0 72na 2 o al 2 o 3 70 5sio 2 the procedure of example 1 was repeated wherein the formulation of solution d was changed as follows in this way 58 1 grams of crystalline aluminosilicate isi 6 of 85 purity was obtained it contained 15 of an impurity crystalline silicate of different crystal structure the composition of the aluminosilicate as determined in the same manner as in example 1 was 1 01na 2 o al 2 o 3 68 0sio 2 the procedure of example 1 was repeated wherein the formulation of solution d was changed as follows in this way 57 5 grams of crystalline aluminosilicate isi 6 of 100 purity was obtained the composition of the aluminosilicate as determined in the same manner as in example 1 was 0 33na 2 o al 2 o 3 72 1sio 2 the procedure of example 1 was repeated wherein the formulation of solution a was changed as follows ______________________________________aluminum sulfate 18 hydrate 33 8 gramsconcentrated sulfuric acid 97 2 0 gramswater 100 milliliters______________________________________ in this way 65 5 grams of crystalline aluminosilicate isi 6 of 100 purity was obtained the composition of the aluminosilicate as determined in the same manner as in example 1 was 0.