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

FMF English Forum is moderated by John S. White and Peter Megaw
 

Spanish message board






Newest topics and users posts
12 Dec-14:13:45 The mizunaka collection - fluorite (Am Mizunaka)
12 Dec-13:21:13 Re: the collection of pierre and riana joubert (Pierre Joubert)
12 Dec-12:45:07 Re: the collection of pierre and riana joubert (Philippe Durand)
12 Dec-09:43:21 Re: collection of michael shaw (Crosstimber)
12 Dec-09:00:41 Re: best labeling material for collection numbers on specimens (Peter Lemkin)
12 Dec-08:45:38 Re: collection of heimo hellwig (Heimo Hellwig)
12 Dec-07:31:11 Re: baryte collection of niels brouwer (Niels Brouwer)
12 Dec-07:00:24 Re: best labeling material for collection numbers on specimens (Peter)
12 Dec-06:41:06 Re: best labeling material for collection numbers on specimens (Herman Van Dennebroek)
12 Dec-05:39:42 Re: best labeling material for collection numbers on specimens (Stefan Koch)
12 Dec-05:18:42 Re: best labeling material for collection numbers on specimens (Peter Lemkin)
12 Dec-02:50:42 Re: the collection of pierre and riana joubert (Pierre Joubert)
12 Dec-02:35:40 Re: the collection of pierre and riana joubert (Heimo Hellwig)
12 Dec-02:11:01 Re: the collection of pierre and riana joubert (Pierre Joubert)
12 Dec-02:07:01 Re: best labeling material for collection numbers on specimens (Wendellwilson)
12 Dec-01:45:46 Best labeling material for collection numbers on specimens (Peter Lemkin)
11 Dec-20:05:45 Re: juan, spain. Help. (J. G. Alcolea)
11 Dec-19:40:16 Re: juan, spain. Help. (Montanpark)
11 Dec-18:37:37 Re: juan, spain. Help. (J. G. Alcolea)
11 Dec-18:07:16 Re: juan, spain. Help. (Joseph D'oliveira)
11 Dec-18:04:23 Re: juan, spain. Help. (Montanpark)
11 Dec-17:42:05 Juan, spain. Help. (J. G. Alcolea)
11 Dec-15:16:19 Re: new generation for picture - ploum (Ploum)
10 Dec-19:01:18 Re: don lum collection (Don Lum)
10 Dec-14:51:04 Re: the mizunaka collection (Am Mizunaka)

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
48266


The time now is Dec 12, 2018 14:25

Search for a textSearch for a text   

A general guide for using the Forum with some rules and tips
Tsumeb Gypsum?
  
  Index -> What is it? - Where is it from?
Like
10


View previous topic :: View next topic  
Author Message

Heimo Hellwig




Joined: 03 Aug 2014
Posts: 677
Location: Swakopmund


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Nov 13, 2018 01:17    Post subject: Tsumeb Gypsum?  

Hi everybody! The following 3 Gypsum variety Selenite specimens come out of a pre1972 "Namibia/Tsumeb" collection.
I did some research, but could not find any samples similar to these specimens. Any advice and/or guidance to possibly to where they are from will be appreciated.
Thank you.



DSCF2516.JPG
 Mineral: Gypsum variety Selenite
 Locality:
Namibia
 Dimensions: 19mm x 15mm x 48mm
 Description:
 Viewed:  737 Time(s)

DSCF2516.JPG



DSCF2518.JPG
 Mineral: Gypsum variety Selenite
 Locality:
Namibia
 Dimensions: 19mm x 15mm x 32mm
 Description:
 Viewed:  736 Time(s)

DSCF2518.JPG



DSCF2520.JPG
 Mineral: Gypsum variety Selenite
 Locality:
Namibia
 Dimensions: 23mm x 61mm x 11mm
 Description:
 Viewed:  737 Time(s)

DSCF2520.JPG


Back to top
Reply to topic Reply with quote
Like
3
   

alfredo
Site Admin



Joined: 30 Jan 2008
Posts: 712


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Nov 13, 2018 04:37    Post subject: Re: Tsumeb Gypsum?  

Gypsum in various habits is remarkably common in any mine where there are decomposing sulphides along with some calcite, aragonite or dolomite for it to react with. Mindat and Mineralienatlas have a few photos of such specimens, and of course they could look quite different in other veins or pockets: https://www.mindat.org/gallery.php?loc=2428&min=1784
https://www.mineralienatlas.de/lexikon/index.php/LokationMineralData?param=3290,1386,1
Back to top
Reply to topic Reply with quote
Like
3
   

James
Site Admin



Joined: 14 Sep 2006
Posts: 619
Location: Cambridge


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Nov 13, 2018 04:58    Post subject: Re: Tsumeb Gypsum?  

You could also visit all the photos of Gypsum from the FMF

https://www.topminerals.info/index.php?searchterms=gypsum&searchauthor=-&level=search
Back to top
Reply to topic Reply with quote
Like
1
   

Heimo Hellwig




Joined: 03 Aug 2014
Posts: 677
Location: Swakopmund


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Nov 13, 2018 07:08    Post subject: Re: Tsumeb Gypsum?  

Thank you very much for the information Alfredo and James - appreciated.
Kind regards.
Back to top
Reply to topic Reply with quote
Like
   

John Betts




Joined: 07 Jun 2012
Posts: 117
Location: New York City

View user's profile

Send private message

PostPosted: Nov 13, 2018 07:50    Post subject: Re: Tsumeb Gypsum?  

What type of "research" did you perform?
The reference book Tsumeb II lists gypsum as common.

It also states many specimens identified as gypsum are actually misidentified and could be actually schultenite, leiteite or chubobaite.

_________________
John Betts
Back to top
Reply to topic Reply with quote
Like
1
   

Heimo Hellwig




Joined: 03 Aug 2014
Posts: 677
Location: Swakopmund


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Nov 13, 2018 08:17    Post subject: Re: Tsumeb Gypsum?  

John Betts wrote:
What type of "research" did you perform?
The reference book Tsumeb II lists gypsum as common.

It also states many specimens identified as gypsum are actually misidentified and could be actually schultenite, leiteite or chubobaite.


Hello John, I have the three Bode (Ludi von Bezing) published books as well as the book by Georg Gebhard. Through these I came to the Gypsum var. Selenite conclusion. I also came up with Schultenite and Leiteite, but Chubobaite is new to me. Not being an expert and the lack of lab testing facilities in Namibia makes it difficult to reach some degree of certainty.
Kind regards.
Back to top
Reply to topic Reply with quote
Like
   

lluis




Joined: 17 Nov 2006
Posts: 614

View user's profile

Send private message

PostPosted: Nov 13, 2018 15:37    Post subject: Re: Tsumeb Gypsum?  

Hi, Heimo

I think also that specimen is gypsum
Leitetite appears in lamellae, no crystals (wish I have such a leitetite!)
The other two minerals crystallize also different from your habit.
And are arsenates...
That are easy to detect....

With best wishes

Lluís
Back to top
Reply to topic Reply with quote
Like
1
   

Heimo Hellwig




Joined: 03 Aug 2014
Posts: 677
Location: Swakopmund


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Nov 14, 2018 01:47    Post subject: Re: Tsumeb Gypsum?  

lluis wrote:
Hi, Heimo

I think also that specimen is gypsum
Leitetite appears in lamellae, no crystals (wish I have such a leitetite!)
The other two minerals crystallize also different from your habit.
And are arsenates...
That are easy to detect....

With best wishes

Lluís


Hello Lluis,

Thank you very much for the additional information. Having looked at the sites suggested by Alfredo and James, I am now pretty sure that the specimens are gypsum. The only question that remains is where do they come from, although I think that this will remain uncertain.

Kind regards,
Heimo
Back to top
Reply to topic Reply with quote
Like
   

alfredo
Site Admin



Joined: 30 Jan 2008
Posts: 712


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Nov 14, 2018 09:51    Post subject: Re: Tsumeb Gypsum?  

Heimo, Why do you doubt the original attribution to Tsumeb? Usually I accept locality attributions as given, UNLESS there is some reason to doubt it (for example, the crystals have the wrong type of matrix or paragenesis for the locality, or look too much like material from another locality, or the collector/dealer who provided them was notorious for screwing up locality information). In this case I don't see any particular reason to doubt it, unless you are aware of something the rest of us don't know yet. Was there other material in the same collection attributed to Tsumeb that was obviously not from there?
Back to top
Reply to topic Reply with quote
Like
1
   

Heimo Hellwig




Joined: 03 Aug 2014
Posts: 677
Location: Swakopmund


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Nov 14, 2018 11:06    Post subject: Re: Tsumeb Gypsum?  

alfredo wrote:
Heimo, Why do you doubt the original attribution to Tsumeb? Usually I accept locality attributions as given, UNLESS there is some reason to doubt it (for example, the crystals have the wrong type of matrix or paragenesis for the locality, or look too much like material from another locality, or the collector/dealer who provided them was notorious for screwing up locality information). In this case I don't see any particular reason to doubt it, unless you are aware of something the rest of us don't know yet. Was there other material in the same collection attributed to Tsumeb that was obviously not from there?


Hi Alfredo, you are absolutely right. Apart from a few Schorl and Quartz pieces the remainder is certainly Tsumeb. I just have not seen anything similar from Tsumeb since my involvement with Tsumeb minarals 8 years ago. Sometimes it seems that Tsumeb normally poses more questions than answers. Kind regards.
Back to top
Reply to topic Reply with quote
Like
   

Debbie Woolf




Joined: 09 Feb 2009
Posts: 165
Location: Kent


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Nov 14, 2018 18:42    Post subject: Re: Tsumeb Gypsum?  

Have you considered Rosh Pinah mine?
Back to top
Reply to topic Reply with quote
Like
   

Heimo Hellwig




Joined: 03 Aug 2014
Posts: 677
Location: Swakopmund


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Nov 15, 2018 00:12    Post subject: Re: Tsumeb Gypsum?  

Debbie Woolf wrote:
Have you considered Rosh Pinah mine?


Hi Debbie. I have, with Tsumeb remaining to be the greater probability.
Back to top
Reply to topic Reply with quote
Like
   
Display posts from previous:   
   Index -> What is it? - Where is it from?   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 2006-2018


Powered by FMF