It is hard to believe that a link exists between the dark brown-black lumps of coal and shining diamonds. What they have in common is that both are composed of carbon. It exists on earth in 3 different forms. The first is amorphous and has no crystal structure, the second is called graphite and is composed of hexagonal crystals. Diamonds are the third form of carbon. These shining precious stones have cubic crystals.
The connection between coal and diamonds
Coal, the amorphous form of carbon, is not made of pure carbon. It is composed of complex organic molecules of decomposed plants and animals, which have been compressed for millions of years in the Earth's crust. Coal stones can be subjected to various geological processes, which change the compounds and transform them into their almost purest form, called graphite.
This process requires suitable conditions and millions of years. Diamonds form deep in the earth, where the temperature and pressure are incredibly high. They are transported to the surface by magma.
If both diamonds and graphite are made of carbon, then why do they look so different? The answer lies in the arrangement of the carbon atoms. In graphite, they are arranged in a hexagonal shape, while in diamonds, every atom is connected with 6 other atoms in a tetrahedral pattern. That is why graphite has atoms bundled atop each other on the surface, while in diamonds they are arranged in a pyramid shape. The flat surface of graphite absorbs light of different wavelengths, which is why it is murky and black. The pyramidal structure of a diamond does not have this capability and that is the reason for its transparency and shine.
How coal stones turn to diamonds
The transformation of coal to diamonds is almost impossible. Even if there are carbon atoms in coal, the amount of impurities is so great that it takes millions of years for them to transform into the most purest form - graphite. And the transformation from graphite to diamond takes a few more million years. This metamorphosis cannot take place on the Earth's surface, since they form deep in the earth.
The process occurs about 100 miles under the surface, where the coal stones are subjected to numerous geological processes. It is believed that they are exposed to temperatures of over 200 degrees Fahrenheit and a pressure 50 times greater than that found on the surface. Every single variation of these factors can have an effect on the creation of diamonds. A change in pressure or increase in temperature can lead to them melting.
Even if the diamonds were to form in this way, it takes another 2000 to 3000 years for them to come out on the surface. Molten magma transports and cools them, in order to turn into stones in the form of kimberlite pipes. It is kimberlite pipes, which are seen as suitable places for opening diamond mines. It is possible for the diamonds to be carried away farther off as a result of kimberlite erosion. However, raw precious stones are found in the kimberlite zones and areas near them.
The question of how coal turns to diamonds has caused much doubts. It is difficult for people to believe that something as disgusting as coal can turn into something as beautiful and precious as a diamond. Even though it is possible, it must be noted that it is not an easy process. It takes mother nature millions of years to create 1 diamond, and 1 karat requires about 100 tons of mud. So - how will you transform coal into diamonds? It is impossible and you cannot do it yourself - it is a natural process that takes millions of years.