Vauxite with Franckeite on Pyrite (plus at least 7 other species!) (ultra-rare association specimen!)

Siglo XX mine, Llallagua, Bustillo Province, Potosi Department, Bolivia (type locality for four species)
Small Cabinet, 7.8 x 7.1 x 6.2 cm
Start Time: 10/28/2010 6:45:00 pm (CDT)
End Time: 11/04/2010 6:45:00 pm (CDT)
Auction Closed

Item Description

From the find of 2006, this is undoubtedly one of the most significant and momentous discoveries ever made at this locality. Not since the days of World War II has there been such a remarkable find of this material. This particular specimen is one of the richest assocaition pieces that I have seen from Siglo XX. First, one can see that the piece is coated with beautiful, delicate, light blue, bladed crystal aggregates of Vauxite which are sitting on a large Pyrite crystal. That association in an of itself is rare for this locality, as Vauxites are not often seen ON Pyrite. Secondly and perhaps most importantly, there are several areas on the specimen where one can clearly see metallic grey blades and radiating groups of the rare sulfosalt Franckeite! This is clearly the only locality in the world where Vauxite and Franckeite are found together. Under high magnification, one can see a plethora of species which include, very pale green to white bladed crystals of Paravauxite, some of which have altered to tan/brown Sigloite crystals. Additionally there are hundreds of acicular "needle"-like strands of colorless Metavauxite which are typically intergrown with colorless, gemmy Quartz crystals and small radiating groups of white Wavellite. While poking around, I discovered a small patch near the center of the specimen that plays host to several intense red color GREENOCKITE crystals! Greenockite is one of the most highly sought after and well-known micro species from Siglo XX, and this is the first specimen I have seen with Vauxite and Greenockite together. Lastly, there are some small white to cream colored somewhat spherical groups of what could possibly be Crandallite or Alunite, but would have to be analyzed to confirm its identity. This piece hosts at least TEN SPECIES, and with some time under the microscope, I would say that it is certainly possible that more could be found. I spent at good 20 minutes looking at the piece, and taking tons of micro photos as you can see. It should be noted that the Siglo XX mine is the type locality for four of the species on this pieces; Vauxite, Paravauxite, Sigloite and Metavauxite. If you're a micro collector, or a collector of Bolivian minerals, or if you have an interest in multi-association specimens, do not pass up this one-of-a-kind piece. It is certainly unlike anything I have seen from this historic and prolific locality!

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