magnetite

mag·net·ite

M0032500 (măg′nĭ-tīt′)n. The mineral form of black iron oxide, Fe₃O₄, that often occurs with magnesium, zinc, and manganese and is an important ore of iron.

magnetite

(ˈmæɡnɪˌtaɪt) n (Minerals) a black magnetic mineral, found in igneous and metamorphic rocks and as a separate deposit. It is a source of iron. Composition: iron oxide. Formula: Fe3O4. Crystal structure: cubic magnetitic adj

mag•net•ite

(ˈmæg nɪˌtaɪt)

n. a common black mineral, ferrous and ferric iron oxide, FeFe₂O₄, that is the most magnetic mineral and an important iron ore. [< German Magnetit (1845); see magnet, -ite¹]

mag·net·ite

(măg′nĭ-tīt′) A usually brown to black, magnetic mineral composed of iron and magnesium oxide. Magnetite occurs in many different types of rocks, commonly as small octahedrons. It is an important source of iron.

Thesaurus

Noun

magnetite - an oxide of iron that is strongly attracted by magnetsmagnetic iron-oreemery - a hard grey-black mineral consisting of corundum and either hematite or magnetite; used as an abrasive (especially as a coating on paper)iron ore - an ore from which iron can be extractedloadstone, lodestone - a permanent magnet consisting of magnetite that possess polarity and has the power to attract as well as to be attracted magnetically

Translations

магнетит

magnetite

(măg`nətīt), lustrous black, magnetic mineral, Fe₃O₄. It occurs in crystals of the cubic system, in masses, and as a loose sand. It is one of the important ores of iron (magnetic iron ore) and is a common constituent of igneous and metamorphic rocks. It is found in Norway, Sweden, the Urals, and various parts of the United States. A variety of magnetite, lodestone (or loadstone) exhibits polarity and is especially interesting for its natural magnetism; Magnet Cove, Ark., became famous as a source.

Magnetite

a mineral, a complex oxide of composition FeO.Fe₂O₃, containing 31 percent FeO and 69 percent Fe₂O₃ (a total of 72.4 percent Fe), and frequent admixtures of MgO, Cr₂O₃, Al₂O₃, MnO, and ZnO. Magnetite is a ferrite and has the inverse spinel structure. It crystallizes in the isometric system a₀ = 8.3963 Å, generally forming octahedral, more rarely dodecahedral, crystals and granular aggregates. Magnetite rarely occurs in the form of colloform aggregates.

Synthesized magnetite is widely used in industry. It is usually obtained by synthesis in the solid phase following the combined roasting of pressed FeO and Fe₂O₃ powders at temperatures of 1000-1400°C

Magnetite is brittle with an uneven fracture; it exhibits no cleavage. It has a hardness of 5.5-6 on Mohs’ scale and a density of 4,800-5,300 kg/m³. A black mineral, it is opaque, and has a semimetallic, sometimes dull, luster. A good conductor of electricity, magnetite is classified as a ferrimagnet owing to its magnetic properties. Its magnetization is determined by the difference in magnetic moments of the mineral’s two magnetic sublattices: (1) composed of Fe²⁺ and Fe₃₊ ions, located at the octahedral points, and (2) composed of Fe₃₊ ions, located at the tetrahedral points. At room temperature, the saturation magnetization of magnetite is J_s = 4.8 ×10² tesla (480 gauss). The coercive force H_c of natural magnetite depends on the admixture content, while that of synthesized magnetite is conditioned by the method used to obtain the magnetite. In magnetite powders, H_c increases with decreasing particle size [in fine powders, H_c ~ 12-16 kA/m (150-200 oersteds)]. Magnetodielectrics are manufactured from these powders. At temperatures above 550-600°C (above the Curie point), magnetite becomes paramagnetic. Magnetite has a melting point of 1591-1597°C. Oxidation of magnetite leads to hematite (martite); muschketowite is the pseudomorph of magnetite after crystalline hematite. Varieties of magnetite are distinguished as a result of increased content of isomorphic admixtures: magnesioferrite, manganmagnetite, vanadomagnetite, chromian magnetite, and aluminian magnetite. Magnetite is included in the titanomagnetite category when found in close penetration with ilmenite and other titanium minerals (decomposition structure of solid solutions).

Magnetite occurs in deposits of various origins; however, the main industrial deposits are located in complex magmatic, con-tact metasomatic, or regional metamorphic formations. Magnetite frequently occurs in magmatic, sedimentary, and metamorphic rocks as an accessory mineral.

V. M. GRIGOR’EV

magnetite

[′mag·nə‚tīt] (mineralogy) An opaque iron-black and streak-black isometric mineral and member of the spinel structure type, usually occurring in octahedrals or in granular to massive form; hardness is 6 on Mohs scale, and specific gravity is 5.20. Also known as magnetic iron ore; octahedral iron ore.

magnetite

A natural black oxide of iron, containing from about 65 to 72% iron and sometimes a small amount of nickel and titanium; used as an aggregate in high-density concrete.

magnetite

a black magnetic mineral, found in igneous and metamorphic rocks and as a separate deposit. It is a source of iron. Composition: iron oxide. Formula: Fe₃O₄. Crystal structure: cubic

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Synonyms for magnetite

noun an oxide of iron that is strongly attracted by magnets

Synonyms

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