A process for fabricating a crystalline scintillator material with an elpasolite structure that has a theoretical composition of A2BC(1-y)MyX(6-y) can include conducting crystallization by cooling from a melt bath including r moles of A and s moles of B. A is chosen from Cs, Rb, K, and Na. B is chosen from Li, K, and Na. C is chosen from athe rare earth elements, Al, and Ga. M is chosen from the alkaline earth elements. X is chosen from F, Cl, Br, and I, and y represents the atomic fraction of substitution of C by M and is in the range extending from 0 to 0.05. The melt bath can be in contact with the material containing A and B in such a way that 2s/r is above 1. The process shows an improved fabrication yield. The crystals formed therefrom can have improved scintillation properties.