LAGP glass-ceramics can be obtained starting from an amorphous glass with nominal composition of , which is subsequently annealed to promote crystallization. Compared to solid-state sintering, ceramic melt-quenching followed by crystallization is a simpler and more flexible process which leads to a denser and more homogeneous microstructure.
The starting point for glass crystallization is the synthesis of the glass through a melt-quenching process of precursors in suitable amount to achieve the desired stoichiometry. Different precursors can be used, especially to provide phosphorus to the material. One possible route is the following:
* Preheating of AlO and GeO at 1000 °C for 1 hour; 
* Drying of LiCO at 300 °C for 3 hours; 
* Mixing of the starting precursors in proper amounts to match the nominal stoichiometry; 
* Removal of volatile species by stepwise heating of the mix to 500 °C;
* Melting at 1450 °C for 1 hour; 
* Quenching of the melt; 
* Annealing of glass samples in air.
The main steps are summarized in the following equation:
The annealing temperature is selected to promote the full crystallization and avoiding the formation of detrimental secondary phases, pores, and cracks. Various temperatures are reported in different literature sources; however, crystallization does not usually start below 550-600 °C, while temperatures larger than 850 °C cause the extensive formation of impurity phases.