Igneous rocks that contain many dark silicate minerals and that also are rich in magnesium and iron have a composition that is .?

Igneous rocks that are rich in dark silicate minerals and contain high levels of magnesium and iron are classified as mafic rocks. These rocks typically include basalt and gabbro, characterized by their darker color and denser composition. The term "mafic" is derived from the minerals magnesium and ferric iron, which are predominant in these types of rocks.