Properties of Gold
The high price of gold is a reflection of the fact that this highly prized metal is relatively rare. In fact, the amount of gold that exists in the Earth's crust is only four millionths of the total mass. In order to recover just a tiny cube of gold measuring a cubic centimetre, you would need to excavate more than 250 truckloads of earth, each containing 20 tonnes.
The chemical symbol for gold is Au, taken from the Latin word, Aurum, meaning gold. Many people think that lead is the heaviest metal there is, but in fact, gold is much heavier. It weighs 19.3 g per cubic centimetre.
The physical attractiveness of gold is part of what makes it so suitable for making into jewellery and other ornamental objects. Its rich yellow colour and lustre have been valued since it was first processed around 6,000 years ago. But that's not the only reason gold is such a useful material.
Gold is Inert
This means it doesn't react to most other substances or chemicals and it's the reason why gold is resistant to tarnishing and corroding. This quality makes it highly desirable as a metal for use in jewellery and explains why archaeologists are able to dig up gold artefacts that are in good condition despite having been buried for many thousands of years. Gold can be dissolved in mercury to make an amalgam, which may be used in gold teeth, but it doesn't actually react with the mercury.
Gold is Malleable
This means it can be easily hammered and beaten to form thin sheets or worked into intricate shapes. This makes it a wonderful metal for jewellers to work with and shape into exquisite objects. In fact, gold is the most malleable element that exists, so much so that just one ounce of it can be hammered into a sheet just a few millionths of an inch thick but which would measure 300 square feet. Gold is widely used to gild items such as picture frames and furniture and in the hands of a highly skilled craftsman or woman can be applied to uneven surfaces giving a wonderful finish.
Gold is Ductile
It can be stretched out into a very thin wire without breaking. Just one ounce can be drawn into a wire 50 miles long. It would measure 5 microns in diameter and is ideal for making electrical contacts.
Gold is a Good Conductor
Its ability to conduct electricity means that gold is widely used throughout the electronics manufacturing industry. Most electronic items that are made will contain a small amount. It's used for electrical contacts and circuit boards and you'll find it in mobile phones, calculators and computers.
Gold is Reflective
It can reflect not just heat but also infrared radiation and this has meant gold has been widely used by NASA in the space program. Gold-coated plastic film is used on the outside of spacecraft to protect it from solar radiation and help stabilise the craft's temperature. Much closer to home, recordable CDs depend on gold to reflect a laser beam. Silver and copper are also highly reflective but aren't suitable to use in this application because they tarnish and oxidise easily.
Gold is Edible
Perhaps not its best-known property, but certainly gold can be eaten in very small amounts. Gold leaf can be used to decorate food and it's contained in certain alcoholic drinks such as Goldschläger. However, as with any other precious metal, too much would not be a good thing and eating gold to excess would lead to heavy metal poisoning. Much better and safer to wear it in the form of jewellery!
Where does gold come from?
The biggest proportion of gold we have is mined. It's contained in gravel and quartz veins. South Africa is the biggest producer, being responsible for two thirds of the world's supply, but gold is also mined in the USA, Canada, Russia, Australia and China. Various processes are used to recover the gold from its ores, such as cyaniding, amalgamating and smelting and electrolysis is also used in the refining process. Some gold exists in sea water, but no efficient method of extracting it from this source has yet been discovered.
How Much Gold is There?
The annual production of gold is about 2,500 tonnes worldwide and, of course, much more of this precious metal exists in reserves. It has been estimated that if all the gold that has ever been found were to be put together, it would create a cube with sides measuring 60 feet and its value would stand at something like $3.7 trillion.
The properties of gold that have been outlined here show that this rare and precious metal is so much more than just a pretty face, although it is undoubtedly that too. Gold has exerted an attraction to men and women since it was first used all those thousands of years ago and its ability to captivate continues today, along with its very real and practical uses in the fields of medicine, dentistry, science and electronics.
