| 释义 |
刚玉gāngyù矿物,成分是三氧化二铝,晶体,有玻璃光泽,硬度仅次于金刚石。红色透明的叫红宝石,蓝色透明的叫蓝宝石,是贵重的装饰品。刚玉可用作精密仪器的轴承,也用作研磨材料。{corundum; very hard mineral (Al?O?) that consists of aluminum oxide of a hardness second only to diamond, occurring in massive and variously coloured crystal form, including ruby of red colour and sapphire of blue colour (both being precious stone), that may be used as an abrasive or as a material for making bearings for precision apparatuses} |