Gems Treasures from the Earth

Gems, Treasures from the Earth, written by Molly Chen.

宝石，来自地球的珍宝，作者：陈茉莉。

Introduction. Many people consider gems to be Earth's most beautiful creations. They are willing to spend thousands of dollars for even a small bit of that beauty.

前言 很多人认为宝石是地球最美丽的造物 哪怕只是一小块这样的美丽，人们也愿意花数千美元买下它。

There are three main types of gems. The first two, crystals and stones, are made of minerals, the natural non -living substances that make up most rocks. Crystals are minerals that form in tight shapes and neat patterns. Stones are mixed minerals that have beautiful colors and patterns, but do not have strict shapes. The third group, organic gems, are made by living things.

宝石主要分为三大类 前两类晶体和石类宝石都由矿物构成，矿物是组成大多数岩石的天然非生命物质 晶体是形状规整、结构有序的矿物 石类宝石是混合矿物，有着漂亮的颜色和纹路，但没有固定规整的形状 第三类有机宝石由生物体生成

How are gems formed? Crystals are special forms of minerals. Every mineral is made of millions of particles called atoms. In most rocks, the atoms are mixed together. But in crystals, the atoms are arranged in neat, orderly patterns. Crystals have flat sides, called faces, which form shapes.

宝石是怎样形成的呢？ 晶体是一种特殊的矿物形态 每一种矿物都由数百万个叫做原子的微粒构成 大多数岩石里，原子都是混合在一起的 但在晶体中，原子会排列成整齐有序的结构 晶体有平整的侧面，叫做晶面，它们共同构成了晶体的形状

Most crystals form deep within the Earth under very special conditions. Some, like diamonds, form when the mineral is squeezed under layers of rocks. The squeezing forces the atoms to arrange themselves in the smallest shape possible. Others, such as sapphires, form when a mineral gets so hot inside the Earth that it melts. As it slowly cools, the atoms form a regular crystal pattern. And still other gems, such as opals, form when minerals dissolve in water. As the water evaporates very slowly, the mineral left behind forms a crystal.

大多数晶体都形成于地球深处的特殊环境中 有些宝石比如钻石，是矿物被岩层挤压后形成的 挤压迫使原子排列成尽可能紧凑的形状 还有些宝石比如蓝宝石，是地球内部的矿物受热熔化后形成的 当矿物慢慢冷却，原子就会形成规则的晶体结构 还有一些宝石比如欧泊，是矿物溶解在水中后形成的 当水分慢慢蒸发，残留下来的矿物就形成了晶体

The minerals in stones do not form orderly patterns, and they may have other minerals mixed in. Stones often form in layers that make streaks and lines called the grain. Organic gems, which include pearls, amber, and coral, come from living things. Pearls begin when a grain of sand gets trapped inside an oyster shell. The oyster covers the grain with layers of the material it uses to build its shell. Coral is made of skeletons left behind by millions of tiny sea creatures. Amber began millions of years ago as tree sap.

石类宝石中的矿物不会形成规则排列，还可能混合了其他矿物 石类宝石通常形成层状结构，产生的条纹纹路叫做纹理 有机宝石包括珍珠、琥珀和珊瑚，都来自生物体 沙粒卡在牡蛎壳中时，珍珠就开始慢慢形成了 牡蛎会用建造自身外壳的物质，一层层把沙粒包裹起来 珊瑚是数百万微小海洋生物留下的骨骼堆积而成的 琥珀在数百万年前只是树木分泌的树汁