Any of a group of commonly happening yellowish-brown to black iron-oxide nutrients, essentially FeO(OH)·nH2O, made use of as a minor ore of metal.
any of several normal hydrous iron oxides; often an assortment of goethite and hemite with clays and manganese oxide
Hydrous sesquioxide of metal, an essential ore of iron, happening in stalactitic, mammillary, or earthy types, of a dark brown shade, and yellowish brown powder. It provides bog-iron. Also referred to as brown hematite.
a significant iron ore which will be discovered natural, concretionary, or mammillary and fibrous.
a widely happening iron-oxide ore; an assortment of goethite and hematite and lepidocrocite