Question

In general how does the characteristic mineral composition of a light colored igneous rock differ from that of a dark colored rock

Answer 1

Light colored igneous rock is called felsic, it  is high in quartz, muscovite mica, and orthoclase feldspar content.  Dark colored igneous rock is called mafic, and contains a lesser amount of silica along with olivine, pyroxene, amphibole, biotite mica, and plagioclase feldspa

Light coloured igneous rocks (felsic) tend to have greater silica and aluminum content and a lower iron and magnesium content than dark (mafic) rocks.