Are the magnets (also called magnets) we see in our lives natural or man-made

Mineral Name. The chemical composition of magnetite Fe3O4, crystal is an isometric crystal system of oxide minerals, crystals are often octahedral and rhombic dodecahedral, aggregates are granular or massive. Intact single crystal shape is octahedral or rhombic dodecahedral, rhombic dodecahedral, the rhombic surface is often parallel to the long diagonal direction of the stripes of the crystal surface. The aggregate is dense block or granular. The color is iron black, the streak is black, metallic luster or semi-metallic luster, opaque, no solubility, Mohs hardness 5.5-6, specific gravity 4.8-5.3. Because of its strong magnetic properties, it is also known as CiShi, Magnetite, and XuanShi in ancient China. It has the strongest magnetic property among the minerals and can be attracted by permanent magnet, and the ancient Chinese compass "Sinan" is made by using this property. After oxidation, it becomes hematite or limonite.

Magnetite is widely distributed and has a variety of causes. Born in metamorphic deposits and endogenous deposits, magmatic cause of the deposits in Sweden, Kiruna as a typical; volcanic action related to the direct formation of magma to the Chilean Lac Iron Ore as a typical; contact metamorphism formed by the formation of iron ore to the Chinese Daye Iron Ore as a typical; iron-bearing sedimentary rock layers by the formation of iron ore by the regional metamorphism, the grade of the low-scale large, Russia, North America, Brazil, Australia, and China, Liaoning, Anshan and so on, there are a large number of outputs. Magnetite is the main mineral raw material for iron refining, and is also a traditional Chinese medicine.