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

• 一种轻而韧的金属元素，有光泽、抗腐蚀，用于韧而轻的合金（如飞机部件）中，主要来自金红石和钛铁矿。收藏指正