5. (3) reaction rim or retrograde rim, e. g., omphacite with diopside rim, diopside with amphibole rim, and ilmenite rim of rutile.

• (3)反应边或退变边,如绿辉石的透辉石退变边、透辉石的角闪石退变边和金红石的钛铁矿退变边等。