Alumina-rich mixtures of La2O3 and Al2O3 have equilibrium phases that are perovskite (LaAlO3) and beta-alumina (LaAl11O18). Annealing initially glassy samples with compositions 3La(2)O(3)-5Al(2)O(3) or 11La(2)O(3)-14Al(2)O(3) between 860degrees and 1075degreesC creates a metastable state that is clearly detected by Xray diffraction (XRD). While structures have not been determined, the new state appears to have two crystalline phases. This metastable state is favored by low annealing temperatures and by compositions with more rare-earth oxide. Similar behavior is seen with Nd2O3:Al2O3 compositions, although the smaller Nd ion is less effective in promoting the metastable structure. The detection of equilibrium P-alumina by XRD can be difficult, leading to possible misinterpretation of phases that are present.