It is more difficult to distinguish cases where magnetite is mixed with … Lodestones were used as an early form of magnetic compass. This technique employed the difference in densities between coal (1.3–1.4 tonnes per m³) and shales (2.2–2.4 tonnes per m³). Hydrothermal synthesis usually produce single octahedral crystals which can be as large as 10mm across. In Tasmania there are many areas with highly magnetized rocks that can greatly influence compasses. Ferrofluids can be used for targeted drug delivery in the human body. Heavy concrete is widely used in buildings that require protection from radiation, such as nuclear power plants, X-ray facilities and uranium mining sites. What is Hematite? Magnetite is a type of iron oxide with natural magnetic properties. Magnetite is important widely due to its magnetic properties. Naturally-magnetized pieces of magnetite, called lodestone, will attract small pieces of iron, which is how ancient peoples first discovered the property of magnetism. Extra steps and repeated observations are required when using a compass in Tasmania to keep navigation problems to the minimum. In one study, the characteristic nanoparticles were found in the brains of 37 people: 29 of these, aged 3 to 85, had lived and died in Mexico City, a significant air pollution hotspot. Festival of Sacrifice: The Past and Present of the Islamic Holiday of Eid al-Adha. , Magnetite can also be found in fossils due to biomineralization and are referred to as magnetofossils. Small amounts of magnetite are also used as a toner in electrophotography, as a micronutrient in fertilizers, as a pigment in paints, and as an aggregate in high-density concrete. Today it is mined as iron ore. Small grains of magnetite occur in almost all igneous and metamorphic rocks. Optical studies show that this metal to insulator transition is sharp and occurs around 120 K. The Verwey transition is dependent on grain size, domain state, pressure, and the iron-oxygen stoichiometry.  Huntington patients have not shown increased magnetite levels; however, high levels have been found in study mice.. The dark, glossy nature of magnetite ore has led to its use in landscaping as accent rocks. The dune field covers 250 square kilometers (100 sq mi), with the highest dune at over 2,000 meters (6,560 ft) above the desert floor. It is also used in coal mining operations as a slurry with water to remove the heavier impurities by allowing the less dense coal to float to the surface. Compositions of the mineral pairs are used to calculate how oxidizing was the magma (i.e., the oxygen fugacity of the magma): a range of oxidizing conditions are found in magmas and the oxidation state helps to determine how the magmas might evolve by fractional crystallization. One use of magnetic tape that still exists is tape vaulting for the storage of physical records. When magnetite is added to a concrete mix, it produces heavy concrete, which is twice as dense as standard concrete. This would allow the treatment of only a small area of the body, rather than the body as a whole, and could be highly useful in cancer treatment, among other things. As a member of the spinel group, magnetite can form solid solutions with similarly structured minerals, including ulvospinel (Fe2TiO4), hercynite (FeAl2O4) and chromite (FeCr2O4). Ferric chloride and ferric sulphate are manufactured with magnetite as one of the starting materials. These chemicals are effective in clarifying raw water in water purification plants. , The chemical composition of magnetite is Fe2+Fe23+O42−.  In some brain samples, the nanoparticle pollution outnumbers the natural particles by as much as 100:1, and such pollution-borne magnetite particles may be linked to abnormal neural deterioration. [dubious – discuss] Biological magnetite may store information about the magnetic fields the organism was exposed to, potentially allowing scientists to learn about the migration of the organism or about changes in the Earth's magnetic field over time. , Octahedral crystals of magnetite up to 1.8 cm across, on cream colored feldspar crystals, locality: Cerro Huañaquino, Potosí Department, Bolivia, Magnetite with super-sharp crystals, with epitaxial elevations on their faces, Alpine-quality magnetite in contrasting chalcopyrite matrix.