The rate of Al/Si disorder in “dry” low albite is greatly enhanced at high pressures. This enhancement takes place in a P-T regime where the presence of water would induce melting; none was observed. The experimental work was carried out in piston-cylinder apparatus using NaCl pressure medium. Modification of the experimental conditions to avoid production of hydrogen by dissociation of moisture in the pressure medium, as well as to capture hydrogen with Fe 2O 3 and ZnO indicates that hydrogen is the active agent in promoting Al/Si diffusion at high pressures in NaAlSi 3O 8. A mechanism involving transient OH groups that stimulate coordinations greater than 4, simultaneously breaking Al O and Si O network bonds is proposed.