Delvauxite

Delvauxite, also known as borickite, is a yellow to brown to dark brown amorphous mineral, sometimes forming a botryoidal mass.^[2] Its chemical formula is CaFe
₄(PO
₄,SO
₄)
₂(OH)
₈•(4-6)H
₂O.^[3] and it may sometimes form stalactites.

Delvauxite
General
Category	Phosphate minerals
Formula	CaFe 4(PO 4,SO 4) 2(OH) 8•(4-6)H 2O
IMA symbol	Dvx[1]
Identification
Color	Yellow to brown to dark brown

It was first described in 1838 by Belgian geologist André Dumont and dedicate to chimist Charles Delvaux de Fenffe (1782–1863) who first analysed its chemical composition.^[2] It was found in Bernau, Liege, Belgium and Stredocesky, Czech Republic.^[3]