With water pressures of 300 atm and 1, 000 atm, vesuvianite is synthesized from glass, the composition of which is 10 CaO⋅2 MgO⋅2 AL₂O₃⋅9 SiO₂, between 400°C and 600°C. At lower temperatures the assemblage, grossularite-diopside-2 CaO⋅Si0₂nH₂O, is stable, while at higher temperatures the assemblage, melilite-wollastonite-monticellite, becomes stable.
Vesuvianite occurs rather rarely in skarn. It is found in the high temperature-zone of zoned skarn.
This experimental result and the occurrence of vesuvianite may indicate that the pyrometasomatic ore deposits were generally formed below 400°C.
Units cell dimensions of synthesized vesuvianite and of grossularite decrease with temperature. Cell dimensions of grossularite synthesized in this work are lager than those of grossularite synthesized from the composition of 3 CaO⋅AL₂O₃⋅3 SiO₂ and are smaller than those of grossularite from 3 CaO⋅AL₂O₃ 2 SiO₂.