Vauxite , Paravauxite , Metavauxite , Wavellite Locality: Siglo Veinte Mine (Siglo XX Mine; Llallagua Mine; Catavi), Llallagua , Rafael Bustillo Province , Potosí Department , Bolivia ( Locality at mindat.org ) Size: 8.7 x 7.5 x 2.1 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 micro crystals 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 are a 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. This particular piece is a remarkable, very well crystallized, very rare specimen consisting of small, bladed, beautiful blue color, 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. It is very difficult to obtain any specimens of this incredibly beautiful phosphate and to find all three "Vauxites" together on one piece is amazing. 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. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Metavauxite
Metavauxite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Fe²⁺Al₂(PO₄)₂(OH)₂·8H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1/c).
Key properties: Mohs hardness 3; specific gravity 2.345; Vitreous to silky in aggregates luster; optically biaxial.
IMA symbol Mvx, grandfathered status — known before the IMA’s founding, named in 1927.
Occurs as an uncommon secondary mineral in the oxidized zone of tin mines.
It is found associated with Vauxite, paravauxite, wavellite, quartz.
In allusion to the chemical relation to vauxite.