The importance of imperviousness

Berylloaluminosilicates having faujasite structure are described. These beryllium zeolites (Y-zeolites) can have substantially higher Al2O3/SiO2 ratios than the berylliumfree aluminosilicates of similar structure; they can be obtained hydrothermally from aqueous mixtures of the components and can be used instead of the faujasites in industrial processes involving absorption or catalysts.