Les Montmins Mine (Ste Barbe vein), Échassières, Ébreuil, Allier, Auvergne, France

Early 20th century tungsten mine, working wolframite-bearing quartz veins hosted by micaceous slates and granite. Located about 3 km NE of Echassières.
Famous for a wealth of well-crystallised secondary oxysalt minerals (mainly phosphates and arsenates).


NOTE on the published mineral photos:
- The photo of "mawbyite" published in Boisson et al. (2000) most probably shows a carminite. Single-crystal XRD studies of crystals with identical shape showed them to be carminite (Uwe Kolitsch, unpublished results).
- The dufrénites shown in the locality photo gallery here on Mindat may in part be natrodufrénite (probably none of them has been analysed (semi-)quantitatively).

References:
- Aubert, G. (1969): Les coupoles granitiques de Montebras et d'Echassières (Massif Central Français) et la genèse de leurs minéralisations en étain, lithium, tungstène et béryllium. Mémoires du BRGM N°46, 345 pp.
- Walenta, K. & Binder, W. (1980): Kidwellit und Dufrenit aus den Mines de Montmins bei Echassiéres (französisches Zentralmassiv). Aufschluss 31, 51-54.
- Boisson, J.-M., Leydet, J.-C., Queneau, P., Revel, C. & Valverde, J. (2000): Filon Sainte-Barbe, Commune d'Echassières (Allier, France). Le Cahier des Micromonteurs, No. 4, 3-46. (in French)
- Cuchet, S., Brugger, J., Meisser, N., Ansermet, S. & Chiappero, P.-J. (2000): Les minéraux du filon Sainte-Barbe, Les Montmins, Allier. Le Règne Minéral, (33), 5-25. (in French) http://www.strahlen.org/magspublic/lrm/lrm-2000-0506-05-frankrijk-allier-montmins.pdf]
- Mestrom, P. (2009): De mineralen van Les Montmins: klein maar fijn. GEA, 42 (1), 10-14.
- Kolitsch, U., Gröbner, J. & Brandstätter, F. (2009): Neufunde von Les Montmins, Allier, Frankreich. Lapis 34 (11), 24-32; 54 (in German).

- http://www.strahlen.org/vp/fr/montmins/montmins.htm