Available data of density, molar volume, refractive index and molar refraction of Al2O3–SiO2 glasses have been analyzed. The analysis shows that any of these properties can be expressed in terms of a factor of SiO4 tetrahedron and another one related to a structural species of AlO3/2 formula. These factors, together with previously found factors of the modified AlO4 tetrahedra, are useful to calculate the properties of Li2O–Al2O3–SiO2 and CaO–Al2O3–SiO2 glasses with [Al2O3/(Li2O or CaO)]>1. Structural forms of AlO4, AlO5 and AlO6 groupings are proposed, in which the charge compensation is attained through various distributions of 2-, 3- and 4- coordinated O2– ions. Any of these groupings is equivalent to the AlO3/2 formula. It is concluded that the studied properties are not sensitive to coordination of Al3+ ions.