Collection: Magnetite

Magnetite is a mineral species composed of iron(II,III) oxide, with the formula Fe3O4 (sometimes written FeO·Fe2O3), with traces of magnesium Mg, zinc Zn, manganese Mn, nickel Ni, chromium Cr, titanium Ti, vanadium V and aluminum Al. Magnetite is a ferrimagnetic material.

Titanium-rich varieties are called titaniferous magnetites, or more often titanomagnetites.

Magnetite crystals can be biomineralized, that is, biosynthesized by certain living species4, which seem to be able to use them to orient themselves in space.

Magnetite has been known since at least the Iron Age; the first written mention dates from Pliny the Elder in 77; it was described by Wilhelm Karl Ritter von Haidinger in 1845; its name derives from the German Magnetit, a word itself derived from the Latin magnes, magnetis meaning magnet and ultimately deriving from the name of the province of Magnesia, rich in magnetite.

It forms typically octahedral crystals, more rarely dodecahedral, exceptionally cubic, which can reach almost 25 cm9.

At a temperature of 580 °C (Curie point), magnetism disappears and then reappears when it cools. The remanence is of the order of 480 Gauss. This mineral is an electrical conductor.
It is part of the spinel group.
It gathers species of similar structure. There are more than 20 species.
The generic formula is XY2O4 where X represents a divalent metal (magnesium, iron, nickel, manganese and/or zinc) and Y a trivalent metal (aluminum, iron, chromium and/or manganese, titanium).