The sign of the surface charge for alkali halides in their saturated brines has been established from nonequilibrium electrophoresis measurements, and on this basis the flotation response of alkali halides was explained based on the adsorption of oppositely charged collector colloids by heterocoagulation. These surface charge results for alkali halides are generally as expected from simplified lattice ion hydration theory with some exceptions, specifically LiF, KCl, NaCl, KBr, RbBr, KI, and RbI. The presence of natural oxygen defect states in the crystal lattice and the inaccuracies involved in the gaseous ion hydration free energy values used appear, in the past, to be responsible for these deviations. The presence of natural oxygen defect states in KCI, KBr, RbBr, and RbI, as characterized by UV/Vis absorption, was found to account for their anomalous surface charge. Further, other positively charged alkali halides, LiF, NaCl, and KI, were found to be free of oxygen defect states. Nevertheless, oxygen defects can be created in these alkali halides to make them negatively charged, and this has been demonstrated for NaCl. Such negatively charged NaCl can be readily floated with positively charged amine collector colloids, thus confirming the surface charge/collector colloid adsorption theory.