All of the andesites
contain small to negligible amounts of mafic xenocrysts
derived from the upper mantle and lower
crust. The mafic phenocrysts can be distinguished
from xenocrysts by their crystal outline: the former
are euhedral and smaller in size, while the latter are
irregular,broken and homogeneous No. phenocrystic
or groundmass orthopyroxenes have been identified
in any basalts and andesites.