Rhodochrosite

Here's a candidate for the Best Rhodochrosite gallery:

Kounrad Massif, Balqash (Balkhash; Karatas; Prebalkhashie) Region, Zhezqazghan Oblysy (Dzezkazgan Oblast'; Dzhezkazgan Oblast'; Djezkazgan Oblast'; Jezkazgan Oblast'), Kazakhstan

Superb rare and colorful association of rhodochrosite with white bertrandite sprays and purple fluorite. Carnegie Museum of Natural History specimen CM27368. 13.5 x 8.5 cm. Photo by Debra Wilson, used by permission.

Woodrow,
I agree entirely. I have put it in the article. I wonder if it is from the same locality as the other one we have from Kazakhstan.

Rock Currier
Crystals not pistols.

Good morning Rock,

I think these two Kazakhstan rhodo localities are different. I suspect (and vaguely recall reading somewhere) that the botryoidal crusts are found in a stratiform manganese ore deposit of sedimentary origin. We have a similar deposit in northern Maine, though it doesn't produce attractive specimens. Some of these Kazak rhodos have been overcleaned within an inch of their lives. You can see the whizz marks and botryoids that were worn down flat by over-zealous use of a grinding wheel or wire brush!

Those beautiful combos of rhodo crystals with betrandite, fluorite, and apatite are really amazing specimens! The betrandite-rhodo association is described in a 1960 book, "Geochemistry of Beryllium" by A. A. Beus, which was reprinted in a 1966 English translation (W. H. Freeman publisher). They were practically giving these books away at geology meetings a while back, yet they contain a wealth of info on Be minerals and their geologic environments. In the chapter on "hydrothermal-pneumatolytic beryllium deposits", Beus says that "Distinct corrosion and replacement of helvite with carbonates, especially rhodochrosite, is accompanied by the formation of bertrandite and late sulfides." I've seen pyrite on a lot of Kazak rhodo-bertrandite specimens, so that description fits.

Now we just need to hear from somebody who's actually been there (maybe Pavel?).

Best,
Woody Thompson
Maine Geological Survey



Edited 1 time(s). Last edit at 03/30/2009 01:15PM by Woodrow Thompson (2).

I suspect that I will want to put a reference to that source in the article as well.

Rock Currier
Crystals not pistols.

Rock,
i started uploading pictures of classic german rhodos meanwhile ...
most beautiful AFAIT until now is [www.mindat.org] .. and it is one of the best specimens from Oberneisen i have seen personally until now. Still some in the pipeline to be photographed but still have to convince the owner.
Just working on Wolf mine and Oberneisen mine descriptions .. and a few more .. will last a bit as i only can do this during spare time .. which is rare at the moment. If you need any special requirements please let me know,
cheers
Roger

Rock:

There are at least six major Rhodo specimen localities missing from your list:

Uchucchacua Mine, Oyon Province, Peu

Santa Rita Mine, Yauli Province, Peru

Hotazel Mine, Kalahari Manganese Fields, South Africa

Champion Mine, Hinsdale County, Colorado

Eagle (Eagle-Hawk) Mine, Saguache County, Colorado

Granite-Bimetallic (Granite; Bimetalic) Mine, Granite County, Montana

In addition, in the Ukraine deposit Clam, Mussel and Gastropod pseudo's also occur and at Herdorf one must also include the excellent deep red scalenohedra "spike" aggregates on matrix.

Frank.

Frank,
Wolf mine, Herdorf, is at work

cheers
Roger

Roger,
Yes, I agree and in it goes. Can you tell us something about the mine, its geological setting and how many specimens were found and when?

Rock Currier
Crystals not pistols.

Rock,
please gimme some time .. i just sorted out the literature and will make an abstract asap,

cheers
Roger

Francis,
Yes, thanks for the suggestions. Am still scratching my head trying to figure out why I missed Uchucchacua Mine. A couple of the other localities appear not to have any pictures of Rhodochrosite posted. Would you perhaps be able to upload pictures of rhodochrosites from those localities? Ill try and get around to adding them to the article soon. Keep the suggestions coming.

Rock Currier
Crystals not pistols.

Rock,
another picture that may be interesting for the article .. [www.mindat.org]

still working on some mine description so please be longanimous with me

Cheers
Roger

Roger,
Yeikes! Im starting to think Germany is built on a giant rhodochrosite deposit. Yes, I think that picture and locality is worth of inclusion. The whole rhodochrosite article is in need of revamping at this point. Sigh!. Another five hours down the drain. But it must be done if it is to be a worthy article. I may wait a bit to see what other suggestions show up and work them into the article all at the same time.

Can you tell something of the history of the mine, what kind of mine it is (was?) and how abundant the rhodochrosite specimens were from there?

Rock Currier
Crystals not pistols.



Edited 1 time(s). Last edit at 04/02/2009 02:26AM by Rock Currier.

Rock,

That fine specimen in the latest German rhodochrosite photo submitted by Roger is remarkably similar to the botryoidal Kazakhstan material you were asking about. Amazingly, it's on a limestone matrix, which suggests that a sedimentary rock host is plausible for the Kazak rhodos too. I'll look around and see if I can find more info on the latter.

Woody Thompson



Edited 1 time(s). Last edit at 04/02/2009 12:11PM by Woodrow Thompson (2).

Rock,

In fact, most of the mines in the Siegerland have produced fine rhodochrosites - often in minor quantities and not all of them in outstanding quality, but they did. For instance, Frauenberger Einigkeit and others produced specimens with rhodochrosite and malachite side by side - an intriguing combination. The Wolf mine (which also produced decent millerites !) probably owes its fame to the abundance of high quality specimens, but there were many other mines that produced comparable or even better material. In the west an further south, the area is adjoined by rich lead mining districts that produced remarkable pyromorphites. Thus, there are many collectors in the area who are concentrating their interests on rhodochrosite and/or pyromorphite (elsewhere known as the "red-green mafia").)


Woody,

Host rocks in the Siegerland mining district are mainly Devonian slates. The deposits consist of siderite veins (occasionally with other carbonates) that also include sulphides (mainly Pb-Zn-Cu, minor Co-Ni). The outcrops on surface (altered to iron oxides) gave rise to iron mining since the middle ages. In fact, the mines were mainly worked for iron ores (mainly siderite) to feed the smelters in the Ruhrgebiet, where rich coal deposits are located.



Edited 3 time(s). Last edit at 04/02/2009 05:01PM by Peter Haas.

Rock,

The following book contains a selection of spectacular photographs of rarities from the collections at Mainz, focussing on minerals from Rhineland-Palatinate (incl. western Siegerland, Bad Ems, the mercury deposit near Obermoschel and other mining districts) and neighbouring areas:

Poser, C., and Lutz, H. (2004): Mineralien aus Rheinland-Pfalz. Landessammlung für Naturkunde (Mainz), 80 pp. (in German)

Highly recommended !

Peter,
We need some of the Red and Green Mafia to share some images of their treasures with us so we can get them into the articles. Ill see if I can find a copy of the Poser, C., and Lutz, H. (2004): Mineralien aus Rheinland-Pfalz. Landessammlung für Naturkunde (Mainz), 80 pp. (in German) to buy. Do you know someone selling it, or is it out of print?

Rock Currier
Crystals not pistols.

Peter,
glad you noticed Poser, C., and Lutz, H. (2004): Mineralien aus Rheinland-Pfalz - very good overview and i was glad to follow the "genesis" of the book.
The Heinricherz rhodochrosite picture [www.mindat.org] is taken out of this book. I phoned with Herbert Lutz yesterday and he granted me to upload the pictures of the book (had a few digital copies in advance) and we will meet after the Easter holidays to check all 6 or 7 CDs with pictures of the Landessammlung. I hope to get pictures of the famous Victor Goldschmidt collection online as well as from the famous Rheinpfalz-collection of Arndt, Reis & Schwager - so probably good stuff for the "best of" articles. Particularly the rhodochrosites from Wolf mine out of the former Runkel collection are REALLY interesting. But i also want to give (at least) a short description of the mines and their history ... so this will continue for some weeks as i do this in my spare time.

Rock and Woody .. please see these pictures as other examples of the book and to get an impression what may come subsequently.
[www.mindat.org]
[www.mindat.org]
[www.mindat.org]
[www.mindat.org]

Cheers
Roger

Hi Roger,

Those are excellent specimens and photos, thanks! It will be very interesting to see the other minerals featured in the book.

Woody Thompson

Woody,
at this time i should credit the photographer, Christof Poser who took all these pictures i have the opportunity to upload now. Unfortunately Christof is not longer at the Naturhistorisches Museum and i lost contact since then.

And yes .. i am very curious about the digipics i haven´t seen until now,

cheers
Roger

That's fantastic news !

And a good occasion to remind you of a minor error in the book: the locality for picture 132 is given as "Battenberg, Hessen". It's actually Battenberg near Bad Dürkheim. Hans-Peter Schröder had an article in Pollichia a couple of years ago, dealing with the "lost localities" around Battenberg, i.e. the type locality of calcioferrite and the baryte deposit, which might be actually the same place. He also tried to locate the baryte deposit in the field, but had no luck at all.