corundum

名词 corundum:

1. very hard mineral used as an abrasive
   同义词：corundom

co.run.dum

n.（名词）
An extremely hard mineral, aluminum oxide, Al2O 3, sometimes containing iron, magnesia, or silica, that occurs in gem varieties such as ruby and sapphire and in a common black, brown, or blue form used chiefly in abrasives.
刚玉：一种极为坚硬的矿物，氧化铝，Al2O 3，有时含铁、氧化镁或硅土，存在于各种宝石中，如红宝石、蓝宝石，并且在磨蚀剂中以普通的黑色、棕色或蓝色形式出现

来源：
Tamil kuruntam
泰米尔语 kuruntam