n.any of various minerals consisting of hydrous silicates of aluminum or potassium etc. that crystallize in forms that allow perfect cleavage into very thin leaves
○ used as dielectrics because of their resistance to electricity
例句
1.
A Oeiger counter senses ionizing radiation by means of a GM (Geiger Mueller) tube. Some tubes have a thin mica window. 盖革计数器借助盖革米勒(Geiger Mueller)管检测电离辐射。有些管有一块薄的云母窗。
2.
SO the dark mica in this granite should be called biotite. 那么．在这块花岗岩中的黑色云母类矿物就应当叫做黑云母了。
3.
Now, use your pocketknife to touch the mica and see what will happen. 现在你用小刀去触及岩石中的云母，看看会产生什么现象。
词汇听力：
小测验：选择正确的单词