Namely, the formation of large cores of double salts: syngenite (K2SO4⋅CaSO4⋅H2O) and glauberite (Na2SO4⋅CaSO4),
in the presence of the accelerators K2SO4and Na2SO4, respectively, was due to the rapid and complete crystallization of the dihydrate (CaSO4⋅2H2O).