A GUIDE TO DIAMONDS
Diamonds are the oldest gemstones, the youngest diamond having formed no less than 500,000 years ago. It was over this period these amazing natural stones were formed by the great heat and pressure of the earth’s primeval volcanic action.
The chemical composition of the extraordinary crystals formed in the molten rock when pure, crystalline carbon crystals grew producing the hardest natural substance known to man; diamond.
Where Do Diamonds Come From?
Diamonds are not found all bright and shiny as we see them in the finished item of jewellery. In their natural uncut, ‘rough’state, they could be mistaken for pebbles.
The molten volcanic rock in which diamond crystals were formed millions of years ago is called Kimberlite. This is bluish green in colour and is sometimes called “Blue Ground”. It can be found all over the world but only a small number of Kimberlite sites, or pipes as they are called, contain the precious crystals of diamond.
Why Are Diamonds So Valuable?
There are several reasons why diamonds command such high prices. Firstly, very few Kimberlite pipes contain diamonds, when they do, gem quality diamonds are only a tiny percentage of their yield. Secondly, diamond mines tend to be in very inhospitable places – beyond the Artic circle, at the bottom of lakes or at sea and deep in arid deserts – this makes the cost of extraction very high. It is then difficult to extract the diamonds from the earth once a site has been discovered. The first task is to dig down from the top, recover the rock, crush it and extract the diamonds. When the hole becomes too deep, a shaft is sunk alongside the pipe and mining continues from the side.