Muscovite 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 with the aid of an apparatus based on detection of streaming potential in the vicinity of a rotating disk. The time between cleaving the sample and immersion was less than one minute and the elapsed time before the first measurement after immersion was as low as 20 seconds with subsequent measurements being taken at intervals of similar duration. When mica was immersed in 1 mM KCl at pH 5.8, the mica 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 a decay to a steady value at -95 mV was observed with a decay time of order 1000 s. When freshly cleaved mica was immersed in solutions at lower pH, a maximum appeared in the zeta potential and the transition time was reduced. 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.