變成岩 (Piàn-sêng-giâm) (變成岩; metamorphic rock)，或 (he̍k)變質岩 (piàn-chit-giâm) (變質岩)，是 (sī)經由 (keng-iû)變成 (piàn-sêng)作用 (chok-iōng)所 (só͘)形成 (hêng-sêng)的 (ê)岩石 (gâm-chio̍h)。原底 (Goân-té)的岩石 (會當 (ē-tàng)是堆積岩 (tui-chek-giâm)，火成岩 (hóe-sêng-giâm)頁 (ia̍h)變成岩) 受著 (siū-tio̍h)熱 (jia̍t)佮 (kap)壓力 (ap-le̍k)的作用，伊 (i)內部 (lōe-pō͘)的物理 (bu̍t-lí)佮化學 (hoà-ha̍k)性質 (sèng-chit)漸漸 (chiām-chiām)變化 (piàn-hoà)。一寡 (Chi̍t-koá)卡 (khah)捷看 (chia̍p-khoàⁿ)的變成岩有 (ū)片麻岩 (phiàn-bâ-giâm)，檐板岩 (liâm-pán-giâm)，大理石 (tāi-lí-chio̍h)，結晶 (kiat-cheng)片岩 (phiàn-giâm)佮石英 (chio̍h-eng)。
