Gold is the name of a yellow metal which has been derived from the Old English word 'geolu' meaning yellow and has been the source of fascination for human beings since the inception of civilization. The ancient civilizations were mesmerized by the shining properties of this metal and used it extensively to make ornaments and jewelry. The progress of mankind resulted in the use of gold as currency and gold coins of various denominations have been the hallmark of many legendary rulers who reigned in different parts of the world. The unflinching faith in this metal continued into the modern epoch as well when gold was used as a standard for global currencies and still remains a part of our lives through its usage in the medical field as well as in electronic devices.
The chemical symbol for gold is Au and it is derived from the Latin word for gold, aurum. Since it is an element of the Earth, its atomic number is 79 and it is classified as a transitional metal in the Periodic Table. As a metal gold is attributed with unique physical and chemical properties due to which it is the only metal which does not form an oxide film on its surface when it comes in contact with air at room temperature and this implies that it is not prone to rust or tarnish. The natural and pure color of gold is yellow but when it is mixed with other metals, it acquires a different tinge which depends upon the metal with which it is combined. Therefore, if gold is mixed with varying amounts of copper and silver it turns red, yellow or green where as if it is alloyed with nickel, zinc and copper it acquires a white color and is known as white gold. The natural alloy of gold and silver is known as electrum and the unique combination of gold and mercury is known as gold amalgam.
The reason why gold has been accorded a high status in our society is because of its many unique properties which distinguish it from other metals and these properties are listed as follows:
- Gold has been accorded the status of being a noble metal due to the fact that it does not oxidize in normal conditions and is therefore free from the problem of rusting and tarnishing.
- This metal is indestructible which implies that it is immune to physical destruction of any kind and can be recycled and used as many times by the owner.
- It is soluble in aqueous mixtures containing halogens and iodides as well as oxidizing mixtures like aqua regia.
- Gold is one of the best conductors of electricity due to which it is used in circuits of motor vehicles, satellites and aircraft.
- Gold is ductile and malleable due to which it can be easily drawn into thin and long wires and can also be pounded into sheets which are so thin that they allow the passage of light.
- Since this metal completely reflects infrared rays, it is used widely for radiation reflection and is a good conductor of thermal energy.
Some of the ways in which gold has been glorified in our society are:
- Gold was used to adorn the remarkable feat by the tennis player Roger Federer when he won the Grand Slam tennis tournament at Wimbledon for the fifteenth time in July, 2009.
- The 1933 Double Eagle is one of the rarest gold coins in the world which also became one of the most expensive when it was sold for $7.59 million at Sotheby's auction house in New York in 2002.
- The famous singer Elvis had a Stutz in which all the fittings which are made in chrome for normal cars are in gold.
The purity of gold is measured by the term 'carat' and the purest form of gold is designated as being 24 carats. The word carat is a modification of the word 'carob' meaning carob seeds which were used for balancing scales in Oriental markets.
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