Delvauxite, also known as borickite, is a yellow to brown to dark brown amorphous , sometimes forming a botryoidal Its chemical formula is CaFe 4(PO 4,SO 4) 2(OH) 8•(4-6)H 2O. and it may sometimes form stalactites.
It was first described in 1838 by Belgian chemist, Dumont and dedicate to J.S.P.J. Delvaux de Fenffe (1782–1863). It was found in Bernau, Liege, Belgium and Stredocesky, Czech republic