Here's why:

* Iron is a common element in the Earth's mantle. Igneous rocks are formed from the cooling and solidification of molten rock (magma or lava), which originates from the mantle.

* Iron can be present in various forms. It can be found as:

* Iron oxides: Commonly found in igneous rocks, giving them a reddish or brownish color (like in hematite).

* Iron sulfides: Found in some igneous rocks, contributing to their dark color.

* Iron silicates: Present in many igneous minerals like olivine and pyroxene.

Examples of igneous rocks with high iron content:

* Basalt: A dark, fine-grained volcanic rock rich in iron and magnesium.

* Gabbro: A dark, coarse-grained intrusive rock with high iron content.

* Andesite: A medium-grained volcanic rock that can contain significant amounts of iron.

Note: Not all igneous rocks are high in iron. Rocks like rhyolite and granite, which are richer in silica, typically have lower iron content.