We use cookies to show content based on your preferences. If you continue to browse you accept their use and installation. More information. >

FMF - Friends of Minerals Forum, discussion and message board
The place to share your mineralogical experiences


Spanish message board






Newest topics and users posts
27 Sep-13:04:15 Re: collection of tobi (Tobi)
27 Sep-11:42:49 Re: what's up with minfind? (Lluis)
27 Sep-11:06:21 Re: collection of joseph d'oliveira (Joseph Doliveira)
27 Sep-10:57:45 Re: what's up with minfind? (Jesse Fisher)
27 Sep-10:49:37 Re: what's up with minfind? (Bob Kerr)
27 Sep-10:22:48 Re: collection of firmo espinar (Firmo Espinar)
27 Sep-10:07:48 Re: what's up with minfind? (Peter Lemkin)
27 Sep-09:53:11 Re: what's up with minfind? (Lluis)
27 Sep-09:48:34 Re: collection of michael shaw (Michael Shaw)
27 Sep-09:38:34 Re: collection of tobi (Michael Shaw)
27 Sep-08:58:44 Re: collection of tobi (Tobi)
27 Sep-06:40:18 Re: what's up with minfind? (James Catmur)
27 Sep-03:29:08 Re: collection of tobi (Dany Mabillard)
27 Sep-02:38:15 Re: what's up with minfind? (Gregc12345)
27 Sep-02:04:20 Re: new generation for picture - ploum (Ploum)
26 Sep-13:59:25 Re: a mineralogical trip through italy by sante celiberti (Sante Celiberti)
26 Sep-13:36:46 Re: collection of tobi (Tobi)
26 Sep-10:55:50 Popular minerals - stokesite from valdemanco, madrid, spain (Jordi Fabre)
26 Sep-05:55:45 Re: collection of volkmar stingl (Volkmar Stingl)
26 Sep-00:39:01 Re: new generation for picture - ploum (Ploum)
25 Sep-18:40:06 Re: please help! shiny dark green crystals (Steve Maslansky)
25 Sep-16:25:16 Re: please help! shiny dark green crystals (Alfredo)
25 Sep-15:47:28 Re: please help! shiny dark green crystals (Kevin Schofield)
25 Sep-15:23:57 Re: please help! shiny dark green crystals (Danieljp)
25 Sep-15:21:31 Re: please help! shiny dark green crystals (Danieljp)

For lists of newest topics and postings click here


RSS RSS

View unanswered posts

Why and how to register

Index Index
 FAQFAQ RegisterRegister  Log inLog in
 {Forgotten your password?}Forgotten your password?  

Like
72478


The time now is Sep 27, 2020 16:58

Search for a textSearch for a text   

A general guide for using the Forum with some rules and tips
Isotopic composition of German Silvers
  
  Index -> Minerals and Mineralogy
Like


View previous topic :: View next topic  
Author Message

Brent Lockhart




Joined: 25 Jan 2012
Posts: 28
Location: Larkspur, Colorado

View user's profile

Send private message

PostPosted: Feb 27, 2020 23:55    Post subject: Isotopic composition of German Silvers  

I had a brief conversation with Terry Wallace a few months ago regarding some isotopic constitution work done with German native Silvers, i.e. Himmelsfurst as an example. There probably is some discussion of the question of these specimens being natural versus man made on this forum, but I've not been able to find it. Can anyone point me to any such discussion or any recent publications on this matter? I believe there may be some recent published isotopic work available which would be most helpful.

Cheers

Brent Lockhart

_________________
Member of the Colorado Chapter, Friends of Mineralogy
Back to top
Reply to topic Reply with quote
Like
   

Jordi Fabre
Overall coordinator of the Forum



Joined: 07 Aug 2006
Posts: 4592
Location: Barcelona


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Feb 28, 2020 14:33    Post subject: Re: Isotopic composition of German Silvers  

Brent Lockhart wrote:
...I've not been able to find it. Can anyone point me to any such discussion or any recent publications on this matter?...

Not directly related about the German silvers but yes about some of the Imiter silvers and indirectly also related with the German ones:
Wire "silvers" from Imiter (Morocco)
Back to top
Reply to topic Reply with quote
Like
   

Brent Lockhart




Joined: 25 Jan 2012
Posts: 28
Location: Larkspur, Colorado

View user's profile

Send private message

PostPosted: Feb 28, 2020 15:13    Post subject: Re: Isotopic composition of German Silvers  

Hi Jordi

Thank you for directing me to this discussion, it helps a lot. I am collecting miniatures now, and am trying to think through what species I would include. I used to own a very good Freiburg Silver wire which was about 17 cm, tall, coming out of an important European collection. There was no doubt that this one came out in the 19th century or earlier, and as such was unquestionably natural on its matrix. But now, as in the Moroccan case, there are questions about smaller specimens' authenticity. In this case it is thought that some pieces may be smelter by-products or lab grown. I had not realized that this uncertainty extended to other localities. So I am looking for any good diagnostic tools to verify or debunk these doubts. Thanks again for helping me out.

Cheers

Brent

_________________
Member of the Colorado Chapter, Friends of Mineralogy
Back to top
Reply to topic Reply with quote
Like
   

Philip Simmons




Joined: 24 Feb 2011
Posts: 77
Location: Albuquerque, New Mexico


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Mar 02, 2020 23:02    Post subject: Re: Isotopic composition of German Silvers  

Brent Lockhart wrote:
Hi Jordi

Thank you for directing me to this discussion, it helps a lot. I am collecting miniatures now, and am trying to think through what species I would include. I used to own a very good Freiburg Silver wire which was about 17 cm, tall, coming out of an important European collection. There was no doubt that this one came out in the 19th century or earlier, and as such was unquestionably natural on its matrix. But now, as in the Moroccan case, there are questions about smaller specimens' authenticity. In this case it is thought that some pieces may be smelter by-products or lab grown. I had not realized that this uncertainty extended to other localities. So I am looking for any good diagnostic tools to verify or debunk these doubts. Thanks again for helping me out.

Cheers

Brent


Hi Brent,

John Rakovan has put some serious time into this particular topic. Along with several other authors, he has publish an excellent paper in the July 2019 issue of Geology. It's a bit of a read if you're not familiar with isotope geochemistry, but it explains much. I don't think there are any fool-proof ways to determine if a specimen is lab grown or natural except through silver isotope fractionation. Synthetic (or manufactured) silvers show an enrichment in heavier silver isotopes (109Ag).

Based on my understanding of the article, just because the German silvers are old does not mean they are unquestionably natural. Due to the ionic conductive properties of acanthite, silvers wires can be easily grown where both minerals occur together. You can even grow silver wires on acanthite without removing or changing the acanthite. It's a very interesting topic, and I hope more information will be forthcoming.

I hope this helps clear things up a bit!
Phil
Back to top
Reply to topic Reply with quote
Like
   

Brent Lockhart




Joined: 25 Jan 2012
Posts: 28
Location: Larkspur, Colorado

View user's profile

Send private message

PostPosted: Mar 02, 2020 23:37    Post subject: Re: Isotopic composition of German Silvers  

Hi Phil

Thanks for the reference, much appreciated. I really was interested in what isotopic evidence had come out of the recent studies and will find a copy of this article. It will certainly bring into question the nature of most of these wire specimens. The piece I was referring to was out of the Bally Prior Museum, coming to them around WWI. The single wire specimen measured 17 cms long and was some 2 cms. wide near the base. While we can never say never, the odds of some lost technology capable of producing such wires in that time frame seems unlikely. At least I haven't seen a flood of very large wire silvers entering the market yet.

Thanks for the tip, I'll try to muddle my way through the article and appreciate your time replying to my question.

Cheers

Brent

_________________
Member of the Colorado Chapter, Friends of Mineralogy
Back to top
Reply to topic Reply with quote
Like
   

Philip Simmons




Joined: 24 Feb 2011
Posts: 77
Location: Albuquerque, New Mexico


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Mar 03, 2020 15:32    Post subject: Re: Isotopic composition of German Silvers  

You're welcome!

It is interesting to see new information regarding this long debated topic. I'm not saying the old German silvers are undoubtedly faked, but it might have been possible that there was a similar situation when compared to the zincites from Poland (at least the ones found from the smelter).

Unfortunately, even scientific research has met with strong (and sometimes powerful) discouragement when topics like this are breached. We shall see if more information comes to light regarding silver wire growth. I love these studies for the scientific information we gain, but when dealing with egos and large sums of money things can get swept under the rug, so to speak.
Back to top
Reply to topic Reply with quote
Like
   

Brent Lockhart




Joined: 25 Jan 2012
Posts: 28
Location: Larkspur, Colorado

View user's profile

Send private message

PostPosted: Mar 03, 2020 23:08    Post subject: Re: Isotopic composition of German Silvers  

Yep, the folks who've paid big bucks for Silvers and the dealers who sold them are not gonna like this. As you point out, isotopic quantity measurement is not something every lab can do. A mass spec (or similar) versus an XRD setup cost is not something I have much of a sense for though. There may be some metallurgical labs around able to do it, but I bet it would be expensive. Think I'll be giving wire Silvers a pass.
_________________
Member of the Colorado Chapter, Friends of Mineralogy
Back to top
Reply to topic Reply with quote
Like
   
Display posts from previous:   
   Index -> Minerals and Mineralogy   All times are GMT - 5 Hours
Page 1 of 1
    

 
Jump to:  
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 vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


All pictures, text, design © Forum FMF 2006-2020


Powered by FMF