FMF - Friends of Minerals Forum, discussion and message board

[John Williams]

Hi there
I recently collected material from the dumps of this mine and have a specimen with a large vugh lined with nice pale-blue Baryte but mostly covered with a black(managanese oxide?) coating.
Can anyone tell me how this can be removed?
Regards
John

[Jordi Fabre]

Bad news John, I'm afraid that the manganese oxides are too hard to be cleaned without damage for the Baryte.
As you can read Spanish language, please visit this topic of the Spanish forum to get more details:
https://www.foro-minerales.com/forum/viewtopic.php?t=967

Jordi

[John Williams]

Thanks Jordi.
That's a shame since it would make a nice specimen. Is there not any acid that will take the oxide off, for example oxalic acid? I have used oxalic acid on iron oxides with success.
Best regards and Happy Xmas
John

[John Williams]

Hi Jordi
I've just been reading about the Waller Method for cleaning minerals on the internet. It says can be used for removal of iron and manganese oxides from silicate,carbonate and phosphate minerals. It doesn't mention sulphates and, of course, Baryte is barium sulphate, but it might be worth a try. Other collectors may not be aware of this method but it is fully explained on the internet under the headind "The Waller Method".
Regards
John

[Jordi Fabre]

Believe me John, Waller method doesn't work with those manganese oxides.
Anyway, you can try it and then explain to us your experience.

Jordi

[John Williams]

OK Jordi
I'll give it a try in the New Year.
Regards
John

[str4hler]

The story seems to continue here...
https://www.mindat.org/forum.php?read,19,120219,120219#msg-120219

[John Williams]

Hi Frank
Yes I happened to look at the mindat site forum and saw the topic "Cleaning Rhodocrosite" in which it was mentioned that a mixture of hydrogen peroxide and acid(hydrochloric or sulphuric) was effective in removing manganese oxides from specimens of rhodocrosite.
John

[str4hler]

I'm just observing John ;-)

[Jordi Fabre]

Hi John,

As you probably saw by the answers of your other post in Mindat, a mixture of hydrogen peroxide and acid(hydrochloric or sulphuric) is a kind of bomb, very dangerous and risky for your health.
Before to try with such dangerous procedures I strongly suggest to you read this post in the Spanish Forum:
https://www.foro-minerales.com/forum/viewtopic.php?t=154

Jordi

[John Williams]

Thanks for that Jordi!
John

[Claus]

John,

Oxalic acid, 'Waller solution', etc. are excellent for removing iron oxides but as others noted they are not necessarily good for manganese oxides.

Note that most (all?) compounds used to remove iron oxides contain chelating agents, which may harm otherwise fairly stable minerals. I have ruined Fluorite and Baryte with oxalic acid and also Baryte with 'Waller solution'.

All the best

Claus

[John Williams]

Thanks for that Claus.
I have decided not to clean the specimen because the manganese oxides[?] are so hard and thick.
I will go out in the New Year and try and find a specimen that doesn't require much cleaning!
Happy Xmas
John