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
19 Aug-20:11:06 Re: ferberite, pyrite, siderite, and..... ? (Justin Hickok)
19 Aug-17:07:41 Re: collection of heimo hellwig (Franjungle)
19 Aug-16:31:42 Re: question about fluorite on quartz (Protium)
19 Aug-16:11:36 Re: collection of fiebre verde - coscuez (#708) (Fiebre Verde)
19 Aug-14:07:39 Re: crystal cavity + green vein poss. Chlorite? (Kara)
19 Aug-13:27:25 Re: crystal cavity + green vein poss. Chlorite? (Peter Megaw)
19 Aug-13:03:34 Re: crystal cavity + green vein poss. Chlorite? (Peter Lemkin)
19 Aug-12:45:44 Re: question about fluorite on quartz (Peter Megaw)
19 Aug-09:49:30 Re: question about fluorite on quartz (Protium)
19 Aug-09:35:37 Re: question about fluorite on quartz (Peter Megaw)
19 Aug-08:54:35 Re: question about fluorite on quartz (Protium)
19 Aug-08:48:14 Re: crystal cavity + green vein poss. Chlorite? (Peter Megaw)
19 Aug-08:37:38 Re: mineral id help. (Matt_zukowski)
19 Aug-08:34:17 Re: ferberite, pyrite, siderite, and..... ? (Mathias)
19 Aug-08:29:08 Crystal cavity + green vein poss. Chlorite? (Kara)
19 Aug-07:43:35 Re: ferberite, pyrite, siderite, and..... ? (Jordi Fabre)
19 Aug-07:28:02 Re: mineral id help. (Jordi Fabre)
19 Aug-05:20:23 Re: mineral id help. (John S. White)
19 Aug-05:12:35 Re: abrasives repairing polishing crystals (Diamond)
19 Aug-04:02:54 Re: abrasives repairing polishing crystals (Duncan Miller)
19 Aug-03:36:59 Re: collection of philippe durand (Philippe Durand)
19 Aug-03:13:14 Ferberite, pyrite, siderite, and..... ? (Mathias)
18 Aug-20:28:11 Re: mineral id help. (Robson Vieira)
18 Aug-20:23:32 Re: mineral id help. (Robson Vieira)
18 Aug-20:03:09 Question about fluorite on quartz (Protium)

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
44971


The time now is Aug 19, 2018 20:22

Search for a textSearch for a text   

A general guide for using the Forum with some rules and tips
Smithsonite from Adis Abeba, Ethiopia??
  
  Index -> What is it? - Where is it from?
Like
3


View previous topic :: View next topic  
Author Message

herrej




Joined: 15 Jul 2013
Posts: 52
Location: Rotterdam

View user's profile

Send private message

PostPosted: May 05, 2018 13:03    Post subject: Smithsonite from Adis Abeba, Ethiopia??  

This is a nice piece I think but I'm not sure what it is and what is it origin.
It was sold to me as Smithsonite from Adis Abeba, Ethiopia a long time ago.
This seems not correct to me. Can't find anything in books, literature or the internet about Smithsonite at Adis Abeba.
Anyone an idea of the mineral and the origin? The matrix is basalt like.



P3170494.jpg
 Description:
 Viewed:  1505 Time(s)

P3170494.jpg


Back to top
Reply to topic Reply with quote
Like
   

Kevin Schofield




Joined: 05 Jan 2018
Posts: 53
Location: Houston TX

View user's profile

Send private message

PostPosted: May 05, 2018 14:45    Post subject: Re: Smithsonite from Adis Abeba, Ethiopia??  

herrej wrote:
This is a nice piece I think but I'm not sure what it is and what is it origin.
It was sold to me as Smithsonite from Adis Abeba, Ethiopia a long time ago.
This seems not correct to me. Can't find anything in books, literature or the internet about Smithsonite at Adis Abeba.
Anyone an idea of the mineral and the origin? The matrix is basalt like.


Looks to me suspiciously like "Manufactured, from Somebody's Basement"....

But happy to be demonstrated to be incorrect of course..

_________________
Veni, Vidi, Emi
Back to top
Reply to topic Reply with quote
Like
1
   

Peter Lemkin




Joined: 18 Nov 2016
Posts: 137
Location: Prague

View user's profile

Send private message

PostPosted: May 05, 2018 22:22    Post subject: Re: Smithsonite from Adis Abeba, Ethiopia??  

That was my thought too. The 'matrix' looks false [unnatural] and the crystals seem unnaturally attached and of almost exactly the same size and form.......I think you might consider and explore if this is real or not.....sorry to say..... I also have never heard of this mineral from this location....
Back to top
Reply to topic Reply with quote
Like
   

Jim Robison




Joined: 17 Nov 2010
Posts: 55

View user's profile

Send private message

PostPosted: May 05, 2018 23:19    Post subject: Re: Smithsonite from Adis Abeba, Ethiopia??  

Are you sure this is smithsonite? There is some from Morocco that has this appearance but the crystal size is much smaller in appearance. There is no size given on the piece, but those I have seen from there have fairly small diameter rhomb groups, in the range of 1 cm or so. . Indeed, you can see a shadow underneath the mineral, strongly indicating the white is simply stuck onto the matrix. If the matrix is basalt then calcite would be the potential later mineral, but not in this case. My first reaction was a Romanian calcite, though it would make absolutely no sense to dismantle one of those to construct this rock.
Back to top
Reply to topic Reply with quote
Like
   

nicu




Joined: 01 Sep 2010
Posts: 82
Location: Bucharest


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: May 06, 2018 00:19    Post subject: Re: Smithsonite from Adis Abeba, Ethiopia??  

The matrix is basaltic, possibly sprinkled with small Olivine crystals. The two dome-like formations seem to be a carbonate mineral but certainly, it is not Smithsonite.
They are man-made attached on the basis. I don't think it would come from Romania....

_________________
Earth's Tears
Back to top
Reply to topic Reply with quote
Like
   

alfredo
Site Admin



Joined: 30 Jan 2008
Posts: 698
Location: New York


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: May 06, 2018 02:44    Post subject: Re: Smithsonite from Adis Abeba, Ethiopia??  

Another possibility is that the vug was originally lined with a thin layer of saponite, ferrosaponite or other clay-like mineral, which is very common in basalt vugs. Younger minerals like zeolites and calcite grow on top of this clay layer, which is why some basalt vugs get destroyed in ultrasonic cleaners, because the older clay layer desintegrates. It could be the case here, the clay layer partially washed away, leaving that gap between the calcite groups and the matrix. Or it might be glued, like others have said, but not necessarily.

The basalt has an oxidized brownish color, unlike the more normal grey tones. I've collected vuggy brownish basalts like this myself on the highway going West from Addis Abeba, but closer toward Lekemti, although my specimens had heulandite inside rather than calcite, but it could nevertheless easily be from that part of Ethiopia..
Back to top
Reply to topic Reply with quote
Like
   

herrej




Joined: 15 Jul 2013
Posts: 52
Location: Rotterdam

View user's profile

Send private message

PostPosted: May 06, 2018 04:55    Post subject: Re: Smithsonite from Adis Abeba, Ethiopia??  

Thanks you all for the replies. The hemispheres are not glued on the matrix. The lightbreaking/reflections on the photo gives the impressions there is a line between the hemispheres and the matrix but this is an illusion.
The piece is about 3 cm and the cost was $5, so if you want to make a buck with constructing you don't earn a lot. And also unlikely to break a good romanian piece to construct this one.
The matrix is like the Calcite hemispheres you see sometimes from Italian Calcite on basalt, also sometimes brownish.
I think Alfredo's post is the most likely location of the piece and that is is Calcite.
Back to top
Reply to topic Reply with quote
Like
1
   

Gagat Minerals




Joined: 08 Nov 2017
Posts: 29
Location: Greater London


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: May 06, 2018 07:08    Post subject: Re: Smithsonite from Adis Abeba, Ethiopia??  

Peter Lemkin wrote:
The 'matrix' looks false [unnatural] .......


nicu wrote:
The matrix is basaltic, possibly sprinkled with small Olivine crystals. The two dome-like formations seem to be a carbonate mineral....


alfredo wrote:
... the vug was originally lined with a thin layer of saponite, ferrosaponite or other clay-like mineral, which is very common in basalt vugs. Younger minerals like zeolites and calcite grow on top of this clay layer..


in Poland in very similar basalt vugs of Lower Silesia, this other dark minerals coming out of smectite layers are mostly ilmenites - and calcite like this is quite common.
Back to top
Reply to topic Reply with quote
Like
1
   
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