The discovery of new phases in a well-established phase field (Figure ) illustrates the challenges encountered in the exploration of chemical space that can affect both manual and automated experimental workflows. Because of the range of chemistries encountered in practice, an array of tools is needed to allow the deployment of workflows that match the specific chemistry under study, which can vary even within the same phase field. This is illustrated by the exploration of BaO-Y2O3-SiO2 chemical space. Ba5Y13[SiO4]8O8.5 (Phase A) was located and isolated through an iterative route that combined electron, X-ray, and neutron diffraction with chemical analysis methods. Ba3Y2[Si2O7]2 (Phase B) required in addition the introduction of a quantitative probabilistic composition prediction tool that explicitly dealt with uncertainties in the available phase assemblage information to navigate around the glass field competing with the crystalline target material. The complementary use of these exploration routes enabled the isolation of two phases in the absence of single crystals, and, by minimizing the impact of the glass-forming region, allowed investigation of a wide compositional range.