limonite: A generic term for agroup of hydrous iron oxides,mostly amorphous. Goethite andhaematite are important constituents,together with colloidalsilica, clays, and manganese oxides.Limonite is formed by direct precipitationfrom marine or fresh water inshallow seas, lagoons, and bogs (thusit is often called bog iron ore) and byoxidation of iron-rich minerals. It isused as an ore of iron and as a pigment.
