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Mathias
Joined: 01 Apr 2018
Posts: 146
Location: Vlodrop
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Posted: Mar 08, 2020 12:39 Post subject: Goethite |
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Dear Friends of Minerals,
A few months ago, I purchased a specimen with the following Label:
Goethite, Herdorf, Germany.
The specimen is heavy (4 kilo), 18 x 12 cm.
I can't find a similar specimen on Mindat.
The specimen has a layered structure and layers are approximately 1 cm thick.
Has anybody ever encountered a similar specimen before?
How does this structure form?
Thanks,
Mathias
Mineral: | Goethite |
Dimensions: | 18 cm x 12 (cm) |
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Tobi
Site Admin
Joined: 07 Apr 2009
Posts: 4110
Location: Germany
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Posted: Mar 09, 2020 06:12 Post subject: Re: Goethite |
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Hi Mathias,
Herdorf is not one single locality but a mining area with several mines, the most famous is for sure Wolf Mine where the legendary rhodochrosites come from. I don't know for sure if this specimen is from that area but iron minerals like goethite or limonite are common there in different shapes so maybe the information is correct, not sure.
Regards
Tobi
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Matt_Zukowski
Site Admin
Joined: 10 Apr 2009
Posts: 707
Location: Alaska
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Posted: Mar 09, 2020 17:12 Post subject: Re: Goethite |
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It looks like petrified wood. Any possibility it is wood replaced in part by Fe/Mn oxides/hydroxides?
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Roger Warin
Joined: 23 Jan 2013
Posts: 1177
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Posted: Mar 09, 2020 17:31 Post subject: Re: Goethite |
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The needle crystals are vertically associated and form layers of successive deposits.
In addition, the wood does not contain horizontal interruptions.
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