hydroxide type
Brucite type
brucite
hexagonal, Mg(OH)2
manganite
monoclinic, MnO(OH)
goethite
orthorhombic, FeO(OH)
romanechite
orthorhombic, BaMn2Mn3O16(OH)4
Gibbsite type
diaspore
orthorhombic, AlO(OH)
boehmite
orthorhombic, AlO(OH)
Gibbsite
monoclinic, Al(OH)3