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Pierre Joubert
Joined: 09 Mar 2012
Posts: 1605
Location: Western Cape
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 Posted: Mar 04, 2013 11:25 Post subject: Joubertite????? |
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About 10 years ago, I spent about one-and-a-half months in Uis, a small mining town in Namibia, approximately 80 km from the Brandberg. If you Google that area, you will see enormous mine dumps and quarries, where, not too long ago, they mined tin on a large scale. I spent a good amount of hours looking for anything interesting at that mine and came across this unusual mineral that forms a thin coating on rock (feldspar and quartz). I was only able to find a few small pieces. I have never seen anything like this before, but for all I know, you can probably collect tons of the stuff in Mexico. Can someone tell me what it is? It can be scratched with a knife, and probably is as hard as calcite.
| Description: |
unknown mineral
Uis, Tin mine, Namibia
14 x 09 mm (yellow mineral) |
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9068 Time(s) |
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| Description: |
unknown mineral
Uis, Tin mine, Namibia
14 x 09 mm (yellow mineral)
Same as above |
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9071 Time(s) |
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| Description: |
unknown mineral
Uis, Tin mine, Namibia
14 x 09 mm (yellow mineral)
Same as above. |
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9060 Time(s) |
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| Description: |
unknown mineral
Uis, Tin mine, Namibia
14 x 09 mm (yellow mineral)
unknown mineral |
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| Viewed: |
9057 Time(s) |
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Pierre Joubert
'The tree of silence bears the fruit of peace. ' |
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Josele
Joined: 10 Apr 2012
Posts: 407
Location: Tarifa, Spain
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| Posted: Mar 04, 2013 11:59 Post subject: Re: Joubertite????? |
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| Pierre Joubert wrote: | | ... and probably is as hard as calcite. |
Hi Pierre,
Did you check efervescence with HCl?
Orangish color seems to be only superficial, could be any iron oxide.
And forgive me if I'm confused...
Salut.
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Josele |
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Pierre Joubert
Joined: 09 Mar 2012
Posts: 1605
Location: Western Cape
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| Posted: Mar 04, 2013 13:24 Post subject: Re: Joubertite????? |
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| Josele wrote: | | Pierre Joubert wrote: | | ... and probably is as hard as calcite. |
Hi Pierre,
Did you check efervescence with HCl?
Orangish color seems to be only superficial, could be any iron oxide.
And forgive me if I'm confused...
Salut. |
Hi Josele. I will do that first thing in the morning. The yellow colour has a pearly abalone colouring, or to be more descriptive, sparkling rainbow colours when moved around.
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Pierre Joubert
'The tree of silence bears the fruit of peace. ' |
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GneissWare
Joined: 07 Mar 2008
Posts: 1287
Location: California
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| Posted: Mar 04, 2013 13:34 Post subject: Re: Joubertite????? |
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| Pierre Joubert wrote: |
...The yellow colour has a pearly abalone colouring, or to be more descriptive, sparkling rainbow colours when moved around. |
Many thin Fe coatings display this phenomena.
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Pierre Joubert
Joined: 09 Mar 2012
Posts: 1605
Location: Western Cape
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| Posted: Mar 05, 2013 04:08 Post subject: Re: Joubertite????? |
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Hi Josele, I did do a HC test; no, it does not fizz.
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Pierre Joubert
'The tree of silence bears the fruit of peace. ' |
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John S. White
Site Admin
Joined: 04 Sep 2006
Posts: 1295
Location: Stewartstown, Pennsylvania, USA
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| Posted: Mar 05, 2013 06:22 Post subject: Re: Joubertite????? |
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A thin film of iron oxide or even opal can cause an iridescence such as you describe. I think that GneissWare nailed it.
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John S. White
aka Rondinaire |
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Pierre Joubert
Joined: 09 Mar 2012
Posts: 1605
Location: Western Cape
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| Posted: Mar 05, 2013 08:09 Post subject: Re: Joubertite????? |
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| John S. White wrote: | | A thin film of iron oxide or even opal can cause an iridescence such as you describe. I think that GneissWare nailed it. |
Hi John. Thank you for your contribution. Josele also mentioned iron oxide, and indeed it looks to be the source of the stunning colour. I have added two more photos, noting facets; colouration about 1mm deep, and an unknown clear mineral on top of the yellow. It appears that a mineral (about 1mm thick), with minute facets, formed on the matrix and was coloured by iron oxide.
| Description: |
unknown mineral
Uis, Tin mine, Namibia
FOV approx. 1 cm
Note the clear,small crystals, arrow above, and the coloured layer, below. |
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8871 Time(s) |
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| Description: |
unknown mineral
Uis, Tin mine, Namibia
FOV approx. 1 cm
Note the facets (arrow top); and again the coloured layer, below. |
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| Viewed: |
8879 Time(s) |
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_________________
Pierre Joubert
'The tree of silence bears the fruit of peace. ' |
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