The Paratoo Copper Mine, an old, small copper mine is South Australia, is well-known for a highly unusual assemblage of secondary REE and Cu-REE carbonate minerals. It is the Type Locality and only locality in the world for decrespignyite-(Y). Bright, pretty, sky-blue crusts of decrespignyite-(Y) richly cover the thin, cleavage plate of matrix. This is a very rich and highly representative example of the very rare species and locale; this is a large and very significant specimen.