Near-infrared chemiluminescent emission from NeMu*, the analogue of the Rydberg molecule NeH, has been observed in Ne, Ar, and Ne/Ar gas mixtures. Three temporally distinct features were observed: First, a large sharp emission peak at time zero, observed in all gases (Ne, He, N2, Ar), is assigned to scintillation light during muon thermalization, probably caused by spur electrons. Second, a low-intensity broad region observed in all gases is attributed to e+ from muon decay. Finally, NeMu in 1-6 atm Ne with 0.1-2 torr Ar appeared as a high intensity delayed emission, whose width and intensity depended linearly on the Ar concentration. Its wavelength spectrum from 680-960 nm was measured. Although questions remain as to how NeMu* is formed, the precursor is likely Nemu+. Possible electron donors include metastable Ar* (P-3(2) or P-3(0)) and long-lived free (spur) electrons.