短文金子阅读与理解（黄金和钻石哪个更稀少）

短文金子阅读与理解（黄金和钻石哪个更稀少）另一方面，钻石是由一种非常常见的碳元素在高压下形成的形态。没有经历过高压的碳元素的形态被称为石墨，也就是我们铅笔中的东西。根据《地壳中的流体：它们在变质，构造和化学传输过程中的意义》（Elsevier Science Ltd.，1978）一书中的研究，与金相比，地壳中碳的平均密度约为十亿分之二十。这本书由著名地质学家威廉·费菲（William Fyfe）撰写，他已于2013年去世。根据费托乔克（Fedortchouk）的说法，地壳中金子的平均密度“非常非常低”，为十亿分之四。她说，如果要具备有开采价值的黄金密度，金矿的金子储量必须要高出1250倍。麻省理工学院的地球科学家兼教授乌尔里希·福尔（Ulrich Faul）说，地球上稀有元素之一的金子作为一种重金属，是在中子星碰撞过程中形成的。加拿大新斯科舍省哈利法克斯的达尔豪西大学地球科学教授兼实验高压地质研究实验室副主任亚娜·费托乔克（Yan

黄金和钻石哪个更稀少？

翻译：涂博士

钻石代表着永恒，黄金代表着珍贵，两个都是好东西，但哪个更稀有呢？稀缺度与我们在珠宝店看到的价格有关系吗？

事实证明，答案并不像你可能想象的那样“清晰”。

麻省理工学院的地球科学家兼教授乌尔里希·福尔（Ulrich Faul）说，地球上稀有元素之一的金子作为一种重金属，是在中子星碰撞过程中形成的。

加拿大新斯科舍省哈利法克斯的达尔豪西大学地球科学教授兼实验高压地质研究实验室副主任亚娜·费托乔克（Yana Fedortchouk）说，在地球形成过程中，由于万有引力的作用，最重的元素被吸引到了地球的核心，这也意味着在地壳附近很难找到大量的黄金。

虽然密度很低，但你还是可以在地表上找到金子。 费托乔克（Fedortchouk）告诉《Live Science》，金子存在于地壳中各种各样的岩石中。 “但是要形成矿床，金子的含量必须达到一定的密度才有开采价值。”

根据费托乔克（Fedortchouk）的说法，地壳中金子的平均密度“非常非常低”，为十亿分之四。她说，如果要具备有开采价值的黄金密度，金矿的金子储量必须要高出1250倍。

另一方面，钻石是由一种非常常见的碳元素在高压下形成的形态。没有经历过高压的碳元素的形态被称为石墨，也就是我们铅笔中的东西。根据《地壳中的流体：它们在变质，构造和化学传输过程中的意义》（Elsevier Science Ltd.，1978）一书中的研究，与金相比，地壳中碳的平均密度约为十亿分之二十。这本书由著名地质学家威廉·费菲（William Fyfe）撰写，他已于2013年去世。

因此，钻石的稀有性与其元素组成无关。不过，大自然将碳转化为可开采的钻石矿床的过程是一个极其艰巨而且极少成功的过程。

费托乔克（Fedortchouk）说：“钻石只能在地幔（地幔是地壳下面的地球层。）中产生，并以某种方式被带到地表。另外陨石撞击时也会形成钻石，但这些钻石很小，成不了宝石，没有什么价值。在地球地幔深处形成的钻石可以由深部岩浆带到地表，也可以是在造山过程中随着深层岩石的缓慢抬升过程中被带到地表。但是在深层岩石的缓慢抬升过程中，钻石会石墨化（变成石墨），到了地表就不再是宝石了。”

形成钻石所需的条件取决于深度，温度和压力：碳被埋在地球表面以下至少93英里（150公里）处，在每平方英寸约725 000磅的压力（50亿帕斯卡）下加热到约2200华氏度（1 204摄氏度），然后通过火山喷发快速地带到地表层冷却下来。 费托乔克（Fedortchouk）说这一非同寻常的过程使天然可开采的钻石比金矿要更稀少。

但是，福尔（Faul）告诉《生命科学》，在元素成分上，黄金远比钻石要稀少。毕竟，碳是地球上最丰富的元素之一，尤其是与金等重金属相比，而钻石只不过是碳在极高的压力下形成的一种形态。

合成钻石的发明使这个问题（钻石和黄金哪个更稀缺）更复杂了。科学家可以在实验室中重现将石墨转变成钻石的必要条件（无需火山爆发），但对于黄金却做不到（遗憾的是，炼金术仍然是一门伪科学）。根据钻石设计师（Ritani）的说法，即使合成钻石与天然钻石是由相同的物质组成的，但合成钻石在市场上的售价通常会低30％，因为它们不被认为具有和天然钻石同样的价值。

但是，仅仅存在实验室创造的钻石这个事实，是否会使钻石的存在比我们想象的更普遍呢？福尔（Faul）认为确实是这样的：“首先，一定尺寸以下的钻石不值得开采，谁会想购买需要放大镜才能看到的钻石呢？地表上的黄金比大钻石要多，但是钻石作为一类材料并不是特别稀有。我认为，钻石的名声有部分与商家非常成功的公关宣传有关！ ”

本文章最初发表在《生命科学》上。

在开始阅读英文原文之前，请先复习下列核心词汇：

rare - adj. 稀少的

gold - n. 黄金

diamond - n. 钻石

forever - adv. 永远，长久地

precious - adj. 宝贵的，贵重的

jewelry - n. 珠宝饰物

clear-cut - adj. 明确的，清晰的

turn out - 结果是

heavy metal - 重金属

neutron - n. 中子

element - n. 元素

formation - n. 形成，组成

gravitate - v. 被吸引到

crust - n. 山顶

concentration - n. 集中，聚集

present - v. 把...交给，提出

deposit - n. 存款，沉淀物，矿床

feasible - adj. 可行的

pressurize - v. 加压力

carbon - n. 碳

graphite - n. 石墨

lab - n. 实验室

transform - v. 使改变形态

alchemy - n. 炼金术

volcanic - adj. 火山的

eruption - n. 爆发

magnify - v. 放大

在复习了以上词汇后，请将下面的英文原文一口气读完，不要在中途停下来去查那些不认识的单词。有了上面的核心单词打底，你完全可以将整篇文章读完并且理解里面的大致意思。记住，你只要做到大致明白就可以了。

阅读能力和阅读量成正比，要提高阅读量，必须是大量的泛读，如果要对每个不懂的单词都去查字典，那么就不可能通过大量的泛读来提高你的阅读量。

这篇英语原文是《涂博士雅思辅导课》直播班上用来训练学员快速阅读的文章之一。能够快速阅读各个领域的原版文章并找出文中的核心内容，是真正学好英语的最最基础的技能之一，另一个最最基础的技能就是听得懂原版的广播。有了这两个最最基础的技能打底，学员就可以利用好网上大量的原版英语文章和听力资源，不出国就可以把自己沉浸在英语的环境当中。在建立起强大的语感之后，口语和写作能力都会自然成长起来。

如果你对某篇泛读文章特别喜欢，可以在泛读一遍以后再慢慢地精读。如果在精读的过程中对某些句子不是太明白需要讲解，或者你希望以后多看到哪方面的双语阅读，请直接联系涂博士。

Which Is Rarer: Gold or Diamonds?

By Joanna Fantozzi

Live Science Contributor

Diamonds are forever and gold is precious but which is rarer? And does that rarity have anything to do with the price we see at a jewelry store?

The answer it turns out isn't as "clear-cut" as you might think.

Gold — a heavy metal — is one of Earth's rarer elements formed in the collisions of neutron stars said Ulrich Faul an Earth scientist and professor at the Massachusetts Institute of Technology.

Then during the formation of Earth the heaviest elements gravitated toward Earth's core said Yana Fedortchouk an Earth sciences professor and co-director of the Experimental High-Pressure Geological Research Laboratory at Dalhousie University in Halifax in the Canadian province of Nova Scotia. That means that up near the Earth's crust large amounts of gold are hard to find.

You can find it though in low concentrations. It's "present in a large variety of rocks in the crust " Fedortchouk told Live Science. "But in order to form a deposit it needs to reach certain concentrations to make mining economically feasible."

According to Fedortchouk the average concentration of gold in Earth's crust is "very very low " at 4 parts per billion. In order to produce any minable concentration of gold that could be of market value the gold deposit would have to be 1 250 times more concentrated she said.

Diamonds on the other hand are a highly pressurized form of a very common element: carbon. In its non-pressurized form it's known as graphite — the stuff in pencils. Compared with gold the average concentration of carbon in Earth's crust is approximately 200 000 parts per billion according to "Fluids in the Earth's Crust: Their Significance in Metamorphic Tectonic and Chemical Transport Processes" (Elsevier Science Ltd. 1978) a book written by the noted geologist William Fyfe who died in 2013.

So the rarity of diamonds has little to do with their elemental composition; rather the natural transformation of carbon into diamonds that can be mined is an extremely arduous (and rarely successful) process.

"Diamonds can only be produced in the Earth's mantle and somehow be brought to the surface or they can be formed during meteorite impact " but those diamonds are small and never gems Fedortchouk said. (The mantle is the layer of Earth beneath the crust.)"Diamonds formed deep in the Earth's mantle can be brought up by deep magma or pushed up during the slow uplift of deep rocks during mountain growth processes. But during slow uplift diamonds get graphitized [turned into graphite] and never make it up to the surface as gem stones."

The formula required for diamonds to form depends on depth temperature and pressure: Carbon is buried at least 93 miles (150 kilometers) beneath the Earth's surface heated to about 2 200 degrees Fahrenheit (1 204 degrees Celsius) under approximately 725 000 pounds of pressure per square inch (5 billion pascals) and then rapidly brought to the surface by a volcanic eruption to cool. This extraordinary process makes natural minable diamonds rarer than gold Fedortchouk said.

But in its elemental form gold is significantly rarer than diamonds Faul told Live Science. After all carbon is one of the most abundant elements on Earth — especially in comparison to heavier metals like gold — and diamond is simply composed of carbon under immense pressure.

The invention of synthetic diamonds complicates the question even further. Scientists can re-create the conditions necessary to transform graphite into diamonds in a lab — no volcanic eruption necessary — but the same can't be said for gold (sadly alchemy is still a pseudoscience). Even though synthetic diamonds are made of the same substance as natural diamonds according to diamond designer Ritani synthetic diamonds usually sell for 30 percent less on the market because they aren't considered as valuable.

But does the mere existence of lab-created diamonds make these gems more common than we thought? Faul argues that it does: "Diamonds below a certain size are not worth mining in the first place " he said. "Who wants to buy a diamond that needs a magnifying glass to be seen? Gold is more abundant than large diamonds but diamonds as a class of material are not particularly rare. I think part of their reputation has to do with amazing public relations!"

Originally published on Live Science.