A steam injector assembly for handling steam in a subterranean well includes a steam separation system, the steam separation system directing an initial high quality steam to a subterranean formation and directing low quality fluid mix to a heating system. The heating system includes a ceramic-containing member located in a travel path of the low quality fluid mix and an electromagnetic antenna positioned to heat the ceramic-containing member with electromagnetic waves. A relief valve is movable to an open position when an improved high quality steam within a heating chamber of the heating system reaches an injection pressure, wherein in the open position, the relief valve provides a fluid flow path out of the heating chamber.