Anthophyllite-hornblende-almandite form reaction zones in anorthosite at Grønengja, Sunnfjord, West Norway. Anthophyllite may have formed from orthopyroxene by constant-volume reaction, and the reaction zones appear to be the almandite amphibolite facies equivalent of the orthopyroxeneclinopyroxene- garnet reaction zones from the Bergen Are anorthosites.