What is Magnetite?

Magnetite is the most common iron oxide mineral. With a chemical formula of Fe3o4, it has the highest amount of iron of  all minerals. Magnetite is also attrachted to magnets, and can become a permanent magnet itself. Magnetite has a spinel crystal structure, which crystallizes in the cubic crystal system.

Magnetite is dark gray or black in color, and a black streak color. It has a hardness of 5.5-6.5 on the mohs hardness scale. With a metgallic(shiny) luster, magnetite can also have a brownish tint in the reflection of the sun.

Where is Magnetite Found?

Magnetite is a common mineral, and can be found in all three types of rock: sedimentary, metamorphic, and igneous. Magnetite is sometimes found in beach sand, and occurs in bands or strips. This makes some of the sand at some beaches appear black. The magnetite was carried there from rivers made by erosion. The force of the beach waves concentrates it into strips of black on the light sand.


Magnetite is attracted to the magnet, but can sometimes be a magnet itself. When magnetite is automagnetized into a magnet, it is called lodestone. Lodestone is usually covered with small pieces of magnetite or other magnetic material that it attracted to itself.

Lodestone was what humans discovered magnetism from. In China, it was used as the first compasses. The lodestone would be suspended on a string, and would align itself with the Earth’s magnetic field.

Magnetite in the Human Brain

There is evidence that proves the existence of magnetite in the human brain, however only some of the magnetite in the brain occurred there naturally. Most of the magnetite was absorbed by airborne pollution. Scientists are still trying to figure out the role of the magnetite, but some theories suggest it was placed there to be used as a compass in our head.

Uses of Magnetite

Magnetite has many uses to us. Listed below are a few of the common uses of magnetite.

Magnetite, hematite, and chert are all part of taconite, the rock in which iron ore is most commonly mined. The ore from taconite is uses to produce iron or steel. Magnetite is also used as a toner in electrophotography, a pigment in some paints, and an ingredient in high-density concrete. Magnetite powder was also used for audio recording using a magnetite tape.