Delvauxite
Delvauxite, also known as borickite, is a yellow to brown to dark brown amorphous mineral, sometimes forming a botryoidal mass. Its chemical formula is CaFe4(PO4,SO4)2(OH)8•(4-6)H2O. 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.