Figure 7.06. Ab-Or TX Diagram. The liquidus and solidus for the alkali feldspar solid solution meet at an azeotrope minimum. This relationship is typical for minerals that have a solvus at lower temperatures. The alkali feldspar melting diagram is complicated by the incongruent melting of K-rich compositions to leucite (Lct) and liquid, neither of which plot on the Ab-Or binary and have been removed. To see the Lct field click the "Show Lct" button. This diagram is based on the experimental work of Schairer (1950) and Tuttle and Bowen (1958).
Wt.% KAlSi3O8:
Temperature: °C
Temperature: °C
