The eight most common elements in earth's crust are: o, si, al, fe, ca, na, k, and mg. these elements account for 98% of the atoms in earth's crust. these eight elements combine chemically with one another to make six main minerals which account for 90% of the minerals in earth's crust. these minerals, the so-called the rock forming minerals, are: feldspar, pyroxene, amphibole, mica and the last, made up of the two most abundant elements, is