Magnetite is a ferrimagnetic mineral with actinic blueprint Fe3O4, one of several adamant oxides and a affiliate of the spinel group. The actinic IUPAC name is iron(II,III) oxide and the accepted actinic name is ferrous-ferric oxide. The blueprint for magnetite may aswell be accounting as FeO·Fe2O3, which is one allotment wüstite (FeO) and one allotment hematite (Fe2O3). This refers to the altered blaze states of the adamant in one structure, not a solid solution. The Curie temperature of magnetite is 858 K (585 °C; 1,085 °F). It is atramentous or brownish-black with a brownish luster, has a Mohs acerbity of 5–6 and a atramentous streak.
Magnetite is the a lot of alluring of all the by itself occurring minerals on Earth.Naturally magnetized pieces of magnetite, alleged lodestone, will allure baby pieces of iron, and this was how age-old humans aboriginal noticed the acreage of magnetism. Lodestones were acclimated as an aboriginal anatomy of alluring compass. Magnetite about carries the ascendant alluring signature in rocks, and so it has been a analytical apparatus in paleomagnetism, a science important in advertent and compassionate bowl tectonics and as celebrated abstracts for magnetohydrodynamics and added accurate fields. The relationships amid magnetite and added iron-rich oxide minerals such as ilmenite, hematite, and ulvospinel accept been abundant studied, as the complicated reactions amid these minerals and oxygen access how and if magnetite preserves annal of the Earth’s alluring field.
Magnetite has been actual important in compassionate the altitude beneath which rocks form. Magnetite reacts with oxygen to aftermath hematite, and the mineral brace forms a absorber that can ascendancy oxygen fugacity. Commonly, ablaze rocks accommodate grains of two solid solutions, one amid magnetite and ulvospinel and the added amid ilmenite and hematite. Compositions of the mineral pairs are acclimated to account how acerbic was the magma (i.e., the oxygen fugacity of the magma): a ambit of acerbic altitude are begin in magmas and the blaze accompaniment helps to actuate how the magmas ability advance by apportioned crystallization.
Small grains of magnetite action in about all ablaze and metamorphic rocks. Magnetite aswell occurs in abounding sedimentary rocks, including affiliated adamant formations. In abounding ablaze rocks, magnetite-rich and ilmenite-rich grains action that precipitated calm from magma. Magnetite aswell is produced from peridotites and dunites by serpentinization.