A lamp includes a discharge sustaining fill which includes cesium halide,
one of indium halide and thallium halide, optionally gadolinium halide
and a rare earth halide component selected from dysprosium halide,
holmium halide, thulium halide, and neodymium halide. In operation
without a jacket, the lamp may have a color temperature of from 7,000K to
14,000K and a color rendering index of at least 70 when operated at an
arc wall loading in excess of about 2 W/mm.sup.2.