This work is concerned about the chemical characterization of monolithic diopside-based glass ceramics (GCs). Variations from this composition were carried out through the addition of P2O5 to increase crystal density and Al2O3 to optimize the chemical properties of the GCs. The addition of MgO was sufficient for the crystallization of diopside, but additions of P2O5 made the formation of this crystalline phase difficult. The highest volume of diopside crystals was about 76% for the formulation with 5% weight of alumina. As expected, chemical resistance is directly influenced by the composition of the glass ceramic, but not so much by the fraction of crystals volume.