The Behavior of Water in Orthoclase Crystal and Its Implications for Feldspar Alteration

The phenomenon of feldspar alteration that occurs in the interior crystals remains poorly understood. We observed experimentally water can go into orthoclase under pressures up to 600 MPa at room temperature. With increasing pressure, FTIR spectra colorless show a sharp increase integral absorbance from 1.50 cm−1 14.54 and normalized 120 cm−2 1570 cm−2; pink saturates quickly with no significant change either or absorbance. different responses pressure between might be related K content structure. Moreover, atmospheric collected crystallography directions intensities, which illustrates characteristic preferred crystallographic orientations. These results reveal H2O molecules occur as structural constituents entering channels alkali crystals, preferentially along (001) orientation. findings provide clues mechanism occurring well formation micropores microstructure minerals. This study also provides important insights behavior nominally anhydrous minerals upper crust Earth.