In other words, chemical elements are cycled and reused ... One biogeochemical cycle that is often overlooked, however, is Earth's iron (Fe) cycle (Figure 1). Numerous iron-containing minerals ...

There is a high demand for metals to be used in many kinds of industries. For example, iron (element symbol Fe) is mostly found as the minerals magnetite Fe₃O₄ and hematite Fe₂O₃.