In its pure form, gold is an element. Metals form the heaviest elements, of which gold is the heaviest known. Gold is created by nuclear fusion in stars like most other heavy metals. These reactions release energy resulting in titanic explosions called supernovas. What remains from these explosions are dead cores known as neutron stars. Gold is born when two neutron stars collide. The debris left over from such collisions becomes meteorites packed with gold and other metals some of which have collided with Earth. Evidence gathered from South Africa suggests that a great deal of the gold which exists on Earth came here from a meteor about 2 billion years ago.
The qualities of Gold.
Gold is chemically inert and resistant to chemical reaction. It does not tarnish or rust and is soft enough to be easily worked. It can be drawn into wire, alloyed with other metals, and melted and cast into detailed designs such as those of engagement rings Gold can be easily recycled. These properties have all been exploited since ancient times simply by heating gold nuggets at high temperatures and working it with simple tools and moulds. Pure gold is bright yellow, but other colours can be created by alloying it with other metals.
Gold leaf.
Making gold leaf is one of the oldest continuously used creative processes in human history. Gold leaf varies between about four and five-millionths of an inch in thickness. One individual strand of human hair is therefore much thicker than gold leaf. A single 10mm diameter gold nugget can be beaten into a sheet of gold leaf of about one-metre square. The application of gold leaf is called gilding.
Gold has many uses.
50-80% of new gold is used each year in jewellery, and India is the world’s largest consumer. South Asian jewellery is generally of higher purity than gold produced elsewhere in the world, usually at least 22 karats. About 12% of new gold is used each year in electronics, and medicine and dentistry. The other 10% of new gold goes into investments such as coins and bullion. Historically, the Etruscans made dentures using gold wire and animal teeth. Gold has also been marketed for a number of health issues. Because of its exceptional ability to conduct electricity, and its resistance to corrosion, a little gold is used in almost all sophisticated electronic devices. Throughout human history, alchemists have tried to produce gold by transforming it from base metals. This was first attempted in China, and also in ancient Greece. These attempts laid the foundations of modern chemistry.
And finally, Gold is used in space.
Equipment used in space programs contains gold. Gold particles are used for lubrication on satellites and some other aerospace equipment. In certain types of NASA telescopes, the mirrors are finely coated with gold. The visors of astronauts’ helmets are covered with a very thin coating of gold that is partially transparent. Gold leaf is used for these purposes because it has the ability to reflect infrared light but allow the passage of visible light thus protecting astronauts’ eyes.
