Diamonds as the adage goes are forever, seeped in mystery and deceit. The study of world’s biggest and most famous diamond provides a fresh new insight into the Earth’s mantle and the turbulent geological history of our planet.
Researchers have discovered that the largest and the most famous diamonds were created in the Earth’s mantle in an entirely different process as compared to the smaller and more common diamond which make up for the vast majority.
It is a common notion that diamonds are formed within the coal. However, it is now known that diamonds are formed much deeper in the Earth’s Mantle. The planet is made up of three layers. The outer shell which is about 40 kilometres thick is known as the crust. The mantle is the next layer and corresponds to 84% of the planet’s volume. It is here the diamonds are formed and deposited on or near the surface by deep volcanic eruptions.
The innermost layer is the core, which is composed of iron and nickel, is in a dynamic state with areas of solid but occasionally vicious and semifluid rock also. It happens in the region close to the core because there the temperature is close to melting point.
The mantle is made up of 44.8 percent oxygen, 21.5 percent silicon and 22.8% Magnesium with a fair amount of Iron, aluminium, calcium, sodium and potassium. The elements mentioned above or their oxides are bound together in silicate rocks. The most common oxides are silicon dioxide and magnesium dioxide.
The larger diamonds like Cullinan and Lesotho Promise gives us more knowledge about the conditions into the mantle. These diamonds are formed super deep below the depths of 386 kilometres. The research teams from the US got their hands on these diamonds and examined them to confirm the theory that there are pockets of iron –nickel metal within the mantle. The researchers found nano-sized metallic grains composed of a mixture of metallic iron and nickel – as well as carbon, sulphur, methane and hydrogen. The presence of reduced iron and nickel proves that different parts of the mantle have different enrichment levels of oxygen.