Charging of muscovite mica in the timeframe of order minutes, when immersed in aqueous solutions, was observed experimentally with the aid of a rotating disk system for zeta potential measurement. The mica was cleaved in air and quickly submerged in aqueous solutions of alkali metal salts. The zeta potential was measured as soon thereafter as possible. The time delay between cleaving and the first measurement was as low as 20 seconds with subsequent measurements being taken at intervals of similar duration. For example, mica immersed in 1 mM KCl at pH 5.8, adopted a zeta potential that was essentially constant within this time frame at -80 mV. When the mica was submerged in 1 mM NaCl at a similar pH, however, the first measured zeta potential was -120 mV and rose to a steady value at -95 mV with a transition time of order 1000 s. The transition behavior depended on pH. At pH 5 the zeta potential approached its steady value from more negative potentials. At pH 4 the zeta potential approached its steady value from more positive potentials. Transient behavior was observed in KCl solutions of concentration less than 1 mM, and at all concentrations of NaCl. These results are discussed in the context of a dynamic single site binding model that tracks the surface coverage of potassium, sodium, and hydrogen ions. Appropriate choices of dissociation and association rate constants allow fitting of the dynamic response of the mica to the model.