52 A Hard and Beautiful Mineral

What is the world’s hardest natural substance? If you guessed something like iron or marble, you would be wrong. The world’s hardest substance is actually the diamond. Diamonds are formed deep in the earth and hardened by the intense heat and pressure found there. That pressure pushes the diamond material up near the surface into outlets called pipes. There the material cools off, and from there diamonds can be mined. To bring out a diamond’s brilliance, the stone must be cut and polished. The most valuable diamonds are clear—there are no dull spots in them. They are also colorless. (A few diamonds are pink or some other color, but these are rare and very expensive.) Valuable diamonds are fairly large, at the very least one carat in weight. And they are also well cut. This means they have even-sided faces, or facets, that reflect light clearly and evenly. If diamonds are so hard, what is used to cut them? You guessed it: other diamonds. Many factories also use diamonds to cut other hard substances. Diamonds are used in polishing as well. Polishing material made of diamond particles can be used like sandpaper. It can make steel surfaces so smooth that they reflect like fine mirrors. The world has always valued diamonds. People have fought over them, and curses have been placed on them. They are a symbol of power as well as love. 52 一种坚硬且美丽的矿物 世界上最坚硬的天然物质是什么？如果你猜是铁或大理石之类的东西，那你就错了。世界上最坚硬的物质实际上是钻石。 钻石形成于地球深处，在那里的高温高压作用下硬化。这种压力将钻石原料推到地表附近的被称为 “岩管” 的出口中。原料在那里冷却，之后钻石就可以被开采了。 要展现钻石的璀璨光芒，必须对其进行切割和抛光。最珍贵的钻石是纯净的 —— 它们内部没有黯淡的斑点，同时也是无色的。（少数钻石是粉色或其他颜色，但这些钻石很稀有且价格昂贵。）珍贵的钻石体积相当大，重量至少有一克拉。而且它们的切割工艺也很好，这意味着它们拥有边缘均匀的面（即刻面），能够清晰且均匀地反射光线。 既然钻石如此坚硬，用什么来切割它们呢？你猜对了：用其他钻石。许多工厂也用钻石来切割其他坚硬的物质。钻石还被用于抛光 —— 由钻石颗粒制成的抛光材料可以像砂纸一样使用，能让钢铁表面变得极为光滑，光滑到可以像优质镜子一样反射光线。 世界一直很珍视钻石。人们曾为钻石争斗，钻石也被附上过诅咒。它们既是权力的象征，也是爱情的象征。