Pressure and temperature are basic thermodynamic variables transforming matter from one state to another. Our knowledge of pressure-induced phase transformations of zeolites, however, is very limited compared to the vast number of temperature-dependent studies performed over the past several decades. 1-3 This is partly due to the required experimental complexities as well as the analytical ambiguities arising from the porous nature of the materials, which can lead to compositional changes upon interaction with various pressure-transmitting media. 4-6