Metavauxite is a very rare supergene secondary phosphate mineral found in the oxidized zone of only two tin mines in the world, both in Bolivia. Metavauxite is the rarest of the related vauxite family members: paravauxite; metavauxite; and vauxite. It is a monoclinic dimorph of the already rare paravauxite, with clearly different crystal habit when seen in person. This is an exquisite cluster of sharp, pastel-green crystals from the Type Locality - the Siglo Veinte Mine at Llallagua. This specimen almost certainly dates to when Mark Bandy recovered the best material in the mid 1900s. Ex. Carl Davis Collection.