Moolooite is a rare blue-green mineral with the formula Cu(C2O4)·n(H2O) (n<1) (copper(II) oxalate hydrate). It was discovered in Bunbury Well, Mooloo Downs station, Murchison, Western Australia in 1986.<ref name=clarke-williams>Template:Cite journal</ref> It has an orthorhombic crystalline structure, and is formed by the interaction of bird guano with weathering copper sulfides.
A second occurrence is reported from the Sainte-Marie-aux-Mines silver mining district of Vosges Mountains, France.<ref name=clarke-williams/>