· Neil D. Opdyke, James E.T. Channell, in International Geophysics, 1996 d Goethite (α-FeOOH). Goethite is the most common of the iron oxyhydroxides and is antiferromagnetic with a disordering (Néel) temperature of about 120°C (Hedley, 1971).Goethite has weak saturation magnetization and very high coercivity (Hedley, 1971; Rochette and Fillion, 1989) …Goethite Mineral | Physical - Optical Properties, Uses, …Goethite is an iron oxide hydroxide, although manganese can substitute for up to 5 percent of the iron. It forms as a weathering product in the oxidation zones of veins of iron minerals, such as pyrite, magnetite and siderite. Goethite may occur with these minerals in the gossan, or iron hat, which is the weathered capping of an iron ore deposit.