A metal halide lamp (10) includes a discharge vessel (12) which may be
formed of a ceramic material. The vessel defines an interior space (16).
An ionizable fill is disposed in the interior space. The ionizable fill
includes an inert gas and a halide component. The halide component
includes a sodium halide, a cerium halide, at least one of a thallium
halide and an indium halide, and optionally a cesium halide. The cerium
halide is at least about 9 mol % of the halide component. At least one
electrode (18, 20) is positioned within the discharge vessel so as to
energize the fill when an electric current is applied thereto.