MgO / Fe2O3(T)
The ratio of magnesium to iron does
not vary greatly among most kinds of stony meteorites. Rocks
with MgO/Fe2O3(T) <0.2 or >6
are not probably meteorites. Only rare lunar granites have
low MgO/Fe2O3(T), and none of these
has been found as a lunar meteorite.
See Notes, Caveats, and References