 Gyrolite can be synthesized in the laboratory, or industrially, by hydrothermal reaction in the temperature range 150 – 250 °C by reacting CaO and amorphous SiO2, or quartz, in saturated steam in the presence of CaSO4 salts or not.At temperature lower than 150 °C, the reaction rate is very slow.At temperature above 250 °C, gyrolite recrystallizes into 1.13 nm tobermorite and xonotlite.