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Hermannroseite - Tsumeb Mine, Tsumeb, Otjikoto Region, Namibia

Posted by Jochen Schlüter  
Hermannroseite - Tsumeb Mine, Tsumeb, Otjikoto Region, Namibia
June 26, 2012 09:06AM
Hermannroseite:
I don't think that those two pictures actually show hermannroseite, but copper phosphates (reichenbachite, pseudomalachite) which are associated with hermannroseite.

The holotype of hermannroseite is still complete, so that sample can not be part of the holotype.
Re: Hermannroseite - Tsumeb Mine, Tsumeb, Otjikoto Region, Namibia
June 26, 2012 10:09AM
at    
Message sent.
Re: Hermannroseite - Tsumeb Mine, Tsumeb, Otjikoto Region, Namibia
June 26, 2012 10:09AM
gr    
Dear Dr. Schlüter,

From the wording used by the uploader ("his piece seems to be a former part of the holotype, as the accompanying label does mention it to be from a find of Bruno Geier in 1964, and once being part of the collection G. Gebhard.") I believe it is meant that the pictured specimen was part of the same specimen from which the holotype of Hermannroseite came from, but before it became a holotype for the new species.

Of course, I can not further comment on the validity of such claim, or on the actual identity of the pictured specimen.

Lefteris.
Hi!

Analytical check is planned. I did an update on the text of both photos for clarification.

My remarks on the relation to the (now) holotype is exactly as Lefteris wrote. The sample has a genuine Gebhard label with the notice of "Bruno Geier 1964". In the publication of hermannroseite it is stated that only one piece does exist. So it is most likely from this find, be it really only one single piece or a piece with some crumbs, that – as it seems - were passed on to other collector(s) some time ago.

Best regards,
Franz
Do we now start creating minerals by chosing specimens of mineral assemblages similar to the reference, i.e. type, specimen hoping that the new mineral would be present as well?

I wish that we can finish this kind of irritation. Here are my remarks:

1. There cannot be a part of the holotype somewhere and even with a Gebhard label since the holotype specimen was never touched before examination
2. Somewhere might be a Gebhard label of a specimen owned by Bruno Geier 1964, but not related to hermannroseite. Bruno Geier had some specimens which we identified as reichenbachite, but this had a totally different paragenesis with mangenese oxides.


It would help us all if the irritating photo and description would be cancelled. Just wait for the official publication on hermannroseite to see that there is even no similarity between the holotype and this so-called hermannroseite
Dear Mr. Gebhard!

To check the proportionality of this case: It is not absurd or slanderous to judge a sample after close similarities and congruities within the given frame (dates, origin, label, general and detailed appearance backed by at least some experience in the case of localities or groups of minerals).

Such activities (and to a lesser extent even analyses which turn ut to be flawed by any reasons) can lead to wrong assumptions, yes. Mistakes can be corrected and explained, so something is to be learned. An analytical check was planned anyway and it will lead to a definite result. My mistake was to put it up premature (sorry for that!), but I cannot see any real harm done.

But even in this discussion your comments and those of Dr. Schlüter are slightly contradicting. He wrote: “I don't think that those two pictures actually show hermannroseite, but copper phosphates (reichenbachite, pseudomalachite) which are associated with hermannroseite.”; … while you are totally excluding that on this reichenbachite-bearing (or pseudomalachite, ludjibaite?) sample there could be any hermannroseite.

Furthermore you write about a “totally different paragenesis” of this “reichenbachite” with “manganese oxides”. Manganese oxides/hydroxides are a vital part in the holotype sample of hermannroseite, as is pseudomalachite associated in the holotype. I can’t see those being “totally different” based on the information at present.

Can you exclude that Bruno Geier had those pieces NOT from totally different sources inside the mine? But that is what you’re implying. It is quite an unambiguous strong formulation to say “that there is even no similarity …”; as any find of such phosphates (single or in association) from Tsumeb is very special and therefore confocal.

Did you find reichenbachite only on those “totally different” samples? I bet there are more phases (phosphates / arsenates), as colour and lustre variations are clearly visible with low to mid power magnification.

BTW I did read the work on hermannroseite. Where will be explanations regarding this context-free "reichenbachite" in the official publication on hermannroseite?

No reference of (separate) reichenbachite can be found in this work by Jochen Schlüter, Dieter Pohl, and Georg Gebhard "The new mineral hermannroseite, CaCu(PO4,AsO4)(OH), the phosphate analogue of conichalcite, from Tsumeb, Namibia".

In N. Jb. Miner. Abh. 188/2, 135–140 (Published online January 2011) one can find statements like:

"Only one sample is known so far (Figure 1), it was provided from one of the authors (GG), who received it from Bruno Geiers heirs." How can you know for sure that "There cannot be a part of the holotype somewhere and even with a Gebhard label since the holotype specimen was never touched before examination." if you got the sample after the death of Mr. Geier in 1987 after he found it in the 60s?

On "Occurrence and general appearance" we read: "The holotype sample shows green glassy botryoidal aggregates lining a vug in masses of hydroxylapatite (Fig. 1) coloured black by amorphous manganese oxides/hydroxides which occasionally include pseudomalachite as well."

A side note: With the information available I did nothing spectacular wrong. It is clear to me to change and cancel asap as informations and corrections by Dr. Schlüter and you arise, for which I am thankful. Nevertheless the tone you are using is a little bit inappropriate imho, especially as a first contact.

Best regards,
Franz
Re: Hermannroseite - Tsumeb Mine, Tsumeb, Otjikoto Region, Namibia
July 04, 2012 06:53PM
Franz;

If I was contradicted by Mr. Gebhard on a Tsumeb mineral, I would say thank you for taking the time to clear this up, and correct the page immediately, instead of whining about his tone, and debating the issue.

But maybe that's just me. I have a thick skin, and am humble in the face of confirmed authorities with massive experience.
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