听力文本

Gold!
It used to be said there was a pot of gold at the end of the rainbow, though no one has ever found it. Yet men have left their business and their families and homes and gone to the ends of the earth in search of goldand to find a short cut to riches, for gold is used for money all over the World, though small coins are notmade of it because they would have to be too small and would easily be lost.
The largest gold mines in the World are in South Africa, and more than half of the gold in the World comes from gold mines near a city there called Johannesburg.
Gold is called the king of metals, for though platinum is more valuable, gold can be used for money and for ornament and for other things, and most people think it more beautiful. Pure gold is stamped 24 karat, but pure gold is so soft it wears away too easily and some other metal is usually mixed with it to make it harder. The finest rings and jewelry are usually 18 karat, which means that eighteen parts are of pure gold and six parts are of another metal. Look on a ring or watch and see if you can find the figures 18 K or 14 K stamped there.
Sometimes gold is found in little lumps which are called nuggets, but usually it is mixed through the rock and doesn’t show at all. The rock has to be ground to powder and then the gold separated from the powder.
Almost every family has at least one thing that has come from South Africa—a very small thing but a very valuable one. Can you guess what it is? The diamond in your mother’s ring. Nearly all the diamonds in the World come from a place called Kimberley in South Africa. They are found in a kind of blue clay in what used tobe volcanoes.
Most of the diamonds used to be sent to Amsterdam in Holland to be cut and polished. The reason they are sent there rather than to some other country is because the diamond mines were first discovered by Dutch peopleliving in South Africa.

参考译文

金子！
过去人们常说在彩虹的尽头有一罐金子。不过从未有人找到过。然而，人们还是放下手头的工作，离开亲人和家乡，到天涯海角去寻找金子，期望找到致富的捷径，因为金子在世界各地都可作货币使用。不过小钱币并不是用金子做的，因为它们太小又容易丢失。
世界上最大的金矿在南非。世界上一半以上的金子产于南非金矿，这些金矿位于一座名叫约翰内斯堡的城市附近。
金子被称为“金属之王”，因为虽然白金更贵重，但金子可以用作货币，用来装饰，还有很多其他用途，而且大多数人认为金子更漂亮。纯金上都压印着24K的标记，但是纯金质软，很容易磨损，通常用金和其他金属制成合金，以增大硬度。最好的戒指和珠宝通常是18K的，这表示其中四分之三是纯金，四分之一是另一种金属。查看一枚戒指或一只手表，看看你能否找18K或14K的印记。
有时候，金子被发现时是一小块一小块，叫做天然金块。但通常金子都混在岩石中，一点都看不出。只有把岩石碾磨成粉，才能把金子从粉末中分离出来。
在美国，几乎每个家庭都至少有一件东西来自南非——一件很小但很贵重的东西。你能猜到是什么吗？它就是你母亲戒指上的钻石。几乎世界上所有的钻石都来自南非一个叫金伯利的地方。钻石是在一种蓝色黏土中被发现的，发现的地点以前是火山。
过去大多数钻石都运送至荷兰的阿姆斯特丹进行切割和打磨。之所以送到荷兰而不是其他国家，是因为钻石矿最初是由居住在南非的荷兰人发现的。