It may surprise you to know that in many ways a diamond is no more than a pretty piece of coal. In terms of geology, diamonds and coal are almost exactly the same apart from two key differences. The first being the differing ways the carbon atoms are arranged and the second being the way in which each is formed.

Diamonds are formed deep in the earth. The diamonds that you buy from jewellers are basically heavily compacted pieces of carbon. They have been subjected to extreme pressure underground. They are subjected to a pressure which is thousands of times higher than air pressure and to temperatures of around 2300 Fahrenheit. This sort of pressure and heat which turns carbon to diamond is only found in a very specific area of the earth where the crust and upper mantle meet. This is between 90 and 240 miles below the surface of the earth.

The only other way very small natural diamonds can be formed is if a meteor hits the surface of the earth and produces the conditions needed to create a diamond.