Here's how it works:

* Mafic Minerals: Minerals like pyroxene and olivine are rich in iron and magnesium, giving the rocks a dark color (think black, dark green, or brown). These rocks are called mafic rocks.

* Felsic Minerals: Minerals like quartz and feldspar are rich in silica and aluminum, resulting in lighter colors (like white, gray, or pink). These rocks are called felsic rocks.

The relative amounts of mafic and felsic minerals influence the overall color of the igneous rock.

* High mafic content: Leads to darker rocks (like basalt and gabbro).

* High felsic content: Leads to lighter rocks (like granite and rhyolite).

It's important to note that other factors can also contribute to the color of igneous rocks, including:

* Weathering: Over time, weathering can change the color of igneous rocks.

* Presence of other minerals: Small amounts of other minerals, such as iron oxides, can also influence color.

But the primary factor determining the color of igneous rocks is the mineral composition.