Vauxite, Paravauxite, Metavauxite
Siglo Veinte Mine (Siglo XX Mine; Llallagua Mine; Catavi), Llallagua, Rafael Bustillo Province, Potosi Department, Bolivia
Cabinet, 11.5 x 9.5 x 2.0 cm
From the find of 2006, this is undoubtedly one of the most significant discoveries ever made at this locality. Not since the days of World War II has there been such a remarkable find of this material. These are some of the largest overall Vauxite specimens in the world, but the greatest aspect of these pieces is two-fold. First, the Vauxite itself is associated with micro fibrous "strands" of the very rare phosphate Metavauxite, plus tabular microcrystals of Paravauxite and small whitish spheres of Wavellite. It is incredibly rare to have four individual phosphate species all on one specimen, and the fact that this mine is the type locality for Vauxite, Paravauxite and Metavauxite makes it all the better. There are also some small Quartz crystals on most of the specimens found as well, which is really a nice touch to these already amazing pieces. The second significant attribute of these specimens is the fact that they formed on a solid Quartz-Diorite porphyry matrix, and not crumbly clay (after Allophane) which means that they are much sturdier than usual. This particular piece is a remarkable, very well crystallized, ridiculously rare, specimen consisting of small, bladed, beautiful blue, radiating aggregates of Vauxite associated with micro fibrous strands of colorless Metavauxite, along with micro tabular blades of Paravauxite and small whitish spheres of Wavellite plus a few scattered Quartz crystals on firm Quartz-Diorite porphyry matrix. This piece is from the type locality for Vauxite, Paravauxite and Metavauxite which was discovered along the Contacto and San Jose veins in this mine and was first described by Sam Gordon and Mark Bandy.