How are felsic intermediate and mafic igneous rocks different?
Felsic rocks are greater than 65% silica and contain less of the heavy elements present in mafic rocks. Felsic rocks are generally lighter in color than mafic rocks. Intermediate rocks contain between 55 and 65% silica. Mafic is a term used to describe an igneous rock that contain between 45 and 55% silica, is usually dark in color, with a chemistry that may be high in magnesium and iron.
