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Improving Mindat.orgschaurteite?

13th Nov 2006 03:18 UTCBrent Thorne Expert

The recent mindat photo of schaurteite http://www.mindat.org/photo-79350.html looks very similar to a mineral that I had analyzed and it turned out to be aragonite. The aragonite is found with tscumcorite, jamesite, calcite and duftite. The mineral in question looks to be associated with duftite. Schuarteite is usually only found with germanite and calcite.

13th Nov 2006 04:32 UTCJason B. Smith Expert

Both of the specimens you are questioning came from the Marcelle Weber collection. The 'fleischerite' was given to marcelle by Neal Yedlin. The 'schaurteite' was traded to her from Lou Perloff. I am not aware where the specimens came from before that. I will leave the photos up for the time being so that others can look at them and comment. I would question the schaurteite over the fleischerite. If you wish Brent I will send the specimens to you so that you can have a closer look. You seem to have a good handle on tsumeb.

13th Nov 2006 04:39 UTCJason B. Smith Expert

I just put a small clot of the 'fleischerite' fibers in a drop of dilute HCL and there is no fizzing. There are also cerussites on the specimen. Anyone willing to analyze a small bit of this for me?? I would be greatful. I would think that Neal Yedlin wouldn't knowingly give erroneous material away.

I am not so sure about the shaurteite specimen. I also have a jamesite with a very similar matrix that also came from marcelles collection, maybe from the same piece of rock, both from Lou Perloff. There are very few xls on the specimen but I will try and acid test them tomorrow.

Thanks, Jason.

13th Nov 2006 16:37 UTCBrent Thorne Expert

Hello Jason,

I am not a authority on Tsumeb rare species, but I do have a extensive Tsumeb collection. I know that a lot of dundasite was sold as "fleischerite". I have a specimen of azurite with dundasite and the material looks similar to the "fleischerite" that you have in the photo. As I mentioned, the "schaurteite" photo is similar to material that I have had analyzed and it turned out to be aragonite. Needless to say, these specimens are almost impossible to sight identify. I am questioning the photos because the minerals that they are associated with do not match the original descriptions of the type specimens. I think the only way to verify the specimens is to have them analyzed by EDAX for germanium in the composition.

Brent Thorne

13th Nov 2006 17:27 UTCJason B. Smith Expert

Hi Brent.

Thanks for the comments. I do not in any way want to post erroneous photos. I think we all feel this way. I have a small tsumeb suite but I gave up on it rather early on due to the outrageous prices for some of those rarities. I purchased these in a lot from Marcelles collection at a very good price. We all know how unreliable labels are, especially on older specimens.

I am still going to leave the photos up temporarily in order for other folks to have a look at them and leave their comments. I will also try my best to at least have the "fleischerite" tested. There is enough on it that I can sacrifice a bit.

Thanks again for your kind and helpful comments and I apologize to anyone ahead of time that I may mislead with the photos until I get it straightened out. Thanks, Jason.

22nd Nov 2006 23:20 UTCBrent Thorne Expert

Hello Jason,

It looks as if no on is willing to comment on the photographs or does not have enough knowledge about Tsumeb rare species to make a comment. As I mentioned, I am not an expert on Tsumeb rarities but I do have both species in my collection. The fleischerite came from the type specimen that resides in the Smithsonian. I have three schaurteite specimens that have all been analyzed by SEM EDAX. I have asked Dr. Terry Seward, whom sewardite is named for and someone I consider a Tsumeb species expert, to take a look at the two photographs in question. He says; "I've just been looking at the two photos posted by JSB of Fleischerite(with

azurite) and Schaurteite (with duftite?). I agree with you - both are

probably incorrectly identified. The Fleischerite is probably Dundasite (or

related dundasite-like phase) - there was some of this material (i.e.

dundasite + azurite) found in the 1970's and most of it was sold

incorrectly as "fleischerite" . - I have some of this material (X-ray'd)

and am thus familiar with it. Actually, if JBS takes a look at page 202 of the first (German) edition of

Gebhard's "TSUMEB" book, he will see a photo of Dundasite with Azurite very

similar to the one he posted on Mindat. There is also a brief comment (in

German) mentioning that most of this material was sold as "Fleischerite" in

the mid-1970's. This is also stated on p.284 (but no photo) of the English

edition of his "TSUMEB" book. Fleischerite is a very rare mineral at Tsumeb

and there may be only 3 or 4 authentic specimens known. I do not have a

specimen myself although I've purchased many samples labelled

"Fleischerite" over the years - all were incorrectly identified.

Schaurteite is a little more frequently encountered but is still very rare.

The white needles with duftite(?) are

probably aragonite - the association is remaniscent of one of the jamesite

associations (remember!) and JSB should check his specimen for jamesite. Just because the specimens came from Yedlin and Perloff, doesn't mean that

they are correctly identified. Both were exceptionally skilled observers

and carefull with their id's but we have all been caught out from time to

time by well-intentioned but incorrect identifcations from others - and

Tsumeb material is a minefield of such problems. "

Since someone from Mindat has decided to use your photos to portray the two species on the species description page, I think it is important that these two photographs should be questioned as to the validity of the identification.

Brent Thorne

23rd Nov 2006 06:25 UTCRobert Meyer Manager

Hello,

The photograph and its association looks similar to calcium carbonate, presumably aragonite, that I had analyzed from an assemblage (paragenesis) of species that includes Duftite, Zn-Dolomite, Tsumcorite, Jamesite, Copper, Cuprite, Goethite, and Mottramite.

One thing, the aragonite sprays on my specimens from this "jamesite-tsumcorite" assemblage are slightly less silky and somewhat more transparent than the photo image, but this is the type of thing that is difficult to depict or ascertain in a photograph.

I have not seen or heard of Schaurteite not associated with Germanite. All of my specimens occur directly on Germanite/Renierite ore. All of the pieces I have seen have a very silky luster and are white.

My suggestion is to send a needle or two over to Bart Cannon of Cannon Microprobe for an elemental (EDS) analysis. He will charge a modest fee for this service, but an authentic schaurteite is worth some hundreds of dollars, so it is a justifiable expense. Be sure to ask him about his deal for 10 grains and take care of some of those other nagging doubts at the same time. An EDS spectra that contained Ca, Ge, and S would be good, but don't be suprised if it only comes up with Ca.

Cheers,

Bob

23rd Nov 2006 09:53 UTCUwe Kolitsch Manager

Schaurteite photo changed to aragonite and comment added.

23rd Nov 2006 09:57 UTCUwe Kolitsch Manager

Fleischerite photo (http://www.mindat.org/photo-79515.html) changed to dundasite and comment added.

23rd Nov 2006 10:02 UTCKnut Eldjarn 🌟 Manager

Hi Brent,

The lack of comments from other Mindat-contributors to your questions concerning the correct ID of the 2 photos of Tsumeb-minerals from Jason probably reflects that there are some of us who agree with your views and with interest follow the thread and look forward to results of further analysis/documentation. I have similar Tsumeb-specimens in my collection in part originally wrongly labelled and have personally commented the issue to Jason directly. But maybe a comment from the Mindat-board executive responsible for approving the pictures could be appropriate?

Knut

23rd Nov 2006 20:23 UTCRobert Meyer Manager

I noticed mention of the fleischerite photograph took a look. For what it is worth the association with azurite and general appearence are very typical of dundasite specimens from Tsumeb that I have. I don't have a fleischeite, but the ones I have seen don't look like the photograph.

Bob

23rd Nov 2006 22:07 UTCJason B. Smith Expert

Thanks all. Have been away for some time because of work. Wouldve changed the photos myself if I would have been able to catch the thread. Thanks all, will relabel my specimens. I have one question though, wouldnt dundasite react in HCL? These fibers do not. Thanks, Jason.

18th Jul 2010 17:13 UTCUwe Kolitsch Manager

Just X-rayed a "fleischerite" in our collection (NHM Vienna), which was bought in 1978 (accompanying label gives the previous owner as Georg Gebhard). As expected, it turned out to be dundasite. The price at that time was 6,000 Austrian Schillings...

The specimen shows white to pale blue sprays on azurite and reticulated cerussite, similar to the specimens shown on http://www.mindat.org/photo-79515.html and http://rruff.info/dundasite/names/asc/R090038. Under high magnification the crystals show a lath-like morphology which alone clearly would have excluded fleischerite (hexagonal).

Another small "fleischerite" specimen bought in the same year from Okavango minerals (Rolf Fahle) looks identical.

18th Jul 2010 22:08 UTCRobert Meyer Manager

Since my earlier posts, I did obtain a specimen labeled fleischerite. I will have a grain analyzed sometime in the future and report back.

Bob

14th Feb 2013 16:54 UTCLefteris Rantos Expert

http://www.mindat.org/photo-389505.html

I'm quite confident that this is a similar case as the original "Schaurteite" of this thread...

Lefteris.

21st Feb 2013 11:32 UTCUwe Kolitsch Manager

Message sent.

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