One of the major classifications used for igneous rocks is based on where in the Earth the partial melts or magmas crystallize to form igneous rocks.
(the major classifications; used; for igneous rocks) (One of the major classifications; is based; on where in the Earth the partial melts or magmas crystallize to form igneous rocks) (the partial melts or magmas; crystallize; to form igneous rocks)
the major classifications One of the major classifications the partial melts or magmas
used is based crystallize
for igneous rocks
on where in the Earth the partial melts or magmas crystallize to form igneous rocks
to form igneous rocks