Di-An TX Diagram with Pressure Slider. Temperature-Wt.% Anorthite diagram at 1.6 GPa pressure. Diopside (Di)-Anorthite (An) two phase mixures melt at 1419°C at a eutectic melt composition that is 67 wt.% An. At higher pressures (dry) anorthite melts incongruently to corundum (Crn) + Liquid. Use the sliders to see how the melting relations change with pressure, one showing dry rocks under pressure, one showing wet rocks under pressure. Only one slider will work at a time. Click on the radio button below the one you wish to use. These diagrams are based on data from Presnell and others (1978), Goldsmith (1987), and Presnell (1995).