Chart 1b. IUGS diagram for naming plutonic/phaneritic igneous rocks with An>50. This QAPF diagram is two independent ternary diagrams that share the A-P edge. The upper triangle has the corners A-Q-P, where A is Alkali feldspar, Q is Quartz, and P is Plagioclase. The lower triangle has the corners A-P-F, where A is Alkali feldspar, P is Plagioclase, and F is Foid (meaning any feldspathoid mineral). Numbers on horizontal lines on the chart are ternary modal (=volume) percentage (Q relative to A+Q+P or F relative to A+P+F). Numbers on inclined or vertical lines are binary modal percentage (P relative to A+P).

For plutonic rocks with An<50% click here: IUGS Plutonic QAPF
For only quartz-bearing plutonic/phaneritic rocks click here: IUGS Plutonic QAP
For only foid-bearing plutonic/phaneritic rocks click here: IUGS Plutonic FAP