填空题
.'Diamonds', sang Marilyn Monroe in the film
Gentlemen Prefer Blondes, 'are a girl's best friend.' You might not agree, but you can be sure that diamonds are not only
1 in the world, they are also the most expensive. A single diamond sold for $16.5 million at an
2 in Geneva in 1995!
Diamonds are found in a number of countries including Australia, South Africa, Brazil and the Russian Federation. In fact, there are two main types of diamonds. These are colourless diamonds (about 25% of those found), which have only a few
3 and are usually made into jewellery, and black diamonds—the remaining 75%—which contain a lot of impurities, and are used in industrial
4 . Industrial diamonds are also produced artificially.
The largest diamond ever found is the Cullinan diamond. It weighed 620 grams and was found in a South African diamond mine in 1905. It was bought by the Transvaal Government for ￡150,000, and then presented to the King of England, Edward Ⅶ. The diamond was then
5 nine smaller jewels, which are now part of the British crown jewels. These jewels belong to the British government and are kept in the Tower of London.