Thermal Analysis Curves of Silicate Minerals

Silicate minerals undergo dehydration, decomposition, polymorphic transformation, recrystallization of the dehydrated substances, melting and valence-state change of variable-valence elements. 

Fayalite—865 X exotherm, fayalite decomposes and Fe oxidizes to Fe accompanied by a mass increase 1321X exotherm, the decomposed and oxidized substance converts to hematite and cristobalite. 

Tephroite—From 700 °C, Mn oxidizes, accompanied by a mass increase. 

Chrysolite—1250 °C endotherm, part of chrysolite decomposes to hematite and enstatite [(Mgfl Fe , )2Si20(,] 1393 °C endotherm, part of chrysolite decomposes to magnesioferrite (MgFejO ), fayalite and enstatite at a temperature higher than 800 °C, the Fe oxidizes accompanied by a mass increase. 

---