Clara Mine, Rankach valley, Oberwolfach, Wolfach, Black Forest, Baden-Württemberg, Germany

Barite-fluorite veins including copper, silver and lead minerals, hosted by gneisses and triassic sandstones. The mine was started in 1726 and is presently owned by the Sachtleben company, who works it for barite and fluorite (and occasionally silver ore). In 2004, the 700 m underground level was reached.

Located in the upper Rankach valley, about 7 km north of Oberwolfach and about 9 km north of Wolfach. The dumps and processing plant are located in the Kinzig valley near Hausach, about 1 km south of Wolfach. Permission and fee are required to collect on the dumps (prior to june 2007 this was possible Mo-Th 9 am - 5 pm and Fr 9 am - 2 pm).

IMPORTANT NOTE (June 2007): A change to the collecting policy was introduced by the Sachtleben company in June 2007: collecting is now only allowed in a fenced-in area of the dumps, in a new spot next to the processing plant.
Collecting is possible from 9 am to 5 pm, also on weekends (new truckloads of material will be brought in regularly).
Children are allowed to collect (previously only persons aged 18 and over are allowed to collect). The collecting fee is 8 Euro for ages 15 and above, and 4 Euro for ages 14 and below; 8 kg of material is free, each excess kg costs 50 cents.
Access is possible until the end of October 2007, thereafter during the winter months only from Thursday to Saturday, 9 am to 5 pm (previously collecting in winter time was only after appointment with one of the organisers (see http://www.mineralienhalde.de/ - website online since August 22, 2008); groups are preferred.
(Details in German:
http://www.mineralienhalde.de/, http://www.mineralienatlas.de/lexikon/index.php/Deutschland/Baden-W%FCrttemberg/Schwarzwald/Wolfach/Grube%20Clara and http://www.clara-mineralien.de/)



IMPORTANT NOTES on the mineral list (regularly updated by Uwe Kolitsch):

- The osarizawaite described from the Clara mine [SCHNORRER-KÖHLER, G. (1988): Osarizawait, PbCuAl2(SO4)2(OH)6, ein Mineral der Alunit-Beudantit-Crandallit-Gruppe aus der Grube Clara im Schwarzwald. - Aufschluss, 39 (1), 49-51. (in German)] later was found to be a complex solid-solution member of the crandallite group instead [KOLITSCH, U., BLASS, G., GRAF, H.-W. & GRÖBNER, J. (2004): Neufunde aus der Grube Clara im mittleren Schwarzwald. Lapis 29 (2) 18-23; 50. (in German)]

- Reported (and sold) mckinstryite is highly questionable [KOLITSCH, U., GRÖBNER, J. BLASS, G., GRAF, H.-W. & PRING, A. (2005): Neufunde aus der Grube Clara im mittleren Schwarzwald (II): Dreyerit, Gasparit-(Ce), Klinobisvanit, Kobaltkoritnigit, Metatyuyamunit, Roscoelith, Sengierit, Vésigniéit und Wakefieldit. Lapis 30 (9), 35-39; 58.]

- Reported zinckenite is highly questionable [Walenta, K. (1992): Die Mineralien des Schwarzwaldes. Weise (Munich), 336 pp. (in German)]

- Reported greenockite [Kaiser, H. (1984): Die Grube Clara zu Wolfach im Schwarzwald. Verlag Karl Schillinger, Freiburg im Breisgau, 102 pp. (in German)] was found to be amorphous CdS ("Xantochroite").

- Reported "rhabdophane-(La)" is unconfirmed so far.

- Reported "fluocerite-(La)" is unconfirmed; all samples analysed so far were Ce-dominant.

References:
Selected references:

- Walenta, K. (1975) The secondary minerals of the barite vein of the Clara mine near Oberwolfach, central Black Forest. Aufschluss, 26, 369-411. (in German)
- Kaiser, H. (1984): Die Grube Clara zu Wolfach im Schwarzwald. Verlag Karl Schillinger, Freiburg im Breisgau, 102 pp. (in German)
- Rocks & Minerals: 56: 233.
- Rocks & Minerals: 62: 320.
- Rocks & Minerals: 65: 448-454.
- Huck, K. (1984): Die Beziehungen zwischen Tektonik und Paragenese unter Berücksichtigung geochemischer Kriterien in der Fluß- und Schwerspatlagerstätte "Clara" bei Oberwolfach/Schwarzwald. Ph.D. Thesis, Ruprecht-Karls-Universität Heidelberg. (in German)
- Walenta, K. (1992): Die Mineralien des Schwarzwaldes. Weise (Munich), 336 pp. (in German)
- Kolitsch, U., J. Gröbner und R. Bayerl (1995): Die Mineralien der Silber-Antimon-Vererzungen der Grube Clara im Zeitraum 1993 bis 1995. Erzgräber 9 (2), 61-77. (in German)
- Preite, D. and Cini, V. (1997): La miniera di Grube Clara. Rivista Mineralogica Italiana 1997 (1), 19-49. (in Italian)
- Lapis 8(7/8), 11-36. (in German)
- J. Gröbner und U. Kolitsch (1999): Mineralien- und Literaturliste der Grube Clara bei Oberwolfach. Erzgräber 13 (1), 1-13. (in German)
- Kolitsch, U., und M. Götzinger (2000): Einige Neufunde aus der Grube Clara im mittleren Schwarzwald: Eulytin, Namibit, Volborthit, Gearksutit, Spertiniit, Monazit-(La), Protasit, Sainfeldit, Cyanotrichit und Vauquelinit. Erzgräber 14, 33-47. (in German)
- Kolitsch, U. (2000): Eine durch Betoneinwirkung entstandene Paragenese von Blei-Verbindungen aus der Grube Clara im mittleren Schwarzwald. Erzgräber 14, 48-53. (in German)
- Wendel, W., Bayerl, R. & Oppelt, W. (2001): Die Mineralien der Grube Clara bei Oberwolfach. Lapis 26 (7-8), 27-54. (in German) [part of Lapis special issue on the Clara mine]
- Zhu, Y., Merkel, B. J., Stober, I. and Bucher, K. (2003): The hydrogeochemistry of arsenic in the Clara mine, Germany. Mine Water and the Environment 22, 110-117.
- Kolitsch, U., G. Blaß, H.-W. Graf und J. Gröbner (2004): Neufunde aus der Grube Clara im mittleren Schwarzwald. Lapis 29 (2) 18-23; 50. (in German)
- Werner, W. & G. Markl: (2005): Hydrothermalgänge im Schwarzwald – Bergbau, Entstehung und Lagerstättenpotenzial. Mitt. Österr. Mineral. Ges. 151, 121. (in German)
- Kolitsch, U., J. Gröbner, G. Blaß, H.-W. Graf und A. Pring (2005): Neufunde aus der Grube Clara im mittleren Schwarzwald (II): Dreyerit, Gasparit-(Ce), Klinobisvanit, Kobaltkoritnigit, Metatyuyamunit, Roscoelith, Sengierit, Vésigniéit und Wakefieldit. Lapis 30 (9), 35-39; 58. (in German)
- Gröbner, J., Kolitsch, U. & Bayerl, R. (2005): Interessante Uranmineralien im Stinkspat der Grube Clara. Lapis 30 (10), 34-39; 90. (in German)
- Gröbner, J, Bayerl, R. & Kolitsch, U. (2006): Weitere Beobachtungen zu den Uran- und Vanadium-Paragenesen der Grube Clara aus den Jahren 2002, 2004 und 2005. Erzgräber 20, 1-10. (in German)
- U. Kolitsch, J. Gröbner, G. Blaß and H.-W. Graf (2007): Neufunde aus der Grube Clara im mittleren Schwarzwald (III): Cerianit-(Ce), Dravit, Florencit-(La), Gilmarit, Olenit und Scotlandit. Lapis 32, 19-23, 70. (in German)
- G. Blass, H.-W. Graf and D. Sebold (2009): Neue Mineralien von der Grube Clara im Kinzigtal. Mineralien-Welt 20 (1), 87-89. (in German)

For complete and regularly updated lists of references see:
- http://www.rbmineral.de/claraliteratur.htm
- http://www.clara-mineralien.de/verein/publicity/erzgraeb/index.html

For mineral lists (with photographs) see also:
- http://www.rbmineral.de/rb3.htm
- http://www.grube-clara.com/Clara_Mineralien/clara_mineralien.html
- www.clara-mineralien.de
- http://www.strahlen.org/vp/de/clara/
- http://www.mineralienatlas.de/lexikon/index.php/Deutschland/Baden-W%FCrttemberg/Schwarzwald/Wolfach/Grube%20Clara

For updates on recent finds on the dumps see:
- http://www.clara-mineralien.de/mineralienhalde/fundeaktuell/index.html