Unusual material, these lightweight clusters of vauxite seem to have formed as thin crack fillings in a strange environment, yielding what are unquestionably the world's best of species. It has been decades since any good ones were found, and this is a style that dates back, I think, to the 1960's or before. I have only seen these of such quality in old collections. This particular piece is unusually 3-dimensional, and it has a good sparkle to it, shimmering in light. Underneath, in the reverse, small white crystals of metavauxite are also present. Overall, a rare, 3-dimensional display specimen of a rare species that also happens to be beautiful, from pretty much its only display-worthy locale. Seldom seen for sale, anymore.