Fo
Liquid
En
SiO2 
X
Forsterite + Enstatite
Enstatite + Silica
Enstatite + Liquid
Forsterite + Liquid
Text Box: Temperature
Temperature
P = 1 atm
1. Cool liquid X to liquidus;
2. Liquid changes composition as En is removed; liquid cools to eutectic, E; silica crystallizes.
3. Temperature remains constant until liquid is completely crystallized
4. Crystalline En + silica cool
P
E
En begins to crystallize