Processes of concentration of potassium salts probably begin after first precipitation of salt within an evaporite basin. As brine is concentrated, very complex solutions are formed which influence chemical and physical factors of concentration. Environmental and geologic processes further restrict locations for precipitation of potash. Upon complete evaporation of seawater and burial of salts, potash salts may be concentrated further and enriched by metasomatic processes. Salts now are precipitating on a reduced scale in limited areas along continental margins, inland seas, continental brine lakes, and salt pans. Trace minerals furnish much information on the genetic character. Argon, common where high concentration of potassium is present, can be used to determine the age of the salt.