The main component of magnetite Fe3O4, crystal is equiaxed oxide minerals, crystals often has octahedron and rhombic dodecahedron, collection of grainy or lumpy. Intact monocrystalline octahedral or rhombic dodecahedron, was when the rhombic dodecahedron, parallel stripes of the diamond crystal surface often face long diagonal direction. Dense block or granular aggregates. Color iron black, streak black, metallic or semi-metallic luster, opaque, no cleavage, hardness 5.5-6, the proportion of 4.8-5.3. Because it has a strong magnetic Ancient China Ancient China called magnet, magnetic characterization of it; in addition there resemble stone, magnets, Kuroishi other names. Iron content of 72.4%, is the most important iron ore. Ores containing harmful elements such as small, open-hearth can be used directly. Many magnetite accompanied by titanium, vanadium, chromium and other elements, the smelting process can utilization. One of magnetite or traditional Chinese herbal medicine, Chinese medicine has a sedative effect. Magnetite crystals with inverse spinel structure (see spinel). Single crystals often has octahedron also rhombic dodecahedron, twinning common was massive or granular aggregates. Iron black, semi-metallic luster, sometimes with octahedral parting. Morse hardness of 5.5 to 6.5, the proportion of 5.2, with ferrimagnetic, is the strongest magnetic minerals can be attracted by the permanent magnet. Having magnetic poles can attract iron needles and other objects called pole magnetite. Chi, also known as rock, magnets, Kuroishi. Is the strongest magnetic minerals, can be permanent magnets attract, the ancient Chinese compass, "Ian," is to use this feature made. After oxidation becomes hematite or limonite. Magnetite crystals often has octahedron and rhombic dodecahedron, collection of grainy or lumpy. Is the strongest magnetic minerals, can be permanent magnets attract, after oxidation becomes hematite or limonite.