The character of kaolinite hydromicatization within the Donetsk Basin tonsteins in the course of metamorphism depends on the types of enclosing coals: either normal or salty ones. Alongside with terrigenous minerals within the coal-bearing masses and the fossil sea waters, indicator authigenous minerals from salty coals – halite and glauberite – should be specified as the sources of sodium and potassium for kaolinite hydromicatization.