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How Old is Gold?
The planet is 4.5 billion years old, and there are substantial gold deposits on every continent throughout the world.
How is gold formed? What are the types of rocks gold is found in? How old is gold?
Gold is the most precious metal in the world.
All metals, as indeed are minerals, have been formed in the Earth itself.
There is even some suggestion that gold sometimes arrives from outer space, as asteroids hit our planet.
But evidence from gold-rich South Africa shows us that that the gold they mine is almost as old as the Earth itself.
It has often been said that gold can be found almost anywhere.
Such is its value that even flecks of it is valuable to the gold prospector. Where one fleck is present, there are almost certainly other flecks.
Where a seam of gold exists underground, there is always some company or another willing to put up the resources to mine it.
Underground mining is dangerous work. Wages to work in such mines are high (or should be). The reason why we don't all own a gold mine is because we don't have enough money for the start-up costs.
For the geologist, however, the interest lies in finding out how old the gold is.
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South African gold is 2+ billion years old
Gold is found in alluvial deposits, placer deposits and hydrothermal veins within volcanic rocks.
Some of the biggest gold mines in the world are in South Africa.
The largest is in the Witwatersrand Basin situated between the Transvaal and the Orange Free State.
The Witwatersrand Basin is within the area of the Vredefort crater which is the site of the largest asteroid crater in the world.
There is evidence to suggest that a 5 - 10 km (3 - 6 miles) wide asteroid hit the Earth there just over 2,000 million years ago.
Lucky for some this asteroid was either made of, or contained large amounts of gold, and spread it over a wide and deep area.
The Rand, as the gold mine is known, has produced tremendous amounts of gold, even from as far underground as 4,000 metres.
Of course the gold is much older than the 2 billion years or so that it has been on Earth.
There is some evidence to suggest that gold can form when neutron stars collide in supernova explosions.
Jason Kirk, a geochemist at the University of Arizona in Tucson led a team of scientists trying to date the Rand gold by measuring the radiometric dating of elements sometimes found within gold.
Gold itself cannot be dated by this method as it contains no carbon.
Their results were published in the Science Magazine, and showed the gold to be 3 billion years old.
Where can gold be found?
Gold is at the Earth's core.
Although it is a soft metal, only 2.5 on the Moh's scale, gold is a heavy metal and it is believed most of it formed at the same time as Earth and later sank to the core, which mainly consists of iron.
There is some evidence to suggest that gold is sometimes extruded from beneath the Earth's mantle through volcanic plumes.
Small specks or nuggets of gold is to be found in igneous rocks the world over. Hydrothermal veins containing quartz are a good places to look.
There are also huge concentrations of it in seawater, but the cost of extraction is higher than the value of the gold recoverable.
It is the 75th most abundant element on the planet, but is so widespread and in such minute amounts, most gold prospectors would be hard pushed to find and collect them.
Large nuggets can be found the world over in soft alluvial deposits on or near the ground surface. They almost certainly all arrive from outer space with asteroids or meteorites.
- Facts about Gold
Learn all about gold, its composition, where it can be found, it's value, origin and uses.
So how old is gold?
All gold is more than likely 2 to 3 billion years old, or perhaps even older.
It is quite amazing to think that the gold ring you are wearing could have been formed billions of years ago in a supernova explosion.
Gold cannot be man-made. Many have tried and failed, such are its unique properties. It stands out among other metal as it is extremely stable and cannot rust or tarnish.
So is most gold found in South Africa and Australia?
The absolutely fascinating thing about gold finds, is that every shooting star you see could be bringing in more gold.
Scientists believe than man has found all the gold deposits on Earth, except what has been sucked into the iron-rich inner core.
New gold deposits, or nuggets, could be arriving daily via meteorites.
Having said that, if I lived in an area where gold has been found, I'd be out there with a gold metal detector, the best I could afford.
But did you know that Australia and South Africa were not always in the same position?
Have you heard of Pangaea?
Pangaea is the name scientists have given to the continent formed when Europe was part of America.
But, before that, all the continents and countries were adrift.
So if you think ancient gold can only be found on continents that are currently showing gold deposits, think again.
We were all little islands floating in shallow seas once. Most land masses were separate. Some of our countries floated well north of the equator, and others south.
Even when we joined together, our positions changed from north to south, east to west.
Gold can be found all over the world.
There are huge deposits in sea water, but it costs more to filter it out than it costs to buy directly from a shop.
Gold is very old, older than most us can imagine.
It can also be found all over the world. We just have to find it.