Lu3Al5O12:Ce 3+ is a promising color converter for laser diode-(LD-) driven solidstate lighting and displays due to the improved thermal stability of its luminescence compared to widely-used Y3Al5O12:Ce 3+ materials. However, LuAG:Ce 3+ emits green light, which is a severe drawback for white lighting applications. Here, we report new biphasic Lu3MgAl3SiO12:Ce 3+ (BP-LMAS:Ce 3+) transparent ceramics that exhibit redshifted emission via the inclusion of a secondary phase (Lu/Mg)4(Al/Si)2O9. This phase, dispersed homogeneously in the BP-LMAS:Ce 3+ matrix, provides scattering centers which improve the uniformity of the emitted light. The material demonstrates a broad orange-yellow emission band centered at 564 nm (450 nm excitation), internal quantum efficiency of 76.1% and transmittance of 76%, and enhanced thermal stability. Under excitation of 14.5 W mm-2 blue LDs, it generates white light with a high luminous flux of 5655 lm. This demonstrates that BP-LMAS:Ce 3+ transparent ceramics are promising candidates as color conversion materials for LD-driven white lighting applications.