The dark colored igneous rock rich in iron and magnesium is called mafic.

Here's a breakdown:

* Mafic rocks are a type of igneous rock characterized by their high content of magnesium and iron, giving them a dark color.

* They are typically found in oceanic crust and are formed from the cooling of magma that originates from the Earth's mantle.

* Common examples of mafic rocks include basalt, gabbro, and pyroxenite.

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