Joseite (Joseite-A)
Tazna Mine, Potosi Department, Bolivia
Thumbnail, 1.8 x 1.5 x 0.2 cm
This is a downright incredible crystal of this exceptionally rare bismuth tellurium sulfide, from a relatively new locality for the species as brought to market recently by Alfredo Petrov (and the analysis was confirmed by Excalibur Mineral Co. as well as by Marcus Origlieri). These are the largest crystals for the species, of good form, by far. This one, at 1.8 cm, ranks at the very top and is arguably the best single specimen from the lot in terms of both overall size AND the quality/completeness of crystal. Whether this was a onetime find, or whether the mine will produce more (though it hasn't done so in 50 years of mining....), who can say? But, I think it is safe to say that not many could be found, given the unusual nature and rarity of the mineral.