Quantitative phase analysis (QPA) applied to the PXRD pattern at 118 °C gave a phase mixture of 94.3(1.2) wt% HT phase+5.7(2) wt% pharmacoalumite. This compares with a phase composition of 97.8(7) wt% liskeardite+2.2(1) wt% pharmacoalumite prior to the transition (78 °C). There Tolvaptan more than a doubling of the amount of pharmacoalumite impurity phase in the product heated to 118 °C. Using the pharmacoalumite as an internal standard and scaling to the 78 °C QPA result indicates that the product at 118 °C contains at least 50% of amorphous material. This conclusion was supported by ex situ PXRD studies. A sample that was heated to 100 °C to transform the liskeardite to the HT phase and then rehydrated to reform liskeardite displayed a 50% reduction in the intensities of the liskeardite peaks. The loss of crystallinity is most likely due to disruption of the framework as strain builds at the tetrahedral linkages due to their diametrically opposed hinges.