柯林斯詞典opal /???p?l/ (opals) 1. N-VAR An opal is a precious stone. Opals are colourless or white, but other colours are reflected in them. 蛋白石 返回 opal劍橋詞典a precious stone whose colour changes when the position of the person looking at it changes 蛋白石，貓眼石 返回 opal