Abstract: Industrially crystallized potassium chloride having a potassium chloride content of at least 95 weight percent and containing a minor contaminating amount of inorganic metal salt impurities, e.g., sodium chloride, is purified by leaching compacted particles of said potassium chloride with an aqueous leaching solution, the solute of which solution is selected from the group consisting of potassium chloride and mixtures of potassium chloride and sodium chloride. The leaching solution is saturated with respect to potassium chloride and substantially unsaturated with respect to sodium chloride. The compacted particles are maintained in contact with the leaching solution for a time sufficient to reduce substantially the sodium chloride content thereof, and potassium chloride particles of reduced sodium chloride content are recovered from the leaching solution. The leached compacted particles are transparent and comprise single and compound euhedral cubic crystals.