These essentially uniformly colored, lightweight clusters of Vauxite are unusual and beautiful material that formed as thin crack fillings in a strange environment at the Siglo Veinte Mine yielding what are unquestionably the world's best of species. This is a double-sided piece with mounded, radial aggregates on both sides composed of spiky, bladed, beautiful blue crystals that sparkle everywhere. It has been decades since any good ones were found and this is a style that dates back to the 1960's or before. I have only seen these of such quality in old collections. Vauxite is a hydrated iron-aluminum phosphate and the Siglo Veinte Mine is the type locality. A rare old classic from the Bob Reynolds collection.