Magnetite (noun)

A black, magnetic mineral, iron oxide, Fe3O4, found in the earth's crust and used as an iron ore.

Origin:

Late 18th century, from magnet + -ite.

Examples:

1. Magnetite is a common iron ore mineral.
2. Magnetite is a mineral that is naturally magnetic.
3. Magnetite can be found in a variety of geological environments.
4. Magnetite is a very hard mineral.
5. Magnetite is used to produce iron and steel products.