Following our researches on the transformation of synthetic glasses of the SiO₂-Al₂O₃-CaO ternary system, when baked at ordinary temperature with saturated lime solution, the Authors have studied the behaviour of some glasses rich in alumina and in lime, with the purpose of extending the investigations about the effects of the chemical composition on the nature of the newly formed products. With reference to the alumina bearing hydrated phases, it has been pointed out that the formation, at ordinary temperature, of members of grossularite-tricalcium aluminate hexahydrate series (hydrogarnets), requires compositions rich in alumina and in lime. It has been besides emphasized that for proper alumina (and silica) amount, hydrogarnets formation is promoted by the lime content of the starting glass, or by lime increase through fixation from the saturated solution. It has been moreover indicated that, at ordinary temperature, glasses of proper composition give rise to members of the hydrogarnets series by simple treatment with water. It has been after all shown that, within the limits of the examined compositions, the increase of silica in the starting glass promotes the formation of gehlenite hydrate, which, in the presence of lime, is unstable at ordinary temperature, too, and changes into members of hydrogarnets series solid solutions.