joined: Sat Oct 13, 2007 9:03 am
Posts: 109
Location: Italy
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%?

Bye
Paolino

_________________
Paolo Cerruti G.G. (GIA)

"When the winds of change blow,
some people build walls and others build windmills"

www.paolocerruti.it


Top
 Profile  
Reply with quote  
 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Tue May 08, 2012 6:03 am 
Offline
Valued Contributor
User avatar

Joined: Sat Oct 13, 2007 9:03 am
Posts: 109
Location: Italy
This strips detect a range of ppm...

from 0.02 to 2 ppm

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

_________________
Paolo Cerruti G.G. (GIA)

"When the winds of change blow,
some people build walls and others build windmills"

www.paolocerruti.it


Top
 Profile  
Reply with quote  
 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Tue May 08, 2012 11:16 am 
Offline
Site Admin
User avatar

Joined: Sun Oct 16, 2005 12:22 pm
Posts: 19632
Location: San Francisco
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".


Top
 Profile  
Reply with quote  
 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Wed May 09, 2012 3:35 pm 
Offline
Valued Contributor

Joined: Tue Oct 17, 2006 11:33 am
Posts: 402
Location: New Zealand
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.

_________________
Gemstein.com


Top
 Profile  
Reply with quote  
 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Wed May 09, 2012 4:02 pm 
Offline
Gold Member

Joined: Sun Jun 28, 2009 9:56 am
Posts: 1215
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.


Top
 Profile  
Reply with quote  
 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Wed May 09, 2012 4:12 pm 
Offline
Valued Contributor

Joined: Tue Oct 17, 2006 11:33 am
Posts: 402
Location: New Zealand
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.

_________________
Gemstein.com


Top
 Profile  
Reply with quote  
 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


Top
  
Reply with quote  
 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Thu May 10, 2012 9:39 am 
Offline
Gemology Online Veteran
User avatar

Joined: Wed Dec 30, 2009 11:44 am
Posts: 519
Location: PAKISTAN-Peshawar
Thanks Barbra Voltaire, it's really very informative post.

with best regards

HUK

_________________
Gemology for everyone.
HUK


Top
 Profile  
Reply with quote  
 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Thu May 10, 2012 10:00 am 
Offline
Site Admin
User avatar

Joined: Sun Oct 16, 2005 12:22 pm
Posts: 19632
Location: San Francisco
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.


Top
 Profile  
Reply with quote  
 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Thu May 10, 2012 11:11 am 
Offline
Gemology Online Royal Princess

Joined: Mon Oct 17, 2005 10:56 am
Posts: 6462
Location: The frozen north prairie :-/
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) .

_________________
IIJA Registered Gemologist
GIA Graduate Gemologist


Top
 Profile  
Reply with quote  
 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Thu Aug 02, 2012 7:06 pm 
Offline
Valued Contributor

Joined: Mon Oct 17, 2005 11:10 am
Posts: 287
Location: Illinois
Just curious. Did anything come of these tests?

_________________
I love the smell of Methylene Iodide in the morning...


Top
 Profile  
Reply with quote  
 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Thu Aug 02, 2012 8:05 pm 
Offline
Gemology Online Royal Princess

Joined: Mon Oct 17, 2005 10:56 am
Posts: 6462
Location: The frozen north prairie :-/
I never heard anything ... and I still have the "crap" pearl that could be sacrificed :twisted: .

_________________
IIJA Registered Gemologist
GIA Graduate Gemologist


Top
 Profile  
Reply with quote  
 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Thu Aug 02, 2012 10:32 pm 
Offline
Site Admin
User avatar

Joined: Sun Oct 16, 2005 12:22 pm
Posts: 19632
Location: San Francisco
I wonder if earthling got around to further testing....hope he sees this.


Top
 Profile  
Reply with quote  
 Post subject: Re: Seperating Saltwater and Freshwater Pearls
PostPosted: Fri Aug 03, 2012 3:17 am 
Offline
Site Admin
User avatar

Joined: Fri May 12, 2006 11:24 am
Posts: 7497
Location: Rome, Italy
i purchased the strip kit but still didn't had the time for test....... :( :( :(

_________________
GemmoRaman-532 - GemmoFTIR - GemmoSphere - EXA


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 28 posts ]  Go to page 1, 2  Next

All times are UTC - 4 hours


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
Gemology Style ported to phpBB3 by Christian Bullock